摘要
甲脒(FA)基钙钛矿比甲胺(MA)基钙钛矿具有更高的内在稳定性,而无机Cs离子掺杂可以进一步提高钙钛矿的湿度、热和结构稳定性。通过一步反溶剂法制备了Cs掺杂的FA_(1-x)Cs_(x)Pb Br_(3)(x=0,0.05,0.10,0.15)钙钛矿薄膜,采用椭圆偏振光谱研究了材料的复介电函数并以此进行外量子效率(EQE)模拟。EQE模拟结果显示掺杂比例为0.05时,钙钛矿薄膜具有最高的功率转换效率(PCE),可达23.47%。进一步对FA_(0.95)Cs_(0.05)Pb Br_(3)进行变温椭偏分析,发现:随着温度升高,材料带隙增大,在393 K左右,从变温复介电函数的二阶导谱中可观察到相变现象,钙钛矿材料由正交相转变为四方相。对基于FA_(0.95)Cs_(0.05)Pb Br_(3)的太阳能电池进行变温EQE模拟,结果表明:温度对器件的最高PCE影响不大,其效率可以稳定在23.47%左右,但是高温会导致器件近红外区的外量子效率降低,器件的整体响应带宽减小。
Objective Perovskite solar cells(PSCs)have attracted considerable research interest due to their large absorption coefficients,long diffusion lengths,tunable bandgap,and high charge mobility.The power conversion efficiency(PCE)of PSCs has increased from 3.8%in 2009 to 26.08%in 2023.However,their mass-scale production is limited by the inherent instability of the perovskites,which decompose easily during reaction with moisture,oxygen,light and heat.Formamidinium-cesium(FAC)mixed cations perovskites have demonstrated excellent thermal stability and suitable bandgap for solar spectrum absorption.On the other hand,the carrier mobility of Br-is higher than that of I-.Therefore,we choose Cs-doped FA_(1-x)Cs_(x)PbBr_(3)(FACsPbBr_(3))thin films to study optical properties and construct high-efficient and stable PSCs.However,experimental PCE verification of PSCs is costly and time-consuming.Numerical simulation provides a simple and effective way to evaluate the PSCs performance and explore new possible device architectures.The complex dielectric function is an important optical parameter.Fundamentally,the complex dielectric functions are critical for simulating the external quantum efficiency(EQE)of the PSCs.Furthermore,determining the bandgap from the complex dielectric functions provides information on the band structure and enables the detection of temperature-dependent phase changes.We prepare Cs-doped FA_(1-x)Cs_(x)PbBr_(3)(x=0,0.05,0.10,0.15)perovskite thin films and study the corresponding complex dielectric functions by spectroscopic ellipsometry(SE).The resultant complex dielectric functions are then employed to simulate EQE.Meanwhile,the temperature-dependent EQE simulation of FA_(0.95)Cs_(0.05)PbBr_(3) PSC is also performed.We hope that the basic findings can help design highly efficient and stable PSCs and understand the relationship between the complex dielectric functions and EQE of PSCs.Methods FACsPbBr_(3) thin films with different Cs doping concentrations are prepared by one-step anti-solvent method,and
作者
李杨
吕泽元
苟婷
赵明琳
戴俊
Li Yang;LüZeyuan;Gou Ting;Zhao Minglin;Dai Jun(School of Science,Jiangsu University of Science and Technology,Zhenjiang 212000,Jiangsu,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2023年第23期326-332,共7页
Acta Optica Sinica
基金
国家自然科学基金(11874185)
江苏省研究生科研创新计划(KYCX23_3822)。
关键词
薄膜
Cs掺杂钙钛矿
光学性质
变温椭圆偏振光谱
外量子效率模拟
thin films
Cs-doped perovskite
optical properties
temperature-dependent ellipsometry spectrum
external quantum efficiency simulation
