Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation en...Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)films.Such a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)phase.Theoretical calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)planes.Therefore,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation stability.Meanwhile,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.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
Two-dimensional(2D)precursor molecules-based surface treatment on three-dimensional(3D)lead halide perovskite(PVSK)has achieved huge successes,the in-depth understanding of the modification mechanism remains an urgent...Two-dimensional(2D)precursor molecules-based surface treatment on three-dimensional(3D)lead halide perovskite(PVSK)has achieved huge successes,the in-depth understanding of the modification mechanism remains an urgent need.Here the effect of alkyl-chain length on the reaction dynamics between alkylammonium salts(XI)and 3D PVSK matrix is studied,through examination of surface morphological and crystallographic properties of the 3D PVSK matrix.It is observed that the average crystallite size of 3D PVSK increases as XI is either spin-coated on 3D PVSK or penetrated through carbon-electrode(during the“in-situ healing”process).Secondary growth is observed for 3D PVSK,which is related to ion-exchanging reactions.Prolonging alkyl-chain length favors the secondary growth.Besides,the formation dynamics of 2D PVSK are studied.Adding alkyl-chain length increases the yields.The observations are thoroughly discussed with respect to the steric-hindrance effect held by alky-chains of XI molecule.The improved crystallization of 3D PVSK and increased yields of 2D PVSK help accelerate charge extraction and reduce recombination across the interface between PVSK and carbon-electrode(CE).Tuning alkyl-chain length of XI molecules,and the mass ratio between XI molecules and carbon black could mitigate the“in-situ healing”effect.Power conversion efficiency(PCE)of the carbonelectrode-based hole-conductor-free planar perovskite solar cells has been upgraded from 14% to 17%,and further upgraded to 20.4% by utilizing relatively thick CEs.Thanks to the hydrophobicity of long alkyl-chains owned by XI molecules,prolonged stability has been achieved on unsealed devices at the high-moisture environment(RH≈85%),meanwhile,shelf-stability up to 6400 h has been achieved.This study deepens the understanding of the 2D precursor-basing modification strategies.展开更多
基金the financial support from the National Key R&D program of China(2021YFF0500501 and 2021YFF0500504)the Fundamental Research Funds for the Central Universities(YJS2213 and JB211408)+1 种基金the National Natural Science Foundation of China(61874083)the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-014)
文摘Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)films.Such a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)phase.Theoretical calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)planes.Therefore,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation stability.Meanwhile,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.
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 of the National Natural Science Foundation of China(NSFC,No.62374185)the Key Scientific Research Project of Education Department of Hunan Province(No.22A0005)the financial support from the Fundamental Research Funds for the Central South University(No.2024ZZTS0478)。
文摘Two-dimensional(2D)precursor molecules-based surface treatment on three-dimensional(3D)lead halide perovskite(PVSK)has achieved huge successes,the in-depth understanding of the modification mechanism remains an urgent need.Here the effect of alkyl-chain length on the reaction dynamics between alkylammonium salts(XI)and 3D PVSK matrix is studied,through examination of surface morphological and crystallographic properties of the 3D PVSK matrix.It is observed that the average crystallite size of 3D PVSK increases as XI is either spin-coated on 3D PVSK or penetrated through carbon-electrode(during the“in-situ healing”process).Secondary growth is observed for 3D PVSK,which is related to ion-exchanging reactions.Prolonging alkyl-chain length favors the secondary growth.Besides,the formation dynamics of 2D PVSK are studied.Adding alkyl-chain length increases the yields.The observations are thoroughly discussed with respect to the steric-hindrance effect held by alky-chains of XI molecule.The improved crystallization of 3D PVSK and increased yields of 2D PVSK help accelerate charge extraction and reduce recombination across the interface between PVSK and carbon-electrode(CE).Tuning alkyl-chain length of XI molecules,and the mass ratio between XI molecules and carbon black could mitigate the“in-situ healing”effect.Power conversion efficiency(PCE)of the carbonelectrode-based hole-conductor-free planar perovskite solar cells has been upgraded from 14% to 17%,and further upgraded to 20.4% by utilizing relatively thick CEs.Thanks to the hydrophobicity of long alkyl-chains owned by XI molecules,prolonged stability has been achieved on unsealed devices at the high-moisture environment(RH≈85%),meanwhile,shelf-stability up to 6400 h has been achieved.This study deepens the understanding of the 2D precursor-basing modification strategies.
