Hyperfluorescent organic light-emitting diodes(HF-OLEDs)approach has made it possible to achieve excellent device performance and color purity with low roll-off using noble-metal-free pure organic emitter.Despite sign...Hyperfluorescent organic light-emitting diodes(HF-OLEDs)approach has made it possible to achieve excellent device performance and color purity with low roll-off using noble-metal-free pure organic emitter.Despite significant progress,the performance of HF-OLEDs is still unsatisfactory due to the existence of a competitive dexter energy transfer(DET)pathway.In this contribution,two boron dipyrromethene(BODIPY)-based donor-acceptor emitters(BDP-C-Cz and BDP-N-Cz)with hybridized local and charge transfer characteristics(HLCT)are introduced in the HF-OLED to suppress the exciton loss by dexter mechanism,and a breakthrough performance with low-efficiency roll-off(0.3%)even at high brightness(1000 cd m^(-2))is achieved.It is demonstrated that the energy loss via the DET channel can be suppressed in HF-OLEDs utilizing the HLCT emitter,as the excitons from the dark triplet state of such emitters are funneled to its emissive singlet state following the hot-exciton mechanism.The developed HF-OLED device has realized a good maximum external quantum efficiency(EQE)of 19.25%at brightness of 1000 cd m^(-2)and maximum luminance over 60000 cd m^(-2),with an emission peak at 602 nm and Commission International de L'Eclairage(CIE)coordinates(0.57,0.41),which is among the best-achieved results in solution-processed HF-OLEDs.This work presents a viable methodology to suppress energy loss and achieve high performance in the HF-OLEDs.展开更多
The successful utilization of an eco-friendly and biocompatible parylene-C substrate for high-performance solution-processed double-walled carbon nanotube(CNT)electrode-based perovskite solar cells(PSCs)was demonstrat...The successful utilization of an eco-friendly and biocompatible parylene-C substrate for high-performance solution-processed double-walled carbon nanotube(CNT)electrode-based perovskite solar cells(PSCs)was demonstrated.Through the use of a novel inversion transfer technique,vertical separation of the binders from the CNTs was induced,rendering a stronger p-doping effect and thereby a higher conductivity of the CNTs.The resulting foldable devices exhibited a power conversion efficiency of 18.11%,which is the highest reported among CNT transparent electrode-based PSCs to date,and withstood more than 10,000 folding cycles at a radius of 0.5 mm,demonstrating unprecedented mechanical stability.Furthermore,solar modules were fabricated using entirely laser scribing processes to assess the potential of the solution-processable nanocarbon electrode.Notably,this is the only one to be processed entirely by the laser scribing process and to be biocompatible as well as eco-friendly among the previously reported nonindium tin oxide-based perovskite solar modules.展开更多
Artificial sensory systems have emerged as pivotal technologies to bridge the gap between the virtual and real-world,replicating human senses to interact intelligently with external stimuli.To practically apply artifi...Artificial sensory systems have emerged as pivotal technologies to bridge the gap between the virtual and real-world,replicating human senses to interact intelligently with external stimuli.To practically apply artificial sensory systems in the real-world,it is essential to mass-produce nanomaterials with ensured sensitivity and selectivity,purify them for desired functions,and integrate them into large-area sensory devices through assembly techniques.A comprehensive understanding of each process parameter from material processing to device assembly is crucial for achieving a high-performing artificial sensory system.This review provides a technological framework for fabricating high-performance artificial sensory systems,covering material processing to device integrations.We introduce recent approaches for dispersing and purifying various nanomaterials including 0D,1D,and 2D nanomaterials.We then highlight advanced coating and printing techniques of the solution-processed nanomaterials based on representative three methods including(i)evaporation-based assembly,(ii)assisted assembly,and(iii)direct patterning.We explore the application and performances of these solution-processed materials and printing methods in fabricating sensory devices mimicking five human senses including vision,olfaction,gustation,hearing,and tactile perception.Finally,we suggest an outlook for possible future research directions to solve the remaining challenges of the artificial sensory systems such as ambient stability,device consistency,and integration with AI-based software.展开更多
Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materia...Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.展开更多
Solution processability and flexibility still remain major challenges for many thermoelectric(TE)materials,including bismuth telluride(Bi_(2)Te_(3)),a typical and commercially available TE material.Here,we report a ne...Solution processability and flexibility still remain major challenges for many thermoelectric(TE)materials,including bismuth telluride(Bi_(2)Te_(3)),a typical and commercially available TE material.Here,we report a new solutionprocessed method to prepare a flexible film of a Bi_(2)Te_(3)/single-walled carbon nanotube(SWCNT)hybrid,where the dissolved Bi_(2)Te_(3) ion precursors are mixed with dispersed SWCNTs in solution and recrystallized on the SWCNT surfaces to form a“cement-rebar”-like architecture.The hybrid film shows an n-type characteristic,with a stable Seebeck coefficient of^(−1)00.00±1.69μVK^(−1) in air.Furthermore,an extremely low in-plane thermal conductivity of∼0.33Wm^(−1) K^(−1) is achieved at 300 K,and the figure of merit(ZT)reaches 0.47±0.02.In addition,the TE performance is independent of mechanical bending.The unique“cement-rebar”-like architecture is believed to be responsible for the excellent TE performances and the high flexibility.The results provide a new avenue for the fabrication of solution-processable and flexible TE hybrid films and will speed up the applications of flexible electronics and energy conversion.展开更多
Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state ligh...Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state lighting in the future.The TQLED is a multilayer structure device which connects two or more light-emitting units by using an interconnection layer(ICL),which plays an extremely important role in the TQLED.Therefore,realizing an effective ICL is the key to obtain high-efficiency TQLEDs.In this work,the p-type materials polys(3,4-ethylenedioxythiophene),poly(styrenesulfonate)(PEDOT:PSS)and the n-type material zinc magnesium oxide(ZnMgO),were used,and an effective hybrid ICL,the PEDOT:PSS-GO/ZnMgO,was obtained by doping graphene oxide(GO)into PEDOT:PSS.The effect of GO additive on the ICL was systematically investigated.It exhibits that the GO additive brought the fine charge carrier generation and injection capacity simultaneously.Thus,the all solutionprocessed red TQLEDs were prepared and characterized for the first time.The maximum luminance of 40877 cd/m^(2) and the highest current efficiency of 19.6 cd/A were achieved,respectively,showing a 21%growth and a 51%increase when compared with those of the reference device without GO.The encouraging results suggest that our investigation paves the way for efficient all solution-processed TQLEDs.展开更多
Polymer field-effect transistors operated in the n-channel model with a top-gate/bottom-contact are processed using a solution method. The transistor performance depends on the gate dielectric layer. A high performanc...Polymer field-effect transistors operated in the n-channel model with a top-gate/bottom-contact are processed using a solution method. The transistor performance depends on the gate dielectric layer. A high performance polymer transistor is achieved, with the saturated electron mobility of about 0.46cm2/Vs, threshold voltage nearly 0 V and subthreshold sway of about 0.9 V/decade, employing a polystyrene （PS） dielectric layer. The transistor performances are further improved with increasing current and lower operation voltages by utilizing a bi-layer gate dielectric, comprising a thin PS dielectric layer adjacent to the semiconductor to minimize the density of the interface traps for obtaining a small VT, a large μ and a poly（methyl methacrylate） （PMMA） dielectric layer with a relatively high-k adjacent to the gate electrode for enlarging the capacitance, processed from the orthogonal solvents.展开更多
The solution-processed method for organic light-emitting diodes(OLEDs)offers the benefits of cost-effectiveness and enhanced material utilization.In the multilayer architecture of solution-processed OLEDs(SOLEDs),the ...The solution-processed method for organic light-emitting diodes(OLEDs)offers the benefits of cost-effectiveness and enhanced material utilization.In the multilayer architecture of solution-processed OLEDs(SOLEDs),the role of hole-transport materials(HTMs)is pivotal for cascade hole injection.However,commercial HTMs such as poly-(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine)(TFB)are hampered by incompatible energy levels and redissolution with overlayer solvent,prompting the exploration of cross-linkable HTMs(X-HTMs)for better performance.In this study,we have developed two novel small-molecule X-HTMs,N^(1),N^(1)′-((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(N^(4),N^(4)-diphenyl-N^(1)-(4-vinylphenyl)benzene-1,4-diamine)(FTPA-V)and N,N′-((perfluoropropane-2,2-diyl)bis-(4,1-phenylene))bis(9-phenyl-N-(4-vinylphenyl)-9H-carbazol-3-amine)(FPCz-V),which incorporate thermally cross-linkable vinyl groups and electron-rich trifluoromethyl units.The X-HTMs enhance interfacial contact through superior film formation and solvent resistance,along with optimal energy levels.The application of X-HTMs significantly enhances the efficiencies and longevities of blue,green,and red SOLEDs.Specially,blue SOLED incorporating FPCz-V exhibits unprecedented lifetime(LT95)extending to over 150 h,setting a new record for blue SOLEDs.The electrochemistry stability,high bond dissociation energy,and triplet energy levels of X-HTMs can effectively minimize exciton annihilation and prolong the lifetime.These findings underscore the potential of X-HTM optimization to propel the development of stable solution-processed luminescent technologies.展开更多
The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized ...The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.展开更多
All-solution-processed organic solar cells(OSCs)(from the bottom electrode to the top electrode)are highly attractive thanks to their low cost,lightweight and high-throughput production.However,achieving highly effici...All-solution-processed organic solar cells(OSCs)(from the bottom electrode to the top electrode)are highly attractive thanks to their low cost,lightweight and high-throughput production.However,achieving highly efficient all-solution-processed OSCs remains a significant challenge.One of the key issues is the lack of high-quality solution-processed electrode systems that can replace indium tin oxide(ITO)and vacuum-deposited metal electrodes.In this paper,we comprehensively review recent advances in all-solution-processed osCs,and classified the devices as the top electrode materials,including silver nanowires(AgNWs),conducting polymers and composite conducting materials.The correlation between electrode materials,properties of electrodes,and device performance in all-solution-processed OSCs is elucidated.In addition,the critical roles of the active layer and interface layer are also discussed.Finally,the prospects and challenges of all-solution-processed OSCs are presented.展开更多
Wearable smart sensors are considered to be the new generation of personal portable devices for health monitoring.By attaching to the skin surface,these sensors are closely related to body signals(such as heart rate,b...Wearable smart sensors are considered to be the new generation of personal portable devices for health monitoring.By attaching to the skin surface,these sensors are closely related to body signals(such as heart rate,blood oxygen saturation,breath markers,etc.)and ambient signals(such as ultraviolet radiation,inflammable and explosive,toxic and harmful gases),thus providing new opportunities for human activity monitoring and personal telemedicine care.Here we focus on photodetectors and gas sensors built from metal chalcogenide,which have made great progress in recent years.Firstly,we present an overview of healthcare applications based on photodetectors and gas sensors,and discuss the requirement associated with these applications in detail.We then discuss advantages and properties of solution-processable metal chalcogenides,followed by some recent achievements in health monitoring with photodetectors and gas sensors based on metal chalcogenides.Last we present further research directions and challenges to develop an integrated wearable platform for monitoring human activity and personal healthcare.展开更多
Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are develope...Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs).It is found that the non-conjugated polynorbornenes can keep high triplet energy(ET)levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units,making them capable as host materials for blue emitters.Meanwhile,by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan,the highest occupied molecular orbital(HOMO)levels for the polymer hosts are elevated from-5.50 eV to-5.11 eV,beneficial for reducing the hole injection barrier from anode to emissive layer.As a result,solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain(PNB-TAc)as host and boron,selenium,nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm,full-width at half maximum of 30 nm,together with maximum external quantum efficiency of 20.2%,representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.展开更多
Ionic thermally activated delayed fluorescence(TADF)emitters are rarely investigated due to their poor photoluminescence and electroluminescence performance.Herein,highly efficient ionic TADF emitters with charged do...Ionic thermally activated delayed fluorescence(TADF)emitters are rarely investigated due to their poor photoluminescence and electroluminescence performance.Herein,highly efficient ionic TADF emitters with charged donor–acceptor(D–A^(+))and D–A^(+)–D architectures are designed,innovatively based on the phosphonium cation electron acceptor.The symmetric D–A^(+)–D compound in doped film exhibits a high photoluminescence quantum yield of 0.91 and a short emission lifetime of 1.43 microseconds.Partially solution-processed organic lightemitting diodes based on these ionic TADF emitters achieve a maximum external quantum efficiency(EQE)of 18.3%and a peak luminance of 14,532 candelas per square meter(cd/m^(2))and show a small efficiency roll-off of 7.1%(EQE=17%)at a practical high luminance of 1000 cd/m^(2).These results demonstrate the high potential of phosphonium cations as promising electron acceptors to construct TADF emitters for high-performance electroluminescence devices.The current study opens up an appealing way for future exploitation of high-efficiency ionic TADF materials.展开更多
High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for explo...High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.展开更多
A solution-processed CuOx film has been successfully integrated as the hole-transporting layer（HTL） for inverted planar heterojunction perovskite solar cells（PVSCs）. The CuOx layer is fabricated by simply spin-coa...A solution-processed CuOx film has been successfully integrated as the hole-transporting layer（HTL） for inverted planar heterojunction perovskite solar cells（PVSCs）. The CuOx layer is fabricated by simply spin-coating a copper acetylacetonate（Cu（acac）2） chloroform solution onto ITO glass with high transparency in the visible range. The compact and pinhole-free perovskite film with large grain domains is grown on the CuOx film. The inverted PVSCs with the structure of ITO/CuOx/MAPbI3/PC（61）BM/ZnO/Al are fabricated and show a best PCE of 17.43% under standard AM 1.5G simulated solar irradiation with a VOCof 1.03 V, aJ（SC） of 22.42 mA cm^（-2）, and a fill factor of 0.76, which is significantly higher and more stable than that fabricated from the often used hole-transporting material PEDOT：PSS（11.98%） under the same experimental conditions. The enhanced performance is attributed to the efficient hole extraction through the CuOx layer as well as the high-quality CH3NH3PbI3 films grown on the CuOx. Our results indicate that low-cost and solution-processed CuOx film is a promising HTL for high performance PVSCs with better stability.展开更多
All-inorganic cesium lead bromide(CsPbBr3)perovskite is attracting growing interest as functional materials in photovoltaics and other optoelectronic devices due to its superb stability.However,the fabrication of high...All-inorganic cesium lead bromide(CsPbBr3)perovskite is attracting growing interest as functional materials in photovoltaics and other optoelectronic devices due to its superb stability.However,the fabrication of high-quality CsPbBr3 films still remains a big challenge by solution-process because of the low solubility of the cesium precursor in common solvents.Herein,we report a facile solution-processed approach to prepare high-quality CsPbBr3 perovskite films via a two-step spin-coating method,in which the Cs Br methanol/H2 O mixed solvent solution is spin-coated onto the lead bromide films,followed by an isopropanol-assisted post-treatment to regulate the crystallization process and to control the film morphology.In this fashion,dense and uniform CsPbBr3 films are obtained consisting of large crystalline domains with sizes up to microns and low defect density.The effectiveness of the resulting CsPbBr3 films is further examined in perovskite solar cells(PSCs)with a simplified planar architecture of fluorine–doped tin oxide/compact Ti O2/CsPbBr3/carbon,which deliver a maximum power conversion efficiency of 8.11%together with excellent thermal and humidity stability.The present work offers a simple and effective strategy in fabrication of high-quality CsPbBr3 films for efficient and stable PSCs as well as other optoelectronic devices.展开更多
The much slower progress in enhancing the thermoelectric performance of n-type Bi2Te3 than that of p-type Bi2Te3 based materials in the past decade hinders the widespread use in power generation and refrigeration. Her...The much slower progress in enhancing the thermoelectric performance of n-type Bi2Te3 than that of p-type Bi2Te3 based materials in the past decade hinders the widespread use in power generation and refrigeration. Here, a facile bottom-up solution-synthesis with spark plasma sintering(SPS) process has been developed to build n-type Bi2Te3-xSex bulk nanocomposites, which substantially improves the power factor and decreases the lattice thermal conductivity by tuning the interface scattering of phonons and electrons. The stoichiometric composition in ternary Bi2Te3-xSex nanocomposites is also tuned to optimize the carrier concentration and lattice thermal conductivity. The optimized bulk nanocomposite Bi2Te2.7Se0.3 exhibits a ZT of 1.1 at^371 K, which is comparable to the corresponding commercially available ingots. Our results demonstrate the great potential of the solution-processed n-type Bi2Te3-xSex nanocomposites for cost-effective thermoelectric applications.展开更多
Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through soluti...Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.展开更多
With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emittin...With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emitting diodes(OLEDs)owing to their thermally activated delayed fluorescence(TADF)nature.However,the highly rigid molecular skeleton with the oppositely positioned bo ron and nitrogen in generating MR effects results in the intrinsic difficulties in the solution-processing of MR-OLEDs.Here,we demonstrate a facile strategy to increase the solubility,enhance the efficiencies and modulate emission color of MR-TADF molecules by extending aromatic rings and introducing tert-butyls into the MR backbone.Two MR-TADF emitters with smaller singlet-triplet splitting energies(ΔE~(ST))and larger oscillator strengths were prepared conveniently,and the solution-processed MR-OLEDs were fabricated for the first time,exhibiting efficient bluish-green electroluminescence with narrow FWHM of 32 nm and external quantum efficiency of 16.3%,which are even comparable to the state-of-the-art performances of the vacuum-evaporated devices.These results prove the feasibility of designing efficient solutionprocessible MR molecules,offering important clues in developing high-performance solution-processed MR-OLEDs with high efficiency and color purity.展开更多
Two-dimensional(2 D)covalent organic frameworks(COFs)with periodic functionalπ-electron systems are an emerging class of optoelectronic materials.However,almost all conjugated COFs so far are insoluble and hard to pr...Two-dimensional(2 D)covalent organic frameworks(COFs)with periodic functionalπ-electron systems are an emerging class of optoelectronic materials.However,almost all conjugated COFs so far are insoluble and hard to process,which hampers severely their optoelectronic applications.Here,a solution-processable,nanoscale and sp2 carbon-conjugated COF-like material,PDPP-C20 was successfully designed and synthesized.The solution-processed PDPP-C20 films exhibit high crystallinity and excellent charge transport properties along out-of-plane directions,combined with the highest occupied molecular orbital(HOMO)/lowest unoccupied molecular orbital(LUMO)levels of-5.36/-3.75 e V,making PDPP-C20 suitable for electronic device applications.An efficiency as high as 21.92%has been demonstrated when it was used as a functional interfacial layer in perovskite solar cells,coupled with dramatically improved stability in comparison with the control device due to the superior hydrophobicity of PDPP-C20 layer as well as its passivation effect on perovskite surface.Furthermore,the soluble PDPP-C20 could also be used as donor in bulk-heterojunction organic solar cells and an initial efficiency of 2.46%has been achieved.These results indicate that this new class of soluble and nanoscale COF-like materials should offer a new arena of functional materials for optoelectronic devices.展开更多
基金supported by Guangdong Foundation of Basic and Applied Basic Research(2019B1515120023,2022B1515020041)National Natural Science Foundation of China(21975053,21975055,U2001222)for financial support
文摘Hyperfluorescent organic light-emitting diodes(HF-OLEDs)approach has made it possible to achieve excellent device performance and color purity with low roll-off using noble-metal-free pure organic emitter.Despite significant progress,the performance of HF-OLEDs is still unsatisfactory due to the existence of a competitive dexter energy transfer(DET)pathway.In this contribution,two boron dipyrromethene(BODIPY)-based donor-acceptor emitters(BDP-C-Cz and BDP-N-Cz)with hybridized local and charge transfer characteristics(HLCT)are introduced in the HF-OLED to suppress the exciton loss by dexter mechanism,and a breakthrough performance with low-efficiency roll-off(0.3%)even at high brightness(1000 cd m^(-2))is achieved.It is demonstrated that the energy loss via the DET channel can be suppressed in HF-OLEDs utilizing the HLCT emitter,as the excitons from the dark triplet state of such emitters are funneled to its emissive singlet state following the hot-exciton mechanism.The developed HF-OLED device has realized a good maximum external quantum efficiency(EQE)of 19.25%at brightness of 1000 cd m^(-2)and maximum luminance over 60000 cd m^(-2),with an emission peak at 602 nm and Commission International de L'Eclairage(CIE)coordinates(0.57,0.41),which is among the best-achieved results in solution-processed HF-OLEDs.This work presents a viable methodology to suppress energy loss and achieve high performance in the HF-OLEDs.
基金supported by the National Research Foundation of Korea funded by the Ministry of Science and ICT (MSIT),Korea (NRF-2021R1C1C1009200 and 2023R1A2C3007358)supported by the Defense Challengeable Future Technology Program of the Agency for Defense Development,Republic of Koreasupported by Technology Innovation Program of the Korea Evaluation Institute of Industrial Technology (KEIT) (20016588)funded by Ministry of Trade,Industry and Energy (MOTIE).
文摘The successful utilization of an eco-friendly and biocompatible parylene-C substrate for high-performance solution-processed double-walled carbon nanotube(CNT)electrode-based perovskite solar cells(PSCs)was demonstrated.Through the use of a novel inversion transfer technique,vertical separation of the binders from the CNTs was induced,rendering a stronger p-doping effect and thereby a higher conductivity of the CNTs.The resulting foldable devices exhibited a power conversion efficiency of 18.11%,which is the highest reported among CNT transparent electrode-based PSCs to date,and withstood more than 10,000 folding cycles at a radius of 0.5 mm,demonstrating unprecedented mechanical stability.Furthermore,solar modules were fabricated using entirely laser scribing processes to assess the potential of the solution-processable nanocarbon electrode.Notably,this is the only one to be processed entirely by the laser scribing process and to be biocompatible as well as eco-friendly among the previously reported nonindium tin oxide-based perovskite solar modules.
基金supported by the National Research Foundation(NRF)grant funded by the Korean government(MSIT)(No.RS-2023-00237308).
文摘Artificial sensory systems have emerged as pivotal technologies to bridge the gap between the virtual and real-world,replicating human senses to interact intelligently with external stimuli.To practically apply artificial sensory systems in the real-world,it is essential to mass-produce nanomaterials with ensured sensitivity and selectivity,purify them for desired functions,and integrate them into large-area sensory devices through assembly techniques.A comprehensive understanding of each process parameter from material processing to device assembly is crucial for achieving a high-performing artificial sensory system.This review provides a technological framework for fabricating high-performance artificial sensory systems,covering material processing to device integrations.We introduce recent approaches for dispersing and purifying various nanomaterials including 0D,1D,and 2D nanomaterials.We then highlight advanced coating and printing techniques of the solution-processed nanomaterials based on representative three methods including(i)evaporation-based assembly,(ii)assisted assembly,and(iii)direct patterning.We explore the application and performances of these solution-processed materials and printing methods in fabricating sensory devices mimicking five human senses including vision,olfaction,gustation,hearing,and tactile perception.Finally,we suggest an outlook for possible future research directions to solve the remaining challenges of the artificial sensory systems such as ambient stability,device consistency,and integration with AI-based software.
基金Research funding from the Shanghai Municipal Education Commission in the framework of the oriental scholar and distinguished professor designationfunding from the National Natural Science Foundation of China(NSFC)
文摘Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.
基金We thank the National Natural Science Foundation of China(No.51973122)for financial support.
文摘Solution processability and flexibility still remain major challenges for many thermoelectric(TE)materials,including bismuth telluride(Bi_(2)Te_(3)),a typical and commercially available TE material.Here,we report a new solutionprocessed method to prepare a flexible film of a Bi_(2)Te_(3)/single-walled carbon nanotube(SWCNT)hybrid,where the dissolved Bi_(2)Te_(3) ion precursors are mixed with dispersed SWCNTs in solution and recrystallized on the SWCNT surfaces to form a“cement-rebar”-like architecture.The hybrid film shows an n-type characteristic,with a stable Seebeck coefficient of^(−1)00.00±1.69μVK^(−1) in air.Furthermore,an extremely low in-plane thermal conductivity of∼0.33Wm^(−1) K^(−1) is achieved at 300 K,and the figure of merit(ZT)reaches 0.47±0.02.In addition,the TE performance is independent of mechanical bending.The unique“cement-rebar”-like architecture is believed to be responsible for the excellent TE performances and the high flexibility.The results provide a new avenue for the fabrication of solution-processable and flexible TE hybrid films and will speed up the applications of flexible electronics and energy conversion.
基金Project(11904298)supported by the National Natural Science Foundation of ChinaProject(cstc2020jcyj-msxm X0586)supported by Chongqing Natural Science Foundation,ChinaProject(S202010635001)supported by Chongqing Municipal Training Program of Innovation and Entrepreneurship for Undergraduates,China。
文摘Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state lighting in the future.The TQLED is a multilayer structure device which connects two or more light-emitting units by using an interconnection layer(ICL),which plays an extremely important role in the TQLED.Therefore,realizing an effective ICL is the key to obtain high-efficiency TQLEDs.In this work,the p-type materials polys(3,4-ethylenedioxythiophene),poly(styrenesulfonate)(PEDOT:PSS)and the n-type material zinc magnesium oxide(ZnMgO),were used,and an effective hybrid ICL,the PEDOT:PSS-GO/ZnMgO,was obtained by doping graphene oxide(GO)into PEDOT:PSS.The effect of GO additive on the ICL was systematically investigated.It exhibits that the GO additive brought the fine charge carrier generation and injection capacity simultaneously.Thus,the all solutionprocessed red TQLEDs were prepared and characterized for the first time.The maximum luminance of 40877 cd/m^(2) and the highest current efficiency of 19.6 cd/A were achieved,respectively,showing a 21%growth and a 51%increase when compared with those of the reference device without GO.The encouraging results suggest that our investigation paves the way for efficient all solution-processed TQLEDs.
基金Supported by the National Natural Science Foundation of China under Grant No 61177028
文摘Polymer field-effect transistors operated in the n-channel model with a top-gate/bottom-contact are processed using a solution method. The transistor performance depends on the gate dielectric layer. A high performance polymer transistor is achieved, with the saturated electron mobility of about 0.46cm2/Vs, threshold voltage nearly 0 V and subthreshold sway of about 0.9 V/decade, employing a polystyrene （PS） dielectric layer. The transistor performances are further improved with increasing current and lower operation voltages by utilizing a bi-layer gate dielectric, comprising a thin PS dielectric layer adjacent to the semiconductor to minimize the density of the interface traps for obtaining a small VT, a large μ and a poly（methyl methacrylate） （PMMA） dielectric layer with a relatively high-k adjacent to the gate electrode for enlarging the capacitance, processed from the orthogonal solvents.
基金supported by the National Natural Science Foundation of China(22275003)Shenzhen Fundamental Research Program(JCYJ20200109140425347)+4 种基金the Development and Reform Commission of Shenzhen Municipality(XMHT20200106002)the Key-Area Research and Development Program of Guangdong Province(2019B010924003)Guangdong Basic and Applied Basic Research Foundation(2020B1515120030)provided by Guangdong Key Laboratory of Flexible Optoelectronic Materials and DevicesGuangdong International Science and Technology Cooperation Base of Optoelectronic Materials and Device Technology。
文摘The solution-processed method for organic light-emitting diodes(OLEDs)offers the benefits of cost-effectiveness and enhanced material utilization.In the multilayer architecture of solution-processed OLEDs(SOLEDs),the role of hole-transport materials(HTMs)is pivotal for cascade hole injection.However,commercial HTMs such as poly-(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine)(TFB)are hampered by incompatible energy levels and redissolution with overlayer solvent,prompting the exploration of cross-linkable HTMs(X-HTMs)for better performance.In this study,we have developed two novel small-molecule X-HTMs,N^(1),N^(1)′-((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(N^(4),N^(4)-diphenyl-N^(1)-(4-vinylphenyl)benzene-1,4-diamine)(FTPA-V)and N,N′-((perfluoropropane-2,2-diyl)bis-(4,1-phenylene))bis(9-phenyl-N-(4-vinylphenyl)-9H-carbazol-3-amine)(FPCz-V),which incorporate thermally cross-linkable vinyl groups and electron-rich trifluoromethyl units.The X-HTMs enhance interfacial contact through superior film formation and solvent resistance,along with optimal energy levels.The application of X-HTMs significantly enhances the efficiencies and longevities of blue,green,and red SOLEDs.Specially,blue SOLED incorporating FPCz-V exhibits unprecedented lifetime(LT95)extending to over 150 h,setting a new record for blue SOLEDs.The electrochemistry stability,high bond dissociation energy,and triplet energy levels of X-HTMs can effectively minimize exciton annihilation and prolong the lifetime.These findings underscore the potential of X-HTM optimization to propel the development of stable solution-processed luminescent technologies.
基金the China Scholarship Council(201806890001)support from the Royal Academy of Engineering Enterprise Fellowship (EF2122-13106)EPSRC (EP/W015137/1, EP/W524505/1) for financial support。
文摘The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.
基金the National Natural Science Foundation of China(52103221,52172048,22205130,52063010)Shandong Provincial Natural Science Foundation(ZR2021QB179,ZR2021QB024,ZR2021ZD06)+2 种基金Guangdong Natural Science Foundation of China(2023A1515012323,2023A1515010943,2022A1515110643)the National Key Research and Development Program of China(2022YFB4200400)funded by M0STthe Fundamental Research Funds of Shandong University.
文摘All-solution-processed organic solar cells(OSCs)(from the bottom electrode to the top electrode)are highly attractive thanks to their low cost,lightweight and high-throughput production.However,achieving highly efficient all-solution-processed OSCs remains a significant challenge.One of the key issues is the lack of high-quality solution-processed electrode systems that can replace indium tin oxide(ITO)and vacuum-deposited metal electrodes.In this paper,we comprehensively review recent advances in all-solution-processed osCs,and classified the devices as the top electrode materials,including silver nanowires(AgNWs),conducting polymers and composite conducting materials.The correlation between electrode materials,properties of electrodes,and device performance in all-solution-processed OSCs is elucidated.In addition,the critical roles of the active layer and interface layer are also discussed.Finally,the prospects and challenges of all-solution-processed OSCs are presented.
基金supported by National Natural Science Foundation of China (61861136004)the National Key R&D Program of China (2016YFB0402705)+1 种基金the Innovation Fund of WNLOProgram for HUST Academic Frontier Youth Team (2018QYTD06)
文摘Wearable smart sensors are considered to be the new generation of personal portable devices for health monitoring.By attaching to the skin surface,these sensors are closely related to body signals(such as heart rate,blood oxygen saturation,breath markers,etc.)and ambient signals(such as ultraviolet radiation,inflammable and explosive,toxic and harmful gases),thus providing new opportunities for human activity monitoring and personal telemedicine care.Here we focus on photodetectors and gas sensors built from metal chalcogenide,which have made great progress in recent years.Firstly,we present an overview of healthcare applications based on photodetectors and gas sensors,and discuss the requirement associated with these applications in detail.We then discuss advantages and properties of solution-processable metal chalcogenides,followed by some recent achievements in health monitoring with photodetectors and gas sensors based on metal chalcogenides.Last we present further research directions and challenges to develop an integrated wearable platform for monitoring human activity and personal healthcare.
基金This work was supported by the National Natural Science Foundation of China(Nos.52073282,52122309,21975247,51833009,52261135541)the CAS-Croucher Funding Scheme for Joint Laboratories,the Open Project of the State Key Laboratory of Supramolecular Structure and Materials,China(No.sklssm2023019)the Start-up Scientific Research Foundation from Hainan University,China[No.KYQD(ZR)22174]。
文摘Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs).It is found that the non-conjugated polynorbornenes can keep high triplet energy(ET)levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units,making them capable as host materials for blue emitters.Meanwhile,by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan,the highest occupied molecular orbital(HOMO)levels for the polymer hosts are elevated from-5.50 eV to-5.11 eV,beneficial for reducing the hole injection barrier from anode to emissive layer.As a result,solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain(PNB-TAc)as host and boron,selenium,nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm,full-width at half maximum of 30 nm,together with maximum external quantum efficiency of 20.2%,representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.
基金This research was made possible as a result of a generous grant from the Key Research Program of Frontier Science,the Chinese Academy of Sciences(CAS)(grant no.QYZDJ-SSW-SLH033)the National Natural Science Foundation of China(grant no.52073286)+3 种基金the Natural Science Foundation of Fujian Province(grant no.2006L2005)the Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China(grant nos.2021ZR132 and 2021ZZ115)the Youth Innovation Foundation of Xiamen City(grant nos.3502Z20206082 and 3502Z20206083)the Major Research Project of Xiamen(grant no.3502Z20191015).
文摘Ionic thermally activated delayed fluorescence(TADF)emitters are rarely investigated due to their poor photoluminescence and electroluminescence performance.Herein,highly efficient ionic TADF emitters with charged donor–acceptor(D–A^(+))and D–A^(+)–D architectures are designed,innovatively based on the phosphonium cation electron acceptor.The symmetric D–A^(+)–D compound in doped film exhibits a high photoluminescence quantum yield of 0.91 and a short emission lifetime of 1.43 microseconds.Partially solution-processed organic lightemitting diodes based on these ionic TADF emitters achieve a maximum external quantum efficiency(EQE)of 18.3%and a peak luminance of 14,532 candelas per square meter(cd/m^(2))and show a small efficiency roll-off of 7.1%(EQE=17%)at a practical high luminance of 1000 cd/m^(2).These results demonstrate the high potential of phosphonium cations as promising electron acceptors to construct TADF emitters for high-performance electroluminescence devices.The current study opens up an appealing way for future exploitation of high-efficiency ionic TADF materials.
基金supported by the National Natural Science Foundation of China(52103220,51922021,52273164)the Shandong Provincial Natural Science Foundation(ZR2022ZD37,ZR2019ZD50).
文摘High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.
基金supported by the Major State Basic Research Development Program (No. 2014CB643503)the National Science Foundation for Post-doctoral Scientists of China (No. 2015M580512)partly supported by the program for Innovative Research Team in University of Ministry of Education of China (No. IRT13R54)
文摘A solution-processed CuOx film has been successfully integrated as the hole-transporting layer（HTL） for inverted planar heterojunction perovskite solar cells（PVSCs）. The CuOx layer is fabricated by simply spin-coating a copper acetylacetonate（Cu（acac）2） chloroform solution onto ITO glass with high transparency in the visible range. The compact and pinhole-free perovskite film with large grain domains is grown on the CuOx film. The inverted PVSCs with the structure of ITO/CuOx/MAPbI3/PC（61）BM/ZnO/Al are fabricated and show a best PCE of 17.43% under standard AM 1.5G simulated solar irradiation with a VOCof 1.03 V, aJ（SC） of 22.42 mA cm^（-2）, and a fill factor of 0.76, which is significantly higher and more stable than that fabricated from the often used hole-transporting material PEDOT：PSS（11.98%） under the same experimental conditions. The enhanced performance is attributed to the efficient hole extraction through the CuOx layer as well as the high-quality CH3NH3PbI3 films grown on the CuOx. Our results indicate that low-cost and solution-processed CuOx film is a promising HTL for high performance PVSCs with better stability.
基金financial support by the National Natural Science Foundation of China(21975038,21606039,and 51661135021)the Swiss National Science Foundation(IZLCZ2_170177)+3 种基金the Fundamental Research Funds for the Central Universities(DUT17JC39)the Swedish Foundation for Strategic Research(SSF)the Swedish Energy Agencythe Knut and Alice Wallenberg Foundation。
文摘All-inorganic cesium lead bromide(CsPbBr3)perovskite is attracting growing interest as functional materials in photovoltaics and other optoelectronic devices due to its superb stability.However,the fabrication of high-quality CsPbBr3 films still remains a big challenge by solution-process because of the low solubility of the cesium precursor in common solvents.Herein,we report a facile solution-processed approach to prepare high-quality CsPbBr3 perovskite films via a two-step spin-coating method,in which the Cs Br methanol/H2 O mixed solvent solution is spin-coated onto the lead bromide films,followed by an isopropanol-assisted post-treatment to regulate the crystallization process and to control the film morphology.In this fashion,dense and uniform CsPbBr3 films are obtained consisting of large crystalline domains with sizes up to microns and low defect density.The effectiveness of the resulting CsPbBr3 films is further examined in perovskite solar cells(PSCs)with a simplified planar architecture of fluorine–doped tin oxide/compact Ti O2/CsPbBr3/carbon,which deliver a maximum power conversion efficiency of 8.11%together with excellent thermal and humidity stability.The present work offers a simple and effective strategy in fabrication of high-quality CsPbBr3 films for efficient and stable PSCs as well as other optoelectronic devices.
基金supported by the Natural Science Foundation of SZU (2017003)Shenzhen Science and Technology Research Grant (JCYJ20150324141711684)+2 种基金Singapore National Research Foundation (NRF-RF2009-06)an Investigator-ship Award (NRFNRFI2015-03)Ministry of Education (Singapore) via an AcRF Tier2 Grant (MOE2012-T2-2-086)
文摘The much slower progress in enhancing the thermoelectric performance of n-type Bi2Te3 than that of p-type Bi2Te3 based materials in the past decade hinders the widespread use in power generation and refrigeration. Here, a facile bottom-up solution-synthesis with spark plasma sintering(SPS) process has been developed to build n-type Bi2Te3-xSex bulk nanocomposites, which substantially improves the power factor and decreases the lattice thermal conductivity by tuning the interface scattering of phonons and electrons. The stoichiometric composition in ternary Bi2Te3-xSex nanocomposites is also tuned to optimize the carrier concentration and lattice thermal conductivity. The optimized bulk nanocomposite Bi2Te2.7Se0.3 exhibits a ZT of 1.1 at^371 K, which is comparable to the corresponding commercially available ingots. Our results demonstrate the great potential of the solution-processed n-type Bi2Te3-xSex nanocomposites for cost-effective thermoelectric applications.
基金The authors acknowledge funding from the National Natural Science Foundation of China(61974150 and 51773213)Key Research Program of Frontier Sciences,CAS(QYZDB-SSW-JSC047)+1 种基金the Fundamental Research Funds for the Central Universities,the CAS-EU S&T cooperation partner program(174433KYSB20150013)the Natural Science Foundation of Ningbo(2018A610135).
文摘Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.
基金supported by the National Natural Science Foundation of China(Nos.21772095,91833306,51873159,91956107,61875090 and 21674049)1311 Talents Program of Nanjing University of Posts and Telecommunications(Dingshan),the Six Talent Plan(No.2016XCL050)+3 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,No.YX030003)China Postdoctoral Science Foundation(No.2020M671460)Jiangsu Planned Projects for Postdoctoral Research Funds(No.20202137)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.46030CX17761)。
文摘With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emitting diodes(OLEDs)owing to their thermally activated delayed fluorescence(TADF)nature.However,the highly rigid molecular skeleton with the oppositely positioned bo ron and nitrogen in generating MR effects results in the intrinsic difficulties in the solution-processing of MR-OLEDs.Here,we demonstrate a facile strategy to increase the solubility,enhance the efficiencies and modulate emission color of MR-TADF molecules by extending aromatic rings and introducing tert-butyls into the MR backbone.Two MR-TADF emitters with smaller singlet-triplet splitting energies(ΔE~(ST))and larger oscillator strengths were prepared conveniently,and the solution-processed MR-OLEDs were fabricated for the first time,exhibiting efficient bluish-green electroluminescence with narrow FWHM of 32 nm and external quantum efficiency of 16.3%,which are even comparable to the state-of-the-art performances of the vacuum-evaporated devices.These results prove the feasibility of designing efficient solutionprocessible MR molecules,offering important clues in developing high-performance solution-processed MR-OLEDs with high efficiency and color purity.
基金the National Natural Science Foundation of China(51673097,21875122)Ministry of Science and Technology of China(2016YFA0200200,2019YFA0705903)。
文摘Two-dimensional(2 D)covalent organic frameworks(COFs)with periodic functionalπ-electron systems are an emerging class of optoelectronic materials.However,almost all conjugated COFs so far are insoluble and hard to process,which hampers severely their optoelectronic applications.Here,a solution-processable,nanoscale and sp2 carbon-conjugated COF-like material,PDPP-C20 was successfully designed and synthesized.The solution-processed PDPP-C20 films exhibit high crystallinity and excellent charge transport properties along out-of-plane directions,combined with the highest occupied molecular orbital(HOMO)/lowest unoccupied molecular orbital(LUMO)levels of-5.36/-3.75 e V,making PDPP-C20 suitable for electronic device applications.An efficiency as high as 21.92%has been demonstrated when it was used as a functional interfacial layer in perovskite solar cells,coupled with dramatically improved stability in comparison with the control device due to the superior hydrophobicity of PDPP-C20 layer as well as its passivation effect on perovskite surface.Furthermore,the soluble PDPP-C20 could also be used as donor in bulk-heterojunction organic solar cells and an initial efficiency of 2.46%has been achieved.These results indicate that this new class of soluble and nanoscale COF-like materials should offer a new arena of functional materials for optoelectronic devices.
