双配体策略制备大气环境下性能稳定的CsPbIBr_(2)光电探测器  

Air-stable CsPbIBr_(2) photodetector via dual-ligand-assisted solution strategy

作　　者：胡紫婷 舒鑫 王香 李跃[1] 徐闰[2] 洪峰[1] 马忠权[1] 蒋最敏[3] 徐飞[1,3] Hu Zi-Ting;Shu Xin;Wang Xiang;Li Yue;Xu Run;Hong Feng;Ma Zhong-Quan;Jiang Zui-Min;Xu Fei(SHU-SolarE R&D Lab,Shanghai Key Laboratory of High Temperature Superconductors,Department of Physics,Shanghai University,Shanghai 200444,China;Department of Electronic Information Materials,Shanghai University,Shanghai 200444,China;State Key Laboratory of Surface Physics,Ministry of Education Key Laboratory of Micro-Nano Photonic Structure,Department of Physics,Fudan University,Shanghai 200433,China)

机构地区：[1]上海大学物理系,上海大学-索朗光伏材料与器件R&D联合实验室,上海市高温超导重点实验室,上海200444 [2]上海大学电子信息材料系,上海200444 [3]复旦大学物理系,应用表面物理国家重点实验室,微纳光子结构教育部重点实验室,上海200433

出　　处：《物理学报》2022年第11期305-313,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12175131,61874070);上海市自然科学基金(批准号:17ZR1409600)资助的课题。

摘　　要：大气环境下溶液法制备的CsPbIBr_(2)钙钛矿薄膜存在薄膜覆盖率低、结晶度差和性能不稳定性等问题.为此,本文提出了一种双配体(卵磷脂(L-α-phosphatidylcholine,LP)和硫氰酸铵(NH_(4)SCN))策略,可在相对湿度不高于60%的大气环境下,利用喷涂法制备出高结晶质量、结构稳定的钙钛矿薄膜.这是由于卵磷脂能够有效降低钙钛矿前驱体溶液的表面张力,提高CsPbIBr_(2)钙钛矿薄膜的覆盖率,并在CsPbIBr_(2)钙钛矿薄膜表面形成一层隔绝水氧的保护层;但同时也会减小晶粒尺寸,形成大量的晶界,造成载流子传输不利.而NH_(4)SCN能够克服卵磷脂的不足,增大晶粒尺寸,提高钙钛矿材料的电学特性.这样,制备出的未封装CsPbIBr_(2)钙钛矿光电探测器(ITO/CsPbIBr_(2)/Au)具有低暗电流密度(2×10^(-4) mA·cm^(-2))、微秒级别的响应时间(20,21µs)和长效稳定性(在相对湿度为40%—60%的大气环境下,储存70天后,仍能保持原光暗电流初始值的81%)等特性.The CsPbIBr_(2) perovskite films deposited from the precursor solutions in air,usually suffer poor surface coverage and air-stability due to the uncontrolled nucleation and the existence of I-during the film formation,resulting in terrible photoelectric characteristics and reproducibility.At present,the high-quality CsPbIBr_(2) films are prepared under nitrogen atmosphere,which results in the increase of the cost and thus impedes their applications in air.Here in this work,we propose a strategy for growing the perovskite films with low defect density and better stability in air via dual-ligand-assisted(ligand 1(LP)and ligand 2(NH_(4)SCN))solution strategy.These ligands contain some organic molecules which have strong interaction with ions on the surface of perovskite thin film in order to regulate the addition of precursor ions onto the films.The high-quality CsPbIBr_(2) thin films are prepared in air with relative humidity of≤60%by the spraying method.The results indicate that ligand 1 with hydrophilic group and hydrophobic group,a kind of surfactant,can effectively reduce the surface tension of perovskite precursor solution,improve the coverage of CsPbIBr_(2) perovskite film,and form a block layer of water and oxygen.However,the addition of ligand 1 in precursor solution inevitably introduces many grain boundaries,which is unfavorable for carrier transport and collection.Thus,ligand 2 is employed to control the nucleation of perovskite film as another ligand,resulting in reducing the point defect formation.Their combination is beneficial to forming the uniform perovskite film with large-size crystal and low-density defect.The high-quality crystallization of the perovskite film is found to simultaneously enhance the response and the durability of photodetectors.Thus,the unpackaged photodetectors(ITO/CsPbIBr_(2)/Au)based on this strategy yield the outstanding photoelectric response under the excitation of 405 nm laser.This device exhibits a low dark current density of 2×10^(-4) mA/cm^(2),a fast response time o

关 键 词：双配体策略 无机钙钛矿材料 光电探测器 

分 类 号：TN15[电子电信—物理电子学]