动态热风辅助再结晶策略改善CsPbI_(2)Br钙钛矿在大气环境下的结晶及其光电性能  

Improving crystallization and photoelectric performance of CsPbI_(2)Br perovskite under ambient air via dynamic hot-air assisted recrystallization strategy

作　　者：张子发 袁翔 鹿颖申 何丹敏 严全河 曹浩宇 洪峰 蒋最敏[2] 徐闰[3] 马忠权 宋宏伟 徐飞 Zhang Zi-Fa;Yuan Xiang;Lu Ying-Shen;He Dan-Min;Yan Quan-He;Cao Hao-Yu;Hong Feng;Jiang Zui-Min;Xu Run;Ma Zhong-Quan;Song Hong-Wei;Xu Fei(Shanghai Key Laboratory of High Temperature Superconductors,College of Sciences,Shanghai University,Shanghai 200444,China;State Key Laboratory of Surface Physics,Department of Physics,Fudan University,Shanghai 200433,China;Department of Electronic Information Materials,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学理学院,上海市高温超导重点实验室,上海200444 [2]复旦大学物理系,应用表面物理国家重点实验室,上海200433 [3]上海大学电子信息材料系,上海200444

出　　处：《物理学报》2024年第9期326-335,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62350054,12175131,12374379)资助的课题.

摘　　要：CsPbI_(2)Br薄膜在大气环境下制备存在覆盖率低、结晶质量差和结构稳定性差等问题.本文提出了一种动态热风辅助再结晶策略(dynamic hot-air assisted recrystallization,DHR),在相对湿度大于60%(>60%RH)的大气环境下,制备出高覆盖率、(100)择优取向、大尺寸晶粒、结构稳定、光电性能好的CsPbI_(2)Br薄膜.这是由于动态热风过程能够有效提高薄膜的覆盖率和获得(100)择优取向的结晶,但晶粒尺寸会显著减小(R_(ave)=0.32μm)并伴随着大量的晶界形成,从而加剧载流子的非辐射复合(τ_(ave)=99 ns);而通过再结晶过程,可进一步提高(100)择优取向的结晶和显著增大晶粒尺寸(R_(ave)=2.63μm),从而提高薄膜的光致发光强度和荧光寿命(τ_(ave)=118 ns).由DHR策略制备的未封装CsPbI_(2)Br太阳能电池具备高光电转换效率(power conversion efficiency,PCE=17.55%)、低迟滞因子(hysteresis index,HI=2.34%)和长期的储存稳定性(air,>60%RH,40天,初始PCE的96%)等特性.CsPbI_(2)Br thin films prepared in ambient air are susceptible to humidity,resulting in low coverage,poor crystallization quality,numerous pinholes,and easy transformation into non perovskite phases.To overcome the troubles of pervoksite fabrication in ambient air,a feasible way is to reduce the moisture around the films as much as possible according to dynamic hot-air assisted strategy.However,the hot air accelerates the evaporation rate of solvent,resulting in the decrease of grain size.In order to improve the crystal growth and long-term stability in dynamic hot-air assisted strategy,in this work,we present a dynamic hot-air assisted recrystallization(DHR)strategy to prepare high-quality CsPbI_(2)Br thin films in ambient air(i.e.the CsPbI_(2)Br thin films prepared via dynamic hot-air strategy are recrystallized by using a green solvent(methylamine acetate)with high viscosity coefficient).Under ambient air with high humidity(RH>60%),the CsPbI_(2)Br thin film with high coverage,(100)preferred orientation,large average grain size,and stable structure is prepared via DHR strategy.The dynamic hot-air process can effectively reduce the moisture around the film and increase the nucleation sites in the precursor solution,thereby improving the coverage of the film.However,this process inevitably results in the significant decrease of grain size(R_(ave)=0.32μm)(i.e.more grain boundaries),exacerbating non-radiative recombination of carriers associated with trap states at these boundaries.The high coverage increases the grain-to-grain contact area,facilitating complete recrystallization.Thus,the recrystallization process can significantly increase the grain size(R_(ave)=2.63μm)and obtain a(100)preferred orientation(I(110)/I(200)=0.006),resulting in high photoluminescence intensity and long fluorescence lifetime(118 ns).The unencapsulated CsPbI_(2)Br perovskite solar cell(PSC)optimized via DHR strategy with low hysterescence factor(2.34%)and high repeatability exhibits a high power conversion efficiency(PCE=17.55%),which

关 键 词：CsPbI_(2)Br 动态热风辅助再结晶 大气环境 光电性能 

分 类 号：TM914.4[电气工程—电力电子与电力传动]