Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on ta...Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology,however,exhibiting limited applicability.Therefore,it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor–acceptor compatibilizers,or by introducing another third component.Herein,a unique approach is presented,based on constructing a polymer fiber rigid network with a high glass transition temperature(T_(g))to impede the movement of acceptor and donor molecules,to immobilize the active layer morphology,and thereby to improve thermal stability.A high-T_(g) one-dimensional aramid nanofiber(ANF)is utilized for network construction.Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart.The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart,thereby leaving fundamental processes such as charge separation,transport,and collection,determining the device efficiency,largely unaltered.This strategy is also successfully applied to other photovoltaic systems.The strategy of incorporating a polymer fiber rigid network with high T_(g) offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.展开更多
Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at th...Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.展开更多
Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with hi...Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures,thereby showing strong absorption in visible region.In this work,a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs.Copper(I)thiocyanate(CuSCN)is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility.The transparency of CuSCN benefits high average visible transmittance(AVT)of STOPVs.The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9,and the formed heterojunction exhibits an ability of exciton dissociation.High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination.The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0%with a power conversion efficiency(PCE)of 12.7%.Partial replacement of PM6 with CuSCN leads to a 63%increase in transmittance,resulting in a higher AVT of 30.9%and a comparable PCE of 10.8%.展开更多
Organic photovoltaic devices are on the verge of commercialization with power conversion efficiencies exceeding 10 % in laboratory cells and above 8.5 % in modules. However, one of the main limitations hindering their...Organic photovoltaic devices are on the verge of commercialization with power conversion efficiencies exceeding 10 % in laboratory cells and above 8.5 % in modules. However, one of the main limitations hindering their mass scale production is the debatable inferior stability of organic photovoltaic devices in comparison to other technologies.Adequate donor/acceptor morphology of the active layer is required to provide carrier separation and transport to the electrodes. Unfortunately, the beneficial morphology for device performance is usually a kinetically frozen state which has not reached thermodynamic equilibrium. During the last 5 years, special efforts have been dedicated to isolate the effects related to morphology changes taking place within the active layer and compare to those affecting the interfaces with the external electrodes. The current review discusses some of the factors affecting the donor/acceptor morphology evolution as one of the major intrinsic degradation pathways. Special attention is paid to factors in the nano- and microscale domain.For example, phase segregation of the polymer and fullerene domains due to Ostwald ripening is a major factor in the microscale domain and is affected by the presence of additives, glass transition temperature of the polymers or use of crosslinkers in the active layer. Alternatively, the role of vertical segregation profile toward the external electrodes is key for device operation, being a clear case of nanoscale morphology evolution. For example, donor and acceptor molecules actually present at the external interfaces will determine the leakage current of the device, energy-level alignment, and interfacial recombination processes. Different techniques have been developed over the last few years to understand its relationship with the device efficiency. Of special interest are those techniques which enable in situ analysis being nondestructive as they can be used to study accelerated degradation experiments and some will be discussed here.展开更多
Small molecule organic photovoltaics(SMPVs) were prepared by utilizing liquid crystalline donor material BTR-Cl and two similar optical bandgap non-fullerene acceptor materials BTP-BO-4 F and Y6.The BTPBO-4 F and Y6 h...Small molecule organic photovoltaics(SMPVs) were prepared by utilizing liquid crystalline donor material BTR-Cl and two similar optical bandgap non-fullerene acceptor materials BTP-BO-4 F and Y6.The BTPBO-4 F and Y6 have the similar optical bandgap and different absorption coefficients.The corresponding binary SMPVs exhibit different short circuit current density(/sc)(20.38 vs.23.24 mA cm^(-2)),and fill factor(FF)(70.77% vs.67.21%).A 14.46% power conversion efficiency(PCE) is acquired in ternary SMPVs with 30 wt% Y6,companied with a JSC of 24.17 mA cm^(-2) a FF of 68.78% and an open circuit voltage(Voc) of 0.87 V.The improvement on PCE of ternary SMPVs should originate from the well trade-off between phase separation and photon harvesting of ternary active layers by incorporating 30 wt% Y6 in acceptors.This work may deliver insight onto the improved performance of SMPVs by superposing the superiorities of binary SMPVs with similar optical bandgap acceptors into one ternary cell.展开更多
Organic photovoltaics(OPVs)suitable for application in indoor lighting environments can power a wide range of internet of things(Io T)related electronic devices.The ternary structure has huge advantages in improving t...Organic photovoltaics(OPVs)suitable for application in indoor lighting environments can power a wide range of internet of things(Io T)related electronic devices.The ternary structure has huge advantages in improving the photovoltaic performance of OPVs,including broadening the light absorption,improving the charge transport,manipulating the energy loss(E_(loss))and so on.Herein,we use wide-bandgap photo-active materials,including the benzotriazole-based polymer donor(J52-F),chlorinated polymer donor(PM7)and A_(2)-A_1-D-A_1-A_(2)-structured acceptor(BTA3),to construct ternary OPVs for indoor light applications.Benefitting from the introduction of PM7 as the third component in J52-F:BTA3-based blend,a gratifying PCE of 20.04%with a high V_(OC)of 1.00 V can be obtained under the test conditions with an illumination of 300 lx from an LED lighting source with a color temperature of 3000 K.The excellent device performance is inseparable from the matched spectrum,enhanced light absorption and the reduced E_(loss),while the improved charge transport capability and suppression of carrier recombination also play an indelible role.Our work shows a potential material system to meet the requirement of devices applied under indoor light.Moreover,these findings demonstrate that designing multi-component OPVs is indeed a feasible way to further improve the performances of the photovoltaic energy conversion system for indoor applications.展开更多
Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed...Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed and synthesized through modifying alkyl chains on different nitrogen aromatic rings of the reported non-fullerene acceptor Y11. Although all the molecules have almost similar low band-gap(around 1.30 e V), Y11-M and Y11-EB exhibit wider absorption in 410–870 nm region. Eventually, the conventional devices based on Y11-M and Y11-EB possess more efficient charge generation with low Eloss(around 0.44 e V). In addition, outstanding efficiencies of 16.64% and 17.15% with the fill factor of 76.15% and 74.73% are obtained in PM6:Y11-M and PM6:Y11-EB-based devices, both higher than Y11:PM6. The results highlight the importance of rational alkyl chains optimization, and a good structureproperty relationship is established as well.展开更多
The cost-effective organic semiconductors are strongly needed in organic photovoltaics(OPVs). Herein,two medium bandgap(MBG) electron acceptors, TPT4F and TPT4Cl are developed via the new design of multi-noncovalent i...The cost-effective organic semiconductors are strongly needed in organic photovoltaics(OPVs). Herein,two medium bandgap(MBG) electron acceptors, TPT4F and TPT4Cl are developed via the new design of multi-noncovalent interaction assisted unfused core, flanked with two electron withdrawing end groups. These fullly non-fused MBG acceptors adapt the planar and rigid conformation in solid, therefore exhibiting the ordered face-on stacking and strong photoluminescence in films. As results, TPT4Cl^(-)based OPVs, upon blending with the PBDB-TF polymer donor, have achieved a power conversion efficiency of 10.16% with a low non-radiative loss of 0.27 e V, representing one of the best fullly non-fused medium bandgap acceptors with desirable cost-efficiency balance.展开更多
The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior ...The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior of excitons and charge carriers within the active layer.It is also a key determinant of the photovoltaic performance of the device.During the optimization of OPV devices,the use of additives has been demonstrated to be an effective strategy in microstructure control,leading to enhanced performance.Therefore,the quest for stable and efficient novel additives,along with an exploration and summarization of the mechanisms underlying additive-induced microstructure control,is essential for a better understanding of the developmental trends of high-performance additives.In this review,we categorize additives based on their chemical structures and discuss their effects on the microstructure of the active layer from both thermodynamic and kinetic perspectives.Furthermore,we elaborate on the working mechanisms and their impact on the photovoltaic performance of the devices.This review provides an overview of recent advances in additives for OPVs,offering potential guidance for the future development of additives and further optimization of the active layer in photovoltaic devices.展开更多
Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic ma...Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic materials,especially that of non-fullerene acceptors(NFAs),the OPV field has witnessed rapid progress with power conversion efficiency(PCE)exceeding 19%.However,it remains challenging to overcome the intrinsic trade-off between the photocurrent and photovoltage,restricting the further promotion of the OPV efficiency.In this regard,it is urgent to further tailor the structure of NFAs to broaden their absorption spectra while mitigating the energy loss of relevant devices concomitantly.Heteroatom substitution on the fused-ringπ-core of NFAs is an efficient way to achieve this goal.In addition to improve the nearinfrared light harvest by strengthening the intramolecular charge transfer,it can also enhance the molecular stacking via forming multiple noncovalent interactions,which is favorable for reducing the energetic disorder.Therefore,in this review we focus on the design rules of NFAs,including the polymerized NFAs,of which the core moiety is substituted by various kinds of heteroatoms.We also afford a comprehensive understanding on the structure–propertyperformance relationships of these NFAs.Finally,we anticipate the challenges restricting the efficiency promotion and industrial utilization of OPV,and provide potential solutions based on the further heteroatom optimization on NFA core-moiety.展开更多
Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have be...Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.展开更多
Solution processability is a unique property of organic semiconductors. The compact and regular π-π stacking between molecules is paramount in the performance of organic optoelectronic devices. However, it is still ...Solution processability is a unique property of organic semiconductors. The compact and regular π-π stacking between molecules is paramount in the performance of organic optoelectronic devices. However, it is still a challenge to improve their stacking quality without sacrificing the solution-processability from the aspect of materials design. Here, delicately engineered additives are presented to promote the formation of ordered aggregation of conjugated molecules by regulating their nucleation and growth dynamics. Intriguingly, the long-chain BTP-eC9-4F molecules can realize ordered aggregation comparable to short-chain ones without sacrificing processability. The domain size of BTP-eC9-4F aggregation is enlarged from 24.2 to 32.2 nm in blend films.Thereby exciton diffusion and charge transport become faster, contributing to the suppression of recombination losses. As a result, a power conversion efficiency of 19.2% is achieved in D18:BTP-eC9-4F based organic photovoltaics. Our findings demonstrate a facile strategy to improve the packing quality of solution-processed organic semiconductors for high-efficiency photovoltaics and beyond photovoltaics.展开更多
Organic photovoltaic(OPV) devices hold great promise for indoor light harvesting,offering a theoretical upper limit of power conversion efficiency that surpasses that of other photovoltaic technologies.However,the pre...Organic photovoltaic(OPV) devices hold great promise for indoor light harvesting,offering a theoretical upper limit of power conversion efficiency that surpasses that of other photovoltaic technologies.However,the presence of high leakage currents in OPV devices commonly constrains their effective performance under indoor conditions.In this study,we identified that the origin of the high leakage currents in OPV devices lay in pinhole defects present within the active layer(AL).By integrating an automated spin-coating strategy with sequential deposition processes,we achieved the compactness of the AL and minimized the occurrence of pinhole defects therein.Experimental findings demonstrated that with an increase in the number of deposition cycles,the density of pinhole defects in the AL underwent a marked reduction.Consequently,the leakage current experienced a substantial decrease by several orders of magnitude which achieved through well-calibrated AL deposition procedures.This enabled a twofold enhancement in the power conversion efficiency(PCE) of the OPV devices under conditions of indoor illumination.展开更多
Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(P...Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(PCE)of 15.49%with a short circuit current(JSC)of 24.98 mA cm^-2,an open circuit voltage(VOC)of 0.868 V and a fill factor(FF)of 71.42%.A 16.71%PCE is obtained in the optimized ternary OPVs with PBDB-T-2 Cl:Y6:PC71BM(1:1.2:0.2,wt/wt)active layer,resulting from the synchronously improved JSC of 25.44 mA cm^-2,FF of 75.66%and the constant VOCof 0.868 V.The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation,domain size and molecular arrangement in ternary active layers,which can be confirmed from the characterization on morphology,2 D grazing incidence small and wide-angle X-ray scattering,as well as Raman mapping.In addition,PC71BM may prefer to mix with Y6 to form efficient electron transport channels,which should be conducive to charge transport and collection in the optimized ternary OPVs.This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs,indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting,exciton dissociation and charge transport,while keeping the simple cell fabrication technology.展开更多
The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,ligh...The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.展开更多
High-performance donor-acceptor electron acceptors containing 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile(INCN)-type terminals are labile toward photooxidation and basic conditions,and new molecular designs ...High-performance donor-acceptor electron acceptors containing 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile(INCN)-type terminals are labile toward photooxidation and basic conditions,and new molecular designs toward electron acceptors that can achieve both high power conversion efficiencies and high stability are urgently needed.By replacing the central benzene ring in the classical ladder-type n-type semiconductor,2,2′-(indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile,with the electron-rich 4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene,we report herein the design of 2,2′-(7,7,15,15-tetrahexyl-7,15-dihydro-sindaceno[1,2-b:5,6-b′]diindeno[1,2-d]thiophene-2,10(2H)-diylidene)dimalononitrile(ITYM),a new type of all-fused-ring electron acceptor(AFRA).A threestep reaction including a key Pd-catalyzed double C-H activation/intramolecular cyclization is established for the efficient synthesis of such type of electron acceptors.ITYM is confirmed by singlecrystal X-ray analysis,which shows a planar nonacyclic structure with strongπ-πstacking.Compared with the classical carbon-bridged INCN-type acceptors,ITYM exhibits extraordinary stability with very promising performance.The AFRA concept opens a new avenue toward high-efficiency and-stability organic photovoltaics(OPVs).展开更多
Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film ...Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.展开更多
Ternary organic photovoltaic(OPV)strategy is an effective but facile approach to enhance the photovoltaic performance for single-junction devices.Herein,a series of ternary OPVs were fabricated by employing a wide ban...Ternary organic photovoltaic(OPV)strategy is an effective but facile approach to enhance the photovoltaic performance for single-junction devices.Herein,a series of ternary OPVs were fabricated by employing a wide bandgap donor(PBDB-TF)and two acceptor-donor-acceptor(A-D-A)-type nonfullerene small molecule acceptors(NF-SMAs,called F-2 Cl and 3 TT-OCIC).As the third component,the near-infrared SMA,3 TT-OCIC,has complementary absorption spectrum,narrow bandgap and wellcompatible crystallization property to the host acceptor(F-2 Cl)for efficient ternary OPVs.With these,the optimal ternary devices yield significantly enhanced power conversion efficiency of 15.23%,one of the very few examples with PCE higher than15%other than Y6 systems.This is mainly attributed to the increased short-circuit current density of 24.92 m A cm^(-2) and dramatically decreased energy loss of 0.53 e V.This work presents a successful example for simultaneously improving current,minimizing energy loss and together with modifying the morphology of active layers in OPVs,which will contribute to the further construction of high performance ternary OPVs.展开更多
Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fulleren...Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fullerene acceptor ITIC reported in 2015.The highest power conversion efficiency(PCE)is currently above 18%for OPV.However,there are still imparities in the efficiency of OPVs when compared with silicon-based photovoltaics,as well as in their shelf life.Compared with inorganicbased photovoltaics,the efficiency of large-area OPVs is lower and the life time of OPVs is shorter.Therefore,such inferior performance of large-area OPVs restricts the commercial development.Based on these constraints,this paper reviews the research work regarding OPVs into three aspects:stability,encapsulation technology,and recent large-area preparation technologies.展开更多
Ternary strategy is one of the most effective methods to further boost the power conversion efficiency(PCE)of organic photovoltaic cells(OPVs).In terms of high-efficiency PM6:Y6 binary systems,there is still room to f...Ternary strategy is one of the most effective methods to further boost the power conversion efficiency(PCE)of organic photovoltaic cells(OPVs).In terms of high-efficiency PM6:Y6 binary systems,there is still room to further reduce energy_(loss)(E_(loss))through regulating molecular packing and aggregation by introducing a third component in the construction of ternary OPVs.Here we introduce a simple molecule BR1 based on an acceptor-donor-acceptor(A-D-A)structure with a wide bandgap and high crystallinity into PM6:Y6-based OPVs.It is proved that BR1 can be selectively dispersed into the donor phase in the PM6:Y6 and reduce disorder in the ternary blends,thus resulting in lower E_(loss,non-rad)and E_(loss).Furthermore,the mechanism study reveals well-develop phase separation morphology and complemented absorption spectra in the ternary blends,leading to higher charge mobility,suppressed recombination,which concurrently contributes to the significantly improved PCE of 17.23%for the ternary system compared with the binary ones(16.21%).This work provides an effective approach to improve the performance of the PM6:Y6-based OPVs by adopting a ternary strategy with a simple molecule as the third component.展开更多
基金financially supported by the Sichuan Science and Technology Program(Grant Nos.2023YFH0087,2023YFH0085,2023YFH0086,and 2023NSFSC0990)State Key Laboratory of Polymer Materials Engineering(Grant Nos.sklpme2022-3-02 and sklpme2023-2-11)+1 种基金Tibet Foreign Experts Program(Grant No.2022wz002)supported by the King Abdullah University of Science and Technology(KAUST)Office of Research Administration(ORA)under Award Nos.OSR-CARF/CCF-3079 and OSR-2021-CRG10-4701.
文摘Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology,however,exhibiting limited applicability.Therefore,it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor–acceptor compatibilizers,or by introducing another third component.Herein,a unique approach is presented,based on constructing a polymer fiber rigid network with a high glass transition temperature(T_(g))to impede the movement of acceptor and donor molecules,to immobilize the active layer morphology,and thereby to improve thermal stability.A high-T_(g) one-dimensional aramid nanofiber(ANF)is utilized for network construction.Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart.The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart,thereby leaving fundamental processes such as charge separation,transport,and collection,determining the device efficiency,largely unaltered.This strategy is also successfully applied to other photovoltaic systems.The strategy of incorporating a polymer fiber rigid network with high T_(g) offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00213920,NRF-2021R1A4A1031761).
文摘Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.
基金financially supported by the Sichuan Science and Technology Program (2023YFH0086, 2023YFH0085, 2023YFH0087 and 2023NSFSC0990)the State Key Laboratory of Polymer Materials Engineering (sklpme2022-3-02 and sklpme2023-2-11)the Tibet Foreign Experts Program (2022wz002)
文摘Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures,thereby showing strong absorption in visible region.In this work,a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs.Copper(I)thiocyanate(CuSCN)is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility.The transparency of CuSCN benefits high average visible transmittance(AVT)of STOPVs.The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9,and the formed heterojunction exhibits an ability of exciton dissociation.High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination.The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0%with a power conversion efficiency(PCE)of 12.7%.Partial replacement of PM6 with CuSCN leads to a 63%increase in transmittance,resulting in a higher AVT of 30.9%and a comparable PCE of 10.8%.
基金supported by FP7 European collaborative project SUNFLOWER(FP7-ICT-2011-7contract No.287594)the Spanish Ministerio de Economía y Competitividad(project MAT2013-47192-C3-1-R)+1 种基金Generalitat Valenciana(project ISIC/2012/008 Institute of Nanotechnologies for Clean Energies)the Spanish Ministerio de Economía y Competitividad for a Ramón y Cajal Fellowship(RYC2014-16809)
文摘Organic photovoltaic devices are on the verge of commercialization with power conversion efficiencies exceeding 10 % in laboratory cells and above 8.5 % in modules. However, one of the main limitations hindering their mass scale production is the debatable inferior stability of organic photovoltaic devices in comparison to other technologies.Adequate donor/acceptor morphology of the active layer is required to provide carrier separation and transport to the electrodes. Unfortunately, the beneficial morphology for device performance is usually a kinetically frozen state which has not reached thermodynamic equilibrium. During the last 5 years, special efforts have been dedicated to isolate the effects related to morphology changes taking place within the active layer and compare to those affecting the interfaces with the external electrodes. The current review discusses some of the factors affecting the donor/acceptor morphology evolution as one of the major intrinsic degradation pathways. Special attention is paid to factors in the nano- and microscale domain.For example, phase segregation of the polymer and fullerene domains due to Ostwald ripening is a major factor in the microscale domain and is affected by the presence of additives, glass transition temperature of the polymers or use of crosslinkers in the active layer. Alternatively, the role of vertical segregation profile toward the external electrodes is key for device operation, being a clear case of nanoscale morphology evolution. For example, donor and acceptor molecules actually present at the external interfaces will determine the leakage current of the device, energy-level alignment, and interfacial recombination processes. Different techniques have been developed over the last few years to understand its relationship with the device efficiency. Of special interest are those techniques which enable in situ analysis being nondestructive as they can be used to study accelerated degradation experiments and some will be discussed here.
基金the financial supporting from the NSFC(61975006,61675017)NSFRPSI(Y72Z090Q10)+3 种基金the NSFCQ(cstc2019jcyj-msxm X0400)the NYTPP(R52A199Z11)the YIPACAS(E0296104)the BNSF(4192049)。
文摘Small molecule organic photovoltaics(SMPVs) were prepared by utilizing liquid crystalline donor material BTR-Cl and two similar optical bandgap non-fullerene acceptor materials BTP-BO-4 F and Y6.The BTPBO-4 F and Y6 have the similar optical bandgap and different absorption coefficients.The corresponding binary SMPVs exhibit different short circuit current density(/sc)(20.38 vs.23.24 mA cm^(-2)),and fill factor(FF)(70.77% vs.67.21%).A 14.46% power conversion efficiency(PCE) is acquired in ternary SMPVs with 30 wt% Y6,companied with a JSC of 24.17 mA cm^(-2) a FF of 68.78% and an open circuit voltage(Voc) of 0.87 V.The improvement on PCE of ternary SMPVs should originate from the well trade-off between phase separation and photon harvesting of ternary active layers by incorporating 30 wt% Y6 in acceptors.This work may deliver insight onto the improved performance of SMPVs by superposing the superiorities of binary SMPVs with similar optical bandgap acceptors into one ternary cell.
基金supported by the National Natural Science Foundation of China(51873007,51961165102,and 21835006)the Fundamental Research Funds for the Central Universities in China(2019MS025,2018MS032,2017MS027,2017XS084)。
文摘Organic photovoltaics(OPVs)suitable for application in indoor lighting environments can power a wide range of internet of things(Io T)related electronic devices.The ternary structure has huge advantages in improving the photovoltaic performance of OPVs,including broadening the light absorption,improving the charge transport,manipulating the energy loss(E_(loss))and so on.Herein,we use wide-bandgap photo-active materials,including the benzotriazole-based polymer donor(J52-F),chlorinated polymer donor(PM7)and A_(2)-A_1-D-A_1-A_(2)-structured acceptor(BTA3),to construct ternary OPVs for indoor light applications.Benefitting from the introduction of PM7 as the third component in J52-F:BTA3-based blend,a gratifying PCE of 20.04%with a high V_(OC)of 1.00 V can be obtained under the test conditions with an illumination of 300 lx from an LED lighting source with a color temperature of 3000 K.The excellent device performance is inseparable from the matched spectrum,enhanced light absorption and the reduced E_(loss),while the improved charge transport capability and suppression of carrier recombination also play an indelible role.Our work shows a potential material system to meet the requirement of devices applied under indoor light.Moreover,these findings demonstrate that designing multi-component OPVs is indeed a feasible way to further improve the performances of the photovoltaic energy conversion system for indoor applications.
基金support of the National Natural Science Foundation of China (21875286)the National Key Research and Development Program of China (2017YFA0206600)。
文摘Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed and synthesized through modifying alkyl chains on different nitrogen aromatic rings of the reported non-fullerene acceptor Y11. Although all the molecules have almost similar low band-gap(around 1.30 e V), Y11-M and Y11-EB exhibit wider absorption in 410–870 nm region. Eventually, the conventional devices based on Y11-M and Y11-EB possess more efficient charge generation with low Eloss(around 0.44 e V). In addition, outstanding efficiencies of 16.64% and 17.15% with the fill factor of 76.15% and 74.73% are obtained in PM6:Y11-M and PM6:Y11-EB-based devices, both higher than Y11:PM6. The results highlight the importance of rational alkyl chains optimization, and a good structureproperty relationship is established as well.
基金funded by the National Natural Science Foundation of China(22125901 and 21722404)the Research Grants Council(RGC)of Hong Kong(General Research Fund(14303519)+3 种基金the Joint Laboratory Funding Scheme Project(JLFS/P-102/18)the NSFC/RGC Joint Research Scheme Grant(NCUHK418/17))the CUHK direct grant(4442384)the beam time and technical support provided by Chun-Jen Su and U-Ser Jeng form Synchrotron Radiation Research Center,Hsinchu Science Park,Taiwan,China。
文摘The cost-effective organic semiconductors are strongly needed in organic photovoltaics(OPVs). Herein,two medium bandgap(MBG) electron acceptors, TPT4F and TPT4Cl are developed via the new design of multi-noncovalent interaction assisted unfused core, flanked with two electron withdrawing end groups. These fullly non-fused MBG acceptors adapt the planar and rigid conformation in solid, therefore exhibiting the ordered face-on stacking and strong photoluminescence in films. As results, TPT4Cl^(-)based OPVs, upon blending with the PBDB-TF polymer donor, have achieved a power conversion efficiency of 10.16% with a low non-radiative loss of 0.27 e V, representing one of the best fullly non-fused medium bandgap acceptors with desirable cost-efficiency balance.
基金supported by the National Natural Science Foundation of China(Nos.52303226,21971049)Zhejiang Provincial Natural Science Foundation(Nos.LQ23E030002,LZ23B040001)“Ten-thousand Talents Plan”of Zhejiang Province(No.2019R52040)。
文摘The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior of excitons and charge carriers within the active layer.It is also a key determinant of the photovoltaic performance of the device.During the optimization of OPV devices,the use of additives has been demonstrated to be an effective strategy in microstructure control,leading to enhanced performance.Therefore,the quest for stable and efficient novel additives,along with an exploration and summarization of the mechanisms underlying additive-induced microstructure control,is essential for a better understanding of the developmental trends of high-performance additives.In this review,we categorize additives based on their chemical structures and discuss their effects on the microstructure of the active layer from both thermodynamic and kinetic perspectives.Furthermore,we elaborate on the working mechanisms and their impact on the photovoltaic performance of the devices.This review provides an overview of recent advances in additives for OPVs,offering potential guidance for the future development of additives and further optimization of the active layer in photovoltaic devices.
基金City University of Hong Kong,Grant/Award Number:9380086Innovation and Technology Commission of Hong Kong,Grant/Award Numbers:GHP/018/20SZ,MRP/040/21X+3 种基金Environment and Ecology Bureau of Hong Kong,Grant/Award Number:202020164Research Grants Council of Hong Kong,Grant/Award Numbers:11307621,C6023-19GFShenzhen Science and Technology Program,Grant/Award Number:SGDX20201103095412040Guangdong Major Project of Basic and Applied Basic Research,Grant/Award Number:2019B030302007。
文摘Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic materials,especially that of non-fullerene acceptors(NFAs),the OPV field has witnessed rapid progress with power conversion efficiency(PCE)exceeding 19%.However,it remains challenging to overcome the intrinsic trade-off between the photocurrent and photovoltage,restricting the further promotion of the OPV efficiency.In this regard,it is urgent to further tailor the structure of NFAs to broaden their absorption spectra while mitigating the energy loss of relevant devices concomitantly.Heteroatom substitution on the fused-ringπ-core of NFAs is an efficient way to achieve this goal.In addition to improve the nearinfrared light harvest by strengthening the intramolecular charge transfer,it can also enhance the molecular stacking via forming multiple noncovalent interactions,which is favorable for reducing the energetic disorder.Therefore,in this review we focus on the design rules of NFAs,including the polymerized NFAs,of which the core moiety is substituted by various kinds of heteroatoms.We also afford a comprehensive understanding on the structure–propertyperformance relationships of these NFAs.Finally,we anticipate the challenges restricting the efficiency promotion and industrial utilization of OPV,and provide potential solutions based on the further heteroatom optimization on NFA core-moiety.
基金funded by National Natural Science Foundation of China (No.22125901)the National Key Research and Development Program of China (No.2019YFA0705900)the Fundamental Research Funds for the Central Universities (No.226–2023–00113)。
文摘Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.
基金supported by the National Natural Science Foundation of China(52303239)the Natural Science Foundation of Shandong Province(ZR2022QB141,2023HWYQ-087)+1 种基金Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University(KJS2209)Sichuan Science and Technology Program(2023NSFSC0990)。
文摘Solution processability is a unique property of organic semiconductors. The compact and regular π-π stacking between molecules is paramount in the performance of organic optoelectronic devices. However, it is still a challenge to improve their stacking quality without sacrificing the solution-processability from the aspect of materials design. Here, delicately engineered additives are presented to promote the formation of ordered aggregation of conjugated molecules by regulating their nucleation and growth dynamics. Intriguingly, the long-chain BTP-eC9-4F molecules can realize ordered aggregation comparable to short-chain ones without sacrificing processability. The domain size of BTP-eC9-4F aggregation is enlarged from 24.2 to 32.2 nm in blend films.Thereby exciton diffusion and charge transport become faster, contributing to the suppression of recombination losses. As a result, a power conversion efficiency of 19.2% is achieved in D18:BTP-eC9-4F based organic photovoltaics. Our findings demonstrate a facile strategy to improve the packing quality of solution-processed organic semiconductors for high-efficiency photovoltaics and beyond photovoltaics.
基金Fundamental Research Funds for the Central Universities,China (No. 2232022A13)。
文摘Organic photovoltaic(OPV) devices hold great promise for indoor light harvesting,offering a theoretical upper limit of power conversion efficiency that surpasses that of other photovoltaic technologies.However,the presence of high leakage currents in OPV devices commonly constrains their effective performance under indoor conditions.In this study,we identified that the origin of the high leakage currents in OPV devices lay in pinhole defects present within the active layer(AL).By integrating an automated spin-coating strategy with sequential deposition processes,we achieved the compactness of the AL and minimized the occurrence of pinhole defects therein.Experimental findings demonstrated that with an increase in the number of deposition cycles,the density of pinhole defects in the AL underwent a marked reduction.Consequently,the leakage current experienced a substantial decrease by several orders of magnitude which achieved through well-calibrated AL deposition procedures.This enabled a twofold enhancement in the power conversion efficiency(PCE) of the OPV devices under conditions of indoor illumination.
基金supported by the National Natural Science Foundation of China(61675017)Beijing Natural Science Foundation(4192049)
文摘Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(PCE)of 15.49%with a short circuit current(JSC)of 24.98 mA cm^-2,an open circuit voltage(VOC)of 0.868 V and a fill factor(FF)of 71.42%.A 16.71%PCE is obtained in the optimized ternary OPVs with PBDB-T-2 Cl:Y6:PC71BM(1:1.2:0.2,wt/wt)active layer,resulting from the synchronously improved JSC of 25.44 mA cm^-2,FF of 75.66%and the constant VOCof 0.868 V.The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation,domain size and molecular arrangement in ternary active layers,which can be confirmed from the characterization on morphology,2 D grazing incidence small and wide-angle X-ray scattering,as well as Raman mapping.In addition,PC71BM may prefer to mix with Y6 to form efficient electron transport channels,which should be conducive to charge transport and collection in the optimized ternary OPVs.This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs,indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting,exciton dissociation and charge transport,while keeping the simple cell fabrication technology.
基金Foundation of Guangzhou Science and Technology Project,Grant/Award Number:201707020019Natural Science Foundation of China,Grant/Award Numbers:21520102006,21634004。
文摘The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.
基金The authors thank the National Key R&D Program of China(nos.2019YFA0705900 and 2017YFA0204701)the National Natural Science Foundation of China(nos.21661132006 and 91833304)for their financial support。
文摘High-performance donor-acceptor electron acceptors containing 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile(INCN)-type terminals are labile toward photooxidation and basic conditions,and new molecular designs toward electron acceptors that can achieve both high power conversion efficiencies and high stability are urgently needed.By replacing the central benzene ring in the classical ladder-type n-type semiconductor,2,2′-(indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile,with the electron-rich 4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene,we report herein the design of 2,2′-(7,7,15,15-tetrahexyl-7,15-dihydro-sindaceno[1,2-b:5,6-b′]diindeno[1,2-d]thiophene-2,10(2H)-diylidene)dimalononitrile(ITYM),a new type of all-fused-ring electron acceptor(AFRA).A threestep reaction including a key Pd-catalyzed double C-H activation/intramolecular cyclization is established for the efficient synthesis of such type of electron acceptors.ITYM is confirmed by singlecrystal X-ray analysis,which shows a planar nonacyclic structure with strongπ-πstacking.Compared with the classical carbon-bridged INCN-type acceptors,ITYM exhibits extraordinary stability with very promising performance.The AFRA concept opens a new avenue toward high-efficiency and-stability organic photovoltaics(OPVs).
基金supported by the National Natural Science Foundation of China(51903189,51800334)。
文摘Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.
基金supported by the National Key Research and Development Program of China(2019YFA0705900,2016YFA0200200)the National Natural Science Foundation of China(21935007,51873089,51773095)+1 种基金Tianjin city(20JCZDJC00740,17JCJQJC44500)111 Project(B12015)。
文摘Ternary organic photovoltaic(OPV)strategy is an effective but facile approach to enhance the photovoltaic performance for single-junction devices.Herein,a series of ternary OPVs were fabricated by employing a wide bandgap donor(PBDB-TF)and two acceptor-donor-acceptor(A-D-A)-type nonfullerene small molecule acceptors(NF-SMAs,called F-2 Cl and 3 TT-OCIC).As the third component,the near-infrared SMA,3 TT-OCIC,has complementary absorption spectrum,narrow bandgap and wellcompatible crystallization property to the host acceptor(F-2 Cl)for efficient ternary OPVs.With these,the optimal ternary devices yield significantly enhanced power conversion efficiency of 15.23%,one of the very few examples with PCE higher than15%other than Y6 systems.This is mainly attributed to the increased short-circuit current density of 24.92 m A cm^(-2) and dramatically decreased energy loss of 0.53 e V.This work presents a successful example for simultaneously improving current,minimizing energy loss and together with modifying the morphology of active layers in OPVs,which will contribute to the further construction of high performance ternary OPVs.
基金supported by the National Key R&D Program of“Strategic Advanced Electronic Materials”(2016YFB0401100)the National Natural Science Foundation of China(61574077)+1 种基金the Major Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(19KJA460005)the Natural Science Foundation of Jiangsu Province(BK20170961)。
文摘Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fullerene acceptor ITIC reported in 2015.The highest power conversion efficiency(PCE)is currently above 18%for OPV.However,there are still imparities in the efficiency of OPVs when compared with silicon-based photovoltaics,as well as in their shelf life.Compared with inorganicbased photovoltaics,the efficiency of large-area OPVs is lower and the life time of OPVs is shorter.Therefore,such inferior performance of large-area OPVs restricts the commercial development.Based on these constraints,this paper reviews the research work regarding OPVs into three aspects:stability,encapsulation technology,and recent large-area preparation technologies.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.22005234 and 61904134)Zhejiang Lab(No.2021MC0AB02).
文摘Ternary strategy is one of the most effective methods to further boost the power conversion efficiency(PCE)of organic photovoltaic cells(OPVs).In terms of high-efficiency PM6:Y6 binary systems,there is still room to further reduce energy_(loss)(E_(loss))through regulating molecular packing and aggregation by introducing a third component in the construction of ternary OPVs.Here we introduce a simple molecule BR1 based on an acceptor-donor-acceptor(A-D-A)structure with a wide bandgap and high crystallinity into PM6:Y6-based OPVs.It is proved that BR1 can be selectively dispersed into the donor phase in the PM6:Y6 and reduce disorder in the ternary blends,thus resulting in lower E_(loss,non-rad)and E_(loss).Furthermore,the mechanism study reveals well-develop phase separation morphology and complemented absorption spectra in the ternary blends,leading to higher charge mobility,suppressed recombination,which concurrently contributes to the significantly improved PCE of 17.23%for the ternary system compared with the binary ones(16.21%).This work provides an effective approach to improve the performance of the PM6:Y6-based OPVs by adopting a ternary strategy with a simple molecule as the third component.
