Using time-dependent terahertz spectroscopy, we investigate the role of mixed-cation and mixed-halide on the ultrafast photoconductivity dynamics of two different methylammonium(MA) lead-iodide perovskite thin films. ...Using time-dependent terahertz spectroscopy, we investigate the role of mixed-cation and mixed-halide on the ultrafast photoconductivity dynamics of two different methylammonium(MA) lead-iodide perovskite thin films. It is found that the dynamics of conductivity after photoexcitation reveals significant correlation on the microscopy crystalline features of the samples. Our results show that mixed-cation and lead mixed-halide affect the charge carrier dynamics of the lead-iodide perovskites. In the(5-AVA)_(0.05)(MA)_(0.95) PbI_(2.95) Cl_(0.05)/spiro thin film, we observe a much weaker saturation trend of the initial photoconductivity with high excitation fluence, which is attributed to the combined effect of sequential charge carrier generation, transfer, cooling and polaron formation.展开更多
Organic-inorganic hybrid perovskites(OIHPs)offer precise control over material properties through the substitution of organic cations and halogens.In this study,two OIHPs,[(C_(6)H_(10)P)(n-BA)]Sb_(2)X_(9)([C_(6)H_(10)...Organic-inorganic hybrid perovskites(OIHPs)offer precise control over material properties through the substitution of organic cations and halogens.In this study,two OIHPs,[(C_(6)H_(10)P)(n-BA)]Sb_(2)X_(9)([C_(6)H_(10)P]^(+)=[Me_(3)PCH_(2)CH_(2)CH_(3)]+,[n-BA]+=n-butylamine cation,X=I(1),Br(2)),were synthesized by varying halogens within a mixed-cation system.The halogen substitution induced a shift from compound 1,which remains stable without phase transitions,to compound 2,which undergoes a ferroelastic phase transition(mmmF2/m).Compound 1 crystallizes in the non-centrosymmetric Pca2_(1) space group and demonstrates a second harmonic generation(SHG)response,while compound 2 displays elasticity in nanoindentation tests.Halogen substitution alters Sb—X bond lengths,inducing structural distortions in the inorganic framework and influencing the spatial configuration of organic cations and inorganic anions.These changes lead to distinct crystallization behaviors,resulting in different physical properties for compounds 1 and 2.This work contributes to the development of multifunctional materials based on halogen regulation in mixed-cation OIHPs.展开更多
The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency ...The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.展开更多
As perovskite solar cells show tremendous potential for widespread applications, we find that adding inorganic thermal-stable cesium ions into MAPbI_3 results in significantly improves thermal stability. For un-encaps...As perovskite solar cells show tremendous potential for widespread applications, we find that adding inorganic thermal-stable cesium ions into MAPbI_3 results in significantly improves thermal stability. For un-encapsulated perovskite devices, the energy conversion efficiency maintains about 75% of its original value（over 15%） in the MA_（0.85）Cs_（0.05）PbI_3 device under 80 min of heating at 140°C in a dry atmosphere（RH ≤ 30%）. With significantly improved thermal stability achieved by a convenient process, it is expected that this type of mixed-cation perovskites can further facilitate large scale applications.展开更多
FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method...FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method for surface passivation of FA-Cs perovskite layer in devices.However,it is still controversial whether the PEAI post-treatment would form two-dimensional(2D)perovskite PEA_(2)PbI_(4) capping layer or just result in PEA+terminated surface.Here in this work,the function of PEAI post-treatment on FA-Cs mixed-cation perovskite FA_(1-x)Cs_(x)PbI_(3)(x=0.1–0.9)with varied Cs contents is elucidated.With increased Cs content,the FA-Cs perovskite shows higher resistance to the cation exchange between FA+and PEA+.This Cs-content-dependent cation exchange results in the different PEAI reaction preferences with FA-Cs mixed-cation perovskites.Furthermore,higher Cs content with stronger resistance to cation exchange reaction leads to a wider processing window for post-treatment and defect passivation,which is beneficial for the fabrication of large-scale photovoltaic devices.展开更多
Chiral zero-dimensional(0D)hybrid metal halides,merging chirality with exceptional emission properties,are highly promising for circularly polarized luminescence(CPL).For CPL applications,it is difficult to simultaneo...Chiral zero-dimensional(0D)hybrid metal halides,merging chirality with exceptional emission properties,are highly promising for circularly polarized luminescence(CPL).For CPL applications,it is difficult to simultaneously achieve large dissymmetry factor(g_(lum))and photoluminescence quantum yield(PLQY).Herein,we propose a chemical design strategy to systematically control the g_(lum) and PLQY.We take achiral or chiral organic cations,to partially substitute the original A-site in A_(3)SbCl_(6)(A=(R/S)-morpholin-2-ylmethanol,R/S-MOR),to form ordered chiral-achiral halides(A)_(2)(B)SbCl_(6)(B=ethylammonium,isopropylammonium,2-chloroethylammonium,n-propylammonium,n-butylammonium),and ordered mixed chiral-chiral halides(A)_(2)(C)SbCl_(6)(C=(R/S)-1-amino-2-propanol),respectively.The introduction of different natures of cations not only systematically alters the PLQY(up to 86.0%)by increasing the Sb···Sb distances and[SbCl_(6)]^(3-)octahedral distortion,but also significantly amplifies the chirality with enhanced g_(lum).Among them,the mixed chiral-chiral material achieves the largest g_(lum) value(~9×10^(-3))with a high PLQY of 71.6%.The added dimension of a different chiral source reinforces the chirality and suppresses the inorganic octahedra vibration via hydrogen bonding interactions between the hydroxyl group and[SbCl_(6)]^(3-)octahedra.This work showcases an effective strategy to enhance the chiroptic properties and unlocks a large variety of new functional hybrid halides with ordered chiral/achiral cation combinations.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11604202,11674213,61735010 and 51603119the Young Eastern Scholar under Grant Nos QD2015020 and QD2016027+3 种基金the Shanghai Rising-Star Program under Grant No18QA1401700the ‘Chen Guang’ Project under Grant Nos 16CG45 and 16CG46the Shanghai Municipal Education Commissionthe Shanghai Education Development Foundation
文摘Using time-dependent terahertz spectroscopy, we investigate the role of mixed-cation and mixed-halide on the ultrafast photoconductivity dynamics of two different methylammonium(MA) lead-iodide perovskite thin films. It is found that the dynamics of conductivity after photoexcitation reveals significant correlation on the microscopy crystalline features of the samples. Our results show that mixed-cation and lead mixed-halide affect the charge carrier dynamics of the lead-iodide perovskites. In the(5-AVA)_(0.05)(MA)_(0.95) PbI_(2.95) Cl_(0.05)/spiro thin film, we observe a much weaker saturation trend of the initial photoconductivity with high excitation fluence, which is attributed to the combined effect of sequential charge carrier generation, transfer, cooling and polaron formation.
基金supported by the National Natural Science Foundation of China(22275033)the Natural Science Foundation of Jiangsu Province(JSNSF)(BK20230810).
文摘Organic-inorganic hybrid perovskites(OIHPs)offer precise control over material properties through the substitution of organic cations and halogens.In this study,two OIHPs,[(C_(6)H_(10)P)(n-BA)]Sb_(2)X_(9)([C_(6)H_(10)P]^(+)=[Me_(3)PCH_(2)CH_(2)CH_(3)]+,[n-BA]+=n-butylamine cation,X=I(1),Br(2)),were synthesized by varying halogens within a mixed-cation system.The halogen substitution induced a shift from compound 1,which remains stable without phase transitions,to compound 2,which undergoes a ferroelastic phase transition(mmmF2/m).Compound 1 crystallizes in the non-centrosymmetric Pca2_(1) space group and demonstrates a second harmonic generation(SHG)response,while compound 2 displays elasticity in nanoindentation tests.Halogen substitution alters Sb—X bond lengths,inducing structural distortions in the inorganic framework and influencing the spatial configuration of organic cations and inorganic anions.These changes lead to distinct crystallization behaviors,resulting in different physical properties for compounds 1 and 2.This work contributes to the development of multifunctional materials based on halogen regulation in mixed-cation OIHPs.
基金supported by the National Basic Research Program of China(Grant No.2015CB932203)the National Natural Science Foundation of China(Grant Nos.61722501,and 61377025)+2 种基金the Beijing Natural Science Foundation(Grant No.4164106)the Scientific Experimental System in Near Space of Chinese Academy of Sciences(Grant No.XDA17000000)the General Financial Grant from the China Postdoctoral Science Foundation(Grant No.2017M620519)
文摘The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.
基金jointly supported by the State Key Program for Basic Research of China(No.2015CB659300)the National Natural Science Foundation of China(Nos.11621091 and 11574143)+2 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20150056)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Fundamental Research Funds for the Central Universities
文摘As perovskite solar cells show tremendous potential for widespread applications, we find that adding inorganic thermal-stable cesium ions into MAPbI_3 results in significantly improves thermal stability. For un-encapsulated perovskite devices, the energy conversion efficiency maintains about 75% of its original value（over 15%） in the MA_（0.85）Cs_（0.05）PbI_3 device under 80 min of heating at 140°C in a dry atmosphere（RH ≤ 30%）. With significantly improved thermal stability achieved by a convenient process, it is expected that this type of mixed-cation perovskites can further facilitate large scale applications.
基金supported by the National Key Research and Development Program of China(2017YFE0127100)the National Natural Science Foundation of China(NSFC,Grant 22025505)+1 种基金the Program of Shanghai Academic Technology Research Leader(Grant 20XD1422200)the Key Laboratory of Resource Chemistry,Ministry of Education(KLRC_ME2003)。
文摘FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method for surface passivation of FA-Cs perovskite layer in devices.However,it is still controversial whether the PEAI post-treatment would form two-dimensional(2D)perovskite PEA_(2)PbI_(4) capping layer or just result in PEA+terminated surface.Here in this work,the function of PEAI post-treatment on FA-Cs mixed-cation perovskite FA_(1-x)Cs_(x)PbI_(3)(x=0.1–0.9)with varied Cs contents is elucidated.With increased Cs content,the FA-Cs perovskite shows higher resistance to the cation exchange between FA+and PEA+.This Cs-content-dependent cation exchange results in the different PEAI reaction preferences with FA-Cs mixed-cation perovskites.Furthermore,higher Cs content with stronger resistance to cation exchange reaction leads to a wider processing window for post-treatment and defect passivation,which is beneficial for the fabrication of large-scale photovoltaic devices.
基金supported by the Research and Development Fund of Inner Mongolia University(21300-5187174)the Program of Higher-Level Talents of Inner Mongolia University(10000-23112101/105)the National Natural Science Foundation of China(22275077,22461160285 and 22401161).
文摘Chiral zero-dimensional(0D)hybrid metal halides,merging chirality with exceptional emission properties,are highly promising for circularly polarized luminescence(CPL).For CPL applications,it is difficult to simultaneously achieve large dissymmetry factor(g_(lum))and photoluminescence quantum yield(PLQY).Herein,we propose a chemical design strategy to systematically control the g_(lum) and PLQY.We take achiral or chiral organic cations,to partially substitute the original A-site in A_(3)SbCl_(6)(A=(R/S)-morpholin-2-ylmethanol,R/S-MOR),to form ordered chiral-achiral halides(A)_(2)(B)SbCl_(6)(B=ethylammonium,isopropylammonium,2-chloroethylammonium,n-propylammonium,n-butylammonium),and ordered mixed chiral-chiral halides(A)_(2)(C)SbCl_(6)(C=(R/S)-1-amino-2-propanol),respectively.The introduction of different natures of cations not only systematically alters the PLQY(up to 86.0%)by increasing the Sb···Sb distances and[SbCl_(6)]^(3-)octahedral distortion,but also significantly amplifies the chirality with enhanced g_(lum).Among them,the mixed chiral-chiral material achieves the largest g_(lum) value(~9×10^(-3))with a high PLQY of 71.6%.The added dimension of a different chiral source reinforces the chirality and suppresses the inorganic octahedra vibration via hydrogen bonding interactions between the hydroxyl group and[SbCl_(6)]^(3-)octahedra.This work showcases an effective strategy to enhance the chiroptic properties and unlocks a large variety of new functional hybrid halides with ordered chiral/achiral cation combinations.
