Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other wor...Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.展开更多
A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles compos...A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions.Synthetic PbI_(2)was successfully applied for preparation of perovskite precursors to fabricate solar cells.This regulation of ChiSifiCa on PbI_(2)improves the power conversion efficiency of corresponding perovskite solar cells to 16%.The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.展开更多
Formamidinium lead triiodide(FAPbI_(3))is a research hotspot in perovskite photovoltaics due to its broad light absorption and proper thermal stability.However,quite a few researches focused on the stability of the FA...Formamidinium lead triiodide(FAPbI_(3))is a research hotspot in perovskite photovoltaics due to its broad light absorption and proper thermal stability.However,quite a few researches focused on the stability of the FAPbI_(3) perovskite precursor solutions.Besides,the most efficient FAPbI_(3) layers are prepared by the spin-coating method,which is limited to the size of the device.Herein,the stability of FAPbI_(3) perovskite solution with methylammonium chloride(MACl)or cesium chloride(CsCl)additive is studied for preparing perovskite film through an upscalable blade-coating method.Each additive works well for achieving a high-quality FAPbI_(3) film,resulting in efficient carbon electrode perovskite solar cells(pero-SCs)in the ambient condition.However,the perovskite solution with MACl additive shows poor aging stability that noα-FAPbI_(3) phase is observed when the solution is aged over one week.While the perovskite solution with CsCl additive shows promising aging stability that it still forms high-quality pureα-FAPbI_(3) perovskite film even the solution is aged over one month.During the solution aging process,the MACl could be decomposed into methylamine which will form some unfavored intermediated phase inducingδ-phase FAPbI_(3).Whereas,replacing MACl with CsCl could effectively solve this issue.Our founding shows that there is a great need to develop a non-MACl FAPbI_(3) perovskite precursor solution for cost-effective preparation of pero-SCs.展开更多
Formamidinium lead iodide(FAPbI3)is a newly developed hybrid perovskite that potentially can be used in high-efficiency solution-processed solar cells.Here,the temperature-dependent dynamic optical properties of three...Formamidinium lead iodide(FAPbI3)is a newly developed hybrid perovskite that potentially can be used in high-efficiency solution-processed solar cells.Here,the temperature-dependent dynamic optical properties of three types of FAPbI3 perovskite films(fabricated using three different precursor systems)are comparatively studied.The time-resolved photoluminescence(PL)spectra reveal that FAPbI3 films made from the new precursor(a mixture of formamidinium iodide and hydrogen lead triiodide)exhibit the longest lifetime of 439 ns at room temperature,suggesting a lower number of defects and lower non-radiative recombination losses compared with FAPbI3 obtained from the other two precursors.From the temperature-dependent PL spectra,a phase transition in the films is clearly observed.Meanwhile,exciton-binding energies of 8.1 and 18 meV for the high-and lowtemperature phases are extracted,respectively.Importantly,the PL spectra for all of the samples show a single peak at room temperature,whereas at liquid-helium temperature the emission features two peaks:one in higher energy displaying a fast decay(0.5 ns)and a second red-shifted peak with a decay of up to several microseconds.These two emissions,separated by~18 meV,are attributed to free excitons and bound excitons with singlet and triplet characters,respectively.展开更多
SiO2 nanoparticles were used to regulate the crystallizing process of lead halide perovskite films prepared by the sequential deposition method,which was used in the low-temperature-processed,carbon-electrode-basing,h...SiO2 nanoparticles were used to regulate the crystallizing process of lead halide perovskite films prepared by the sequential deposition method,which was used in the low-temperature-processed,carbon-electrode-basing,hole-conductor-free planar perovskite solar cells.It was observed that,after adding small amount of SiO2 precursor(1 vol%)into the lead iodide solution,performance parameters of open-circuit voltage,short-circuit current and fill factor were all upgraded,which helped to increase the power conversion efficiency(reverse scan)from 11.44(±1.83)%(optimized at 12.42%)to 14.01(±2.14)%(optimized at 15.28%,AM 1.5G,100 mW/cm^2).Transient photocurrent decay curve measurements showed that,after the incorporation of SiO2 nanoparticles,charge extraction was accelerated,while transient photovoltage decay and dark current curve tests both showed that recombination was retarded.The improvement is due to the improved crystallinity of the perovskite film.X-ray diffraction and scanning electron microscopy studies observed that,with incorporation of amorphous SiO2 nanoparticles,smaller crystallites were obtained in lead iodide films,while larger crystallites were achieved in the final perovskite film.This study implies that amorphous SiO2 nanoparticles could regulate the coarsening process of the perovskite film,which provides an effective method in obtaining high quality perovskite film.展开更多
Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) solar cell devices was performed by using iso-butyl ammonium iodide(IBA)passivated on Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) films.The n-i-p structure of pero...Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) solar cell devices was performed by using iso-butyl ammonium iodide(IBA)passivated on Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) films.The n-i-p structure of perovskite solar cell devices was fabricated with the structure of FTO/SnO_(2)/Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3)(FTO,i.e.,fluorine doped tin oxide)and IBA/Spiro-OMeTAD/Ag.The effect of different weights of IBA passivated on Cs-doped perovskite solar cells(PSCs)was systematically investigated and compared with non-passivated devices.It was found that the 5-mg IBA-passivated devices exhibited a high power conversion efficiency(PCE)of 15.49%higher than 12.64%of non-IBA-passivated devices.The improvement of photovoltaic parameters of the 5-mg IBA-passivated device can be clearly observed compared to the Cs-doped device.The better performance of the IBA-passivated device can be confirmed by the reduction of PbI_(2) phase in the crystal structure,lower charge recombination rate,lower charge transfer resistance,and improved contact angle of perovskite films.Therefore,IBA passivation on Cs_(0.1)(CH_(3)NH)_(0.9)PbI_(3) is a promising technique to improve the efficiency of Cs-doped perovskite solar cells.展开更多
Previous reports of formamidinium/methylamine(FAMA)-mixed halide perovskite solar cells have focused mainly on controlling the morphology of the perovskite film and its interface—for example,through the inclusion of ...Previous reports of formamidinium/methylamine(FAMA)-mixed halide perovskite solar cells have focused mainly on controlling the morphology of the perovskite film and its interface—for example,through the inclusion of bromine and surface passivation.In this paper,we describe a new processing pathway for the growth of a high-quality bromine-free FAMAPbI3 halide perovskites via the control of intermediate phase.Through low-temperature aging growth(LTAG)of a freshly deposited perovskite film,α-phase perovskites can be seeded in the intermediate phase and,at the same time,prevent beta-phase perovskite to nucleate.After postannealing,large grain-size perovskites with significantly reduced PbI2 presence on the surface can be obtained,thereby eliminating the need of additional surface passivation step.Our pristine LTAG-treated solar cells could provide PCEs of greater than 22%without elaborate use of bromine or an additional passivation layer.More importantly,when using this LTAG process,the growth of the pure alpha-phase FAMAPbI3 was highly reproducible.展开更多
Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation fun...Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation functionals,such as local density approximation,grand gradient approximation(GGA),and hybrid functionals,either underestimate band gaps or misplace defect levels.In this study,we revisited iodine defects in CH_(3)NH_(3)PbI_(3) by combining the accuracy of total energy calculations of GGA and single-electron level calculation of the GW method.The combined approach predicted neutral Im_(i) to be unstable and the transition level of Im_(i)(+1/-1)to be close to the valence band maximum.Therefore,Im_(i) may not be as detrimental as previously reported.Moreover,Vm I may be unstable in the-1 charged state but could still be detrimental owing to the deep transition level of Vm I(+1/0).These results could facilitate the further understanding of the intrinsic point defect and defect passivation observed in CH_(3)NH_(3)PbI_(3).展开更多
A new lead（Ⅱ） iodide coordination polymer [（npq）（PbI3）]n1 （npq = N-propyl- quinolinium） has been synthesized in the presence of npq as structure-directing reagent （SDA）. Compound 1 crystallizes in the ortho...A new lead（Ⅱ） iodide coordination polymer [（npq）（PbI3）]n1 （npq = N-propyl- quinolinium） has been synthesized in the presence of npq as structure-directing reagent （SDA）. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 19.158（4）, b = 7.9909（16）, c = 22.929（5） A, V = 3510.2（12） A3, Z = 8, Dc = 2.877 g/cm3, F（000） = 2672, C12H1413NPb, Mr= 760.14, μ（MoKα） = 14.872 mm-1, the final R = 0.0431 and wR = 0.1021 for 3678 observed reflections with Ⅰ 〉 2σ（Ⅰ）. Structure determination indicates that the [PbI3]^-n infinite chains in each unit cell shape the sketch of 1, which could be described as the result of face-sharing distorted PbI6 octahedra running along the b axis. Electrostatic interaction between conjugated organic counter-cations and inorganic moieties presents and contributes to the crystal packing. 1 was further characterized with IR and elemental analysis. Based on the crystal structure data, quantum chemical calculation with DFT method was used to reveal the electronic structure and optical property of 1.展开更多
The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the ap...The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.展开更多
A new iodiplumbate polymer [（AOD）（Pb216）]n 1 （AOD = O-protonated 4-azonia-7- oxaspiro（4,5） decane quaternary ammonium） was synthesized by self-assembly reaction of AOD-I, Pb（NO3）2 and NaI, and structurally d...A new iodiplumbate polymer [（AOD）（Pb216）]n 1 （AOD = O-protonated 4-azonia-7- oxaspiro（4,5） decane quaternary ammonium） was synthesized by self-assembly reaction of AOD-I, Pb（NO3）2 and NaI, and structurally determined. Compound 1 crystallizes in the hexagonal system, space group P3, with a = 18.2704（8）, c = 8.1663（6） A, V= 2360.8（2） A3, Z = 3, De = 2.783 g/cm^3, F（000） = 1686, C8H17I6NOPb2, Mr = 1319.03, μ（MoKa） = 16.562 mm^-1, the final R = 0.0535 and wR = 0.1793 for 4943 observed reflections with I 〉 2σ（I）. In compound 1, three independent （PbEI6）^2-n infinite chains in each unit cell shape the sketch of compound 1 under the template of AOD-H^2＋ cation. Each （PbaI6）^2-n chain generates from the face-sharing of distorted PbI6 octahedra. （PbEI6）^2-n polyanions interact with AOD-H^2＋ cations by electrostatic interaction in the crystal to feature a so-called hybrid structure. Compound 1 was further characterized with IR, elemental analysis, fluorescence spectrum and thermal analysis. Based on the crystal structure data, DFT calculation was carried out to reveal the electronic structure of compound 1.展开更多
Organic–inorganic hybrid perovskites are quite promising candidates in the field of electromagnetic wave (EMW) absorption due to their unique physicochemical properties. However, it is still a considerable challenge ...Organic–inorganic hybrid perovskites are quite promising candidates in the field of electromagnetic wave (EMW) absorption due to their unique physicochemical properties. However, it is still a considerable challenge to satisfy the light weight, broad bandwidth, and strong absorption properties simultaneously. Herein, the solution of methylammonium lead iodide (MAPbI3) perovskites was infiltrated into the pores of reduced graphene oxide (rGO) aerogels. After drying, a series of MAPbI3/rGO composite aerogel (MGA) materials were synthesized by anchoring the MAPbI3 perovskite nanoparticles to rGO sheets with the assistance of rGO templates. Through the adjustment of component ratios, excellent EMW absorption properties are obtained with the synergistic effects of polarization loss, conduction loss, and multiple reflection and scattering of MAPbI3 and rGO. The porous structure of the aerogel and the suitable group distribution ratio allowed the MGA-4 samples to obtain excellent impedance matching and ultra-low density of ∼ 7.69 mg·cm−3. At a low filling ratio of 15 wt.%, the MGA-4 sample simultaneously achieves highly efficient and broadband EMW absorption performance at a thin thickness. The MGA-4 sample obtained a minimum reflection loss value of −64.35 dB and the effective absorption bandwidth (EAB) value of 5.4 GHz at a thickness of 2.08 mm and a maximum EAB (EABmax) value of 6.2 GHz under 2.22 mm. The MGA-5 sample obtained a maximum EAB value of 6.4 GHz with the thinckness of 2.16 mm. Furthermore, the simulation results of the radar cross-section (RCS) verified the component-optimized composites are capable of achieving excellent EMW attenuation. This paper provides a new approach and valuable reference for the development of hybrid perovskite-based microwave absorption materials with lightweight, ultra-broadband, and strong absorption properties.展开更多
Driven by their many unique features,perovskite solar cells(PSCs)have become one of the most promising candidates in the photovoltaic field.Two-step preparation of perovskite film is advantageous for its higher stabil...Driven by their many unique features,perovskite solar cells(PSCs)have become one of the most promising candidates in the photovoltaic field.Two-step preparation of perovskite film is advantageous for its higher stability and reproducibility compared to the one-step method,which is more suitable for practical application.However,the incomplete conversion of the dense lead iodide(PbI_(2))layer during the sequential spin-coating of formamidinium/methylammonium(FA^(+)/MA^(+))organic amine salts severely affect the performance of PSCs.Herein,sodium bicarbonate(NaHCO_(3))is used to induce the formation of porous PbI_(2),which facilitates the penetration of the FA^(+)/MA^(+)ions and the formation of a perovskite film with high crystallinity and large grain microstructure.Meanwhile,the introduction of Na^(+)not only improves the energetic alignment of the PSC,but also increases the conductivity via p-doping.As a result,the optimized NaHCO_(3)-modified PSC achieves a champion power conversion efficiency of 24.0% with suppressed hysteresis.Moreover,the significant reduction in defect density and ion migration as well as a mild alkaline environment enhance the stability of device.The unencapsulated NaHCO_(3)-modified PSCs maintain over 90% of their original efficiency upon storage in ambient air(30%–40% relative humidity)for 2160 h.We have demonstrated an ingenious strategy for controlling the quality of perovskite and improving the performance of device by low-temperature foaming of simple inorganic molecules of NaHCO_(3).展开更多
The coordination polymer [（DBU-H）（PbI3）]n（DBU=catena-（1,8-diazabicyclo[5,4,0]-undec-7-ene） was synthesized by self-assembly reaction of DBU and PbI2 at room temperature with pH=6.0 and structurally characterize...The coordination polymer [（DBU-H）（PbI3）]n（DBU=catena-（1,8-diazabicyclo[5,4,0]-undec-7-ene） was synthesized by self-assembly reaction of DBU and PbI2 at room temperature with pH=6.0 and structurally characterized by means of X-ray single crystal diffraction. It crystallizes in monoclinic system with space group P21/c and crystal parameters a = 1.1940（2） nm, b = 1.7409（4） nm, c = 0.81347（16） nm, β= 100.32（3）°, chemical formula C9H17N213Pb and Mr=741.15, V= 1.6635（6） nm^3, Z=4, Dc=2.959 g/cm^3, F（000）= 1304,μ（Mo Kα）= 15.687 mm^-1, the final R=0.0389 and wR=0.0635 for 2279 observed reflections with 1〉2σ（I）. Structure analysis shows that the inorganic anion chain consists of distorted PbI6 octahedra, which shares the same faces with adjacent PbI6 units to form one-dimensional infinite chains along the c-axis. Anion chains are surrounded by protonated （DBU-H）^＋ cations. Anion chains and cations are in combination with each other by static attracting forces in the crystal to form so-called organic-inorganic hybrid structure. According to the crystal structure data, quantum chemical calculation with DFT at B3LYP level was used to reveal the electronic structure of title compound.展开更多
基金financially supported by the National Natural Science Foundation of China(U21A2078,22179042,and 12104170)the Natural Science Foundation of Fujian Province(2020J06021 and 2020J01064)Scientific Research Funds of Huaqiao University(23BS109)。
文摘Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.
基金Supported by the National Natural Science Foundation of China(Nos.51521001,51832003)。
文摘A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions.Synthetic PbI_(2)was successfully applied for preparation of perovskite precursors to fabricate solar cells.This regulation of ChiSifiCa on PbI_(2)improves the power conversion efficiency of corresponding perovskite solar cells to 16%.The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.
基金Project supported by the Key Research and Development Program of China(Grant No.2020YFB1506400)the National Natural Science Foundation of China(Grant Nos.51922074,51673138,51820105003,and 22075194)+1 种基金the Tang Scholar,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Collaborative Innovation Center of Suzhou Nano Science and Technology.
文摘Formamidinium lead triiodide(FAPbI_(3))is a research hotspot in perovskite photovoltaics due to its broad light absorption and proper thermal stability.However,quite a few researches focused on the stability of the FAPbI_(3) perovskite precursor solutions.Besides,the most efficient FAPbI_(3) layers are prepared by the spin-coating method,which is limited to the size of the device.Herein,the stability of FAPbI_(3) perovskite solution with methylammonium chloride(MACl)or cesium chloride(CsCl)additive is studied for preparing perovskite film through an upscalable blade-coating method.Each additive works well for achieving a high-quality FAPbI_(3) film,resulting in efficient carbon electrode perovskite solar cells(pero-SCs)in the ambient condition.However,the perovskite solution with MACl additive shows poor aging stability that noα-FAPbI_(3) phase is observed when the solution is aged over one week.While the perovskite solution with CsCl additive shows promising aging stability that it still forms high-quality pureα-FAPbI_(3) perovskite film even the solution is aged over one month.During the solution aging process,the MACl could be decomposed into methylamine which will form some unfavored intermediated phase inducingδ-phase FAPbI_(3).Whereas,replacing MACl with CsCl could effectively solve this issue.Our founding shows that there is a great need to develop a non-MACl FAPbI_(3) perovskite precursor solution for cost-effective preparation of pero-SCs.
基金The work in Groningen was partially supported by the European Research Council,ERC Starting Grant(No.306983)‘Hybrid solution processable materials for opto-electronic devices’(ERC-HySPOD)by the Foundation for Fundamental Research on Matter(FOM)which is part of the Netherlands Organization for Scientific Research(NWO),under the framework of the FOM Focus Group‘Next Generation Organic Photovoltaics’.J Even’s work is supported by the Fondation d’entreprises banque Populaire de l’Ouest under Grant PEROPHOT 2015.The technical support of A Kamp and J Kuiper is highly appreciated.We thank TTM Palstra for insightful discussions.
文摘Formamidinium lead iodide(FAPbI3)is a newly developed hybrid perovskite that potentially can be used in high-efficiency solution-processed solar cells.Here,the temperature-dependent dynamic optical properties of three types of FAPbI3 perovskite films(fabricated using three different precursor systems)are comparatively studied.The time-resolved photoluminescence(PL)spectra reveal that FAPbI3 films made from the new precursor(a mixture of formamidinium iodide and hydrogen lead triiodide)exhibit the longest lifetime of 439 ns at room temperature,suggesting a lower number of defects and lower non-radiative recombination losses compared with FAPbI3 obtained from the other two precursors.From the temperature-dependent PL spectra,a phase transition in the films is clearly observed.Meanwhile,exciton-binding energies of 8.1 and 18 meV for the high-and lowtemperature phases are extracted,respectively.Importantly,the PL spectra for all of the samples show a single peak at room temperature,whereas at liquid-helium temperature the emission features two peaks:one in higher energy displaying a fast decay(0.5 ns)and a second red-shifted peak with a decay of up to several microseconds.These two emissions,separated by~18 meV,are attributed to free excitons and bound excitons with singlet and triplet characters,respectively.
基金Project supported by the Fundamental Research Funds for the Central South University,China(Grant No.2019zzts426)the National Natural Science Foundation of China(Grant Nos.61172047,61774170,and 51673218)+1 种基金the Scientific and Technological Project of Hunan Provincial Development and Reform Commission,China,the National Science Foundation,USA(Grant Nos.CBET-1437656 and DMR-1903962)the Innovation-Driven Project of Central South University(Grant No.2020CX006)。
文摘SiO2 nanoparticles were used to regulate the crystallizing process of lead halide perovskite films prepared by the sequential deposition method,which was used in the low-temperature-processed,carbon-electrode-basing,hole-conductor-free planar perovskite solar cells.It was observed that,after adding small amount of SiO2 precursor(1 vol%)into the lead iodide solution,performance parameters of open-circuit voltage,short-circuit current and fill factor were all upgraded,which helped to increase the power conversion efficiency(reverse scan)from 11.44(±1.83)%(optimized at 12.42%)to 14.01(±2.14)%(optimized at 15.28%,AM 1.5G,100 mW/cm^2).Transient photocurrent decay curve measurements showed that,after the incorporation of SiO2 nanoparticles,charge extraction was accelerated,while transient photovoltage decay and dark current curve tests both showed that recombination was retarded.The improvement is due to the improved crystallinity of the perovskite film.X-ray diffraction and scanning electron microscopy studies observed that,with incorporation of amorphous SiO2 nanoparticles,smaller crystallites were obtained in lead iodide films,while larger crystallites were achieved in the final perovskite film.This study implies that amorphous SiO2 nanoparticles could regulate the coarsening process of the perovskite film,which provides an effective method in obtaining high quality perovskite film.
基金financial support from the Development and Promotion of Science and Technology Talent Project(DPST) and Graduate School,Chiang Mai University
文摘Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) solar cell devices was performed by using iso-butyl ammonium iodide(IBA)passivated on Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) films.The n-i-p structure of perovskite solar cell devices was fabricated with the structure of FTO/SnO_(2)/Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3)(FTO,i.e.,fluorine doped tin oxide)and IBA/Spiro-OMeTAD/Ag.The effect of different weights of IBA passivated on Cs-doped perovskite solar cells(PSCs)was systematically investigated and compared with non-passivated devices.It was found that the 5-mg IBA-passivated devices exhibited a high power conversion efficiency(PCE)of 15.49%higher than 12.64%of non-IBA-passivated devices.The improvement of photovoltaic parameters of the 5-mg IBA-passivated device can be clearly observed compared to the Cs-doped device.The better performance of the IBA-passivated device can be confirmed by the reduction of PbI_(2) phase in the crystal structure,lower charge recombination rate,lower charge transfer resistance,and improved contact angle of perovskite films.Therefore,IBA passivation on Cs_(0.1)(CH_(3)NH)_(0.9)PbI_(3) is a promising technique to improve the efficiency of Cs-doped perovskite solar cells.
基金funded partly by the National Natural Science Foundation of China(Grant No.51950410581)the Shanghai Pujiang Program+2 种基金the Open Fund of Zhejiang Tsinghua Institute of Flexible Electronics Technologyfunding from the National Natural Science Foundation of China(Grant No.21604053)funding from the ECNU Multifunctional Platform for Innovation(003,006).
文摘Previous reports of formamidinium/methylamine(FAMA)-mixed halide perovskite solar cells have focused mainly on controlling the morphology of the perovskite film and its interface—for example,through the inclusion of bromine and surface passivation.In this paper,we describe a new processing pathway for the growth of a high-quality bromine-free FAMAPbI3 halide perovskites via the control of intermediate phase.Through low-temperature aging growth(LTAG)of a freshly deposited perovskite film,α-phase perovskites can be seeded in the intermediate phase and,at the same time,prevent beta-phase perovskite to nucleate.After postannealing,large grain-size perovskites with significantly reduced PbI2 presence on the surface can be obtained,thereby eliminating the need of additional surface passivation step.Our pristine LTAG-treated solar cells could provide PCEs of greater than 22%without elaborate use of bromine or an additional passivation layer.More importantly,when using this LTAG process,the growth of the pure alpha-phase FAMAPbI3 was highly reproducible.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11974257)the Distinguished Young Talent Funding of Jiangsu Province, China (Grant No. BK20200003)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation functionals,such as local density approximation,grand gradient approximation(GGA),and hybrid functionals,either underestimate band gaps or misplace defect levels.In this study,we revisited iodine defects in CH_(3)NH_(3)PbI_(3) by combining the accuracy of total energy calculations of GGA and single-electron level calculation of the GW method.The combined approach predicted neutral Im_(i) to be unstable and the transition level of Im_(i)(+1/-1)to be close to the valence band maximum.Therefore,Im_(i) may not be as detrimental as previously reported.Moreover,Vm I may be unstable in the-1 charged state but could still be detrimental owing to the deep transition level of Vm I(+1/0).These results could facilitate the further understanding of the intrinsic point defect and defect passivation observed in CH_(3)NH_(3)PbI_(3).
基金the Special Foundation for Young Scientists of Fuzhou University (XRC-0644)Sci & Tech Promotion Foundation of Fuzhou University (XJJ-0605)Foundation of Education Committee of Fujian Province (JB06013)
文摘A new lead（Ⅱ） iodide coordination polymer [（npq）（PbI3）]n1 （npq = N-propyl- quinolinium） has been synthesized in the presence of npq as structure-directing reagent （SDA）. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 19.158（4）, b = 7.9909（16）, c = 22.929（5） A, V = 3510.2（12） A3, Z = 8, Dc = 2.877 g/cm3, F（000） = 2672, C12H1413NPb, Mr= 760.14, μ（MoKα） = 14.872 mm-1, the final R = 0.0431 and wR = 0.1021 for 3678 observed reflections with Ⅰ 〉 2σ（Ⅰ）. Structure determination indicates that the [PbI3]^-n infinite chains in each unit cell shape the sketch of 1, which could be described as the result of face-sharing distorted PbI6 octahedra running along the b axis. Electrostatic interaction between conjugated organic counter-cations and inorganic moieties presents and contributes to the crystal packing. 1 was further characterized with IR and elemental analysis. Based on the crystal structure data, quantum chemical calculation with DFT method was used to reveal the electronic structure and optical property of 1.
基金National Natural Science Foundation of China(no.21801104)and Fundamental Research Funds for the Central Universities(no.lzujbky-2019-sp01).Y.-Y.W.acknowledges funding support from the U.S.Department of Energy(award no.DEFG02-07ER46427).The authors sincerely thank the theoretical calculation support of Prof.Penji Yan from Hexi University of China.
文摘The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.
基金supported by the Natural Science Foundation of Fujian Province (E0710008 and X0650070)the Innovation Fund for Young Scientist of Fujian Province (2007F3049)
文摘A new iodiplumbate polymer [（AOD）（Pb216）]n 1 （AOD = O-protonated 4-azonia-7- oxaspiro（4,5） decane quaternary ammonium） was synthesized by self-assembly reaction of AOD-I, Pb（NO3）2 and NaI, and structurally determined. Compound 1 crystallizes in the hexagonal system, space group P3, with a = 18.2704（8）, c = 8.1663（6） A, V= 2360.8（2） A3, Z = 3, De = 2.783 g/cm^3, F（000） = 1686, C8H17I6NOPb2, Mr = 1319.03, μ（MoKa） = 16.562 mm^-1, the final R = 0.0535 and wR = 0.1793 for 4943 observed reflections with I 〉 2σ（I）. In compound 1, three independent （PbEI6）^2-n infinite chains in each unit cell shape the sketch of compound 1 under the template of AOD-H^2＋ cation. Each （PbaI6）^2-n chain generates from the face-sharing of distorted PbI6 octahedra. （PbEI6）^2-n polyanions interact with AOD-H^2＋ cations by electrostatic interaction in the crystal to feature a so-called hybrid structure. Compound 1 was further characterized with IR, elemental analysis, fluorescence spectrum and thermal analysis. Based on the crystal structure data, DFT calculation was carried out to reveal the electronic structure of compound 1.
基金financial support from the National Natural Science Foundation of China(No.52103223)the Natural Science Basic Research Program of Shaanxi(No.2023-JC-YB-413)+2 种基金the Natural Science Foundation of Heilongjiang Province of China(No.YQ2023E027)the Key Laboratory of Functional Molecular Solids,Ministry of Education(No.FMS20230010)the Fundamental Research Funds for the Central Universities(Nos.3072024GH2605,3072024XX2613,and 3072024XX2616).
文摘Organic–inorganic hybrid perovskites are quite promising candidates in the field of electromagnetic wave (EMW) absorption due to their unique physicochemical properties. However, it is still a considerable challenge to satisfy the light weight, broad bandwidth, and strong absorption properties simultaneously. Herein, the solution of methylammonium lead iodide (MAPbI3) perovskites was infiltrated into the pores of reduced graphene oxide (rGO) aerogels. After drying, a series of MAPbI3/rGO composite aerogel (MGA) materials were synthesized by anchoring the MAPbI3 perovskite nanoparticles to rGO sheets with the assistance of rGO templates. Through the adjustment of component ratios, excellent EMW absorption properties are obtained with the synergistic effects of polarization loss, conduction loss, and multiple reflection and scattering of MAPbI3 and rGO. The porous structure of the aerogel and the suitable group distribution ratio allowed the MGA-4 samples to obtain excellent impedance matching and ultra-low density of ∼ 7.69 mg·cm−3. At a low filling ratio of 15 wt.%, the MGA-4 sample simultaneously achieves highly efficient and broadband EMW absorption performance at a thin thickness. The MGA-4 sample obtained a minimum reflection loss value of −64.35 dB and the effective absorption bandwidth (EAB) value of 5.4 GHz at a thickness of 2.08 mm and a maximum EAB (EABmax) value of 6.2 GHz under 2.22 mm. The MGA-5 sample obtained a maximum EAB value of 6.4 GHz with the thinckness of 2.16 mm. Furthermore, the simulation results of the radar cross-section (RCS) verified the component-optimized composites are capable of achieving excellent EMW attenuation. This paper provides a new approach and valuable reference for the development of hybrid perovskite-based microwave absorption materials with lightweight, ultra-broadband, and strong absorption properties.
基金The authors acknowledge the joint financial support from the National Natural Science Foundation of China(Nos.51972123,U1705256,22271106,and U20A20150)。
文摘Driven by their many unique features,perovskite solar cells(PSCs)have become one of the most promising candidates in the photovoltaic field.Two-step preparation of perovskite film is advantageous for its higher stability and reproducibility compared to the one-step method,which is more suitable for practical application.However,the incomplete conversion of the dense lead iodide(PbI_(2))layer during the sequential spin-coating of formamidinium/methylammonium(FA^(+)/MA^(+))organic amine salts severely affect the performance of PSCs.Herein,sodium bicarbonate(NaHCO_(3))is used to induce the formation of porous PbI_(2),which facilitates the penetration of the FA^(+)/MA^(+)ions and the formation of a perovskite film with high crystallinity and large grain microstructure.Meanwhile,the introduction of Na^(+)not only improves the energetic alignment of the PSC,but also increases the conductivity via p-doping.As a result,the optimized NaHCO_(3)-modified PSC achieves a champion power conversion efficiency of 24.0% with suppressed hysteresis.Moreover,the significant reduction in defect density and ion migration as well as a mild alkaline environment enhance the stability of device.The unencapsulated NaHCO_(3)-modified PSCs maintain over 90% of their original efficiency upon storage in ambient air(30%–40% relative humidity)for 2160 h.We have demonstrated an ingenious strategy for controlling the quality of perovskite and improving the performance of device by low-temperature foaming of simple inorganic molecules of NaHCO_(3).
文摘The coordination polymer [（DBU-H）（PbI3）]n（DBU=catena-（1,8-diazabicyclo[5,4,0]-undec-7-ene） was synthesized by self-assembly reaction of DBU and PbI2 at room temperature with pH=6.0 and structurally characterized by means of X-ray single crystal diffraction. It crystallizes in monoclinic system with space group P21/c and crystal parameters a = 1.1940（2） nm, b = 1.7409（4） nm, c = 0.81347（16） nm, β= 100.32（3）°, chemical formula C9H17N213Pb and Mr=741.15, V= 1.6635（6） nm^3, Z=4, Dc=2.959 g/cm^3, F（000）= 1304,μ（Mo Kα）= 15.687 mm^-1, the final R=0.0389 and wR=0.0635 for 2279 observed reflections with 1〉2σ（I）. Structure analysis shows that the inorganic anion chain consists of distorted PbI6 octahedra, which shares the same faces with adjacent PbI6 units to form one-dimensional infinite chains along the c-axis. Anion chains are surrounded by protonated （DBU-H）^＋ cations. Anion chains and cations are in combination with each other by static attracting forces in the crystal to form so-called organic-inorganic hybrid structure. According to the crystal structure data, quantum chemical calculation with DFT at B3LYP level was used to reveal the electronic structure of title compound.
