摘要
全无机CsPbBr3钙钛矿太阳能电池中的电荷传输层与钙钛矿层界面的载流子复合是制约其光电转换效率进一步提升的关键因素。文中采用带隙和带边可调控的二维过渡金属硫族化合物(MoS_(2)、MoSe_(2)、WS_(2)和WSe_(2))材料作为电子传输层和钙钛矿层之间的界面修饰材料和载流子传输材料,利用晶格匹配的范德华外延生长高质量的钙钛矿薄膜,同时通过界面能级补偿和势垒消减,降低钙钛矿层与电子传输层之间的界面电荷损失,促进全无机CsPbBr3钙钛矿太阳能电池器件中载流子的提取与传输,使器件光电转换效率由初始的7.94%提高到10.02%,同时开路电压从1.474 V提升至1.567 V。该研究为制备高质量的钙钛矿薄膜同时实现界面能级匹配的高性能光电器件提供了一条新途径。
Objective As a new generation photovoltaic technology,perovskite solar cells(PSCs)have achieved a comparable efficiency to commercial silicon-based solar cells,demonstrating great application potential.However,these photoactive layers based on organic-inorganic hybrid perovskites are very unstable,which seriously hinders their commercial application.Therefore,all-inorganic CsPbBr_(3)perovskite has attracted enormous attention due to its outstanding environmental tolerance to heat,moisture,oxygen and UV light.Unfortunately,the device efficiency based on CsPbBr_(3)perovskite is relatively lower compared to that of the PSCs device with organic-inorganic hybrid perovskites.The recombination of charge carriers at the interface between the charge transport layers and the perovskite layer in all-inorganic CsPbBr_(3)PSCs is the key factor that restricts the further improvement of its photoelectric conversion efficiency(PCE).In recent years,two-dimensional transition metal dichalcogenides(TMDCs)materials represented by MoS_(2),MoSe_(2),WS_(2)and WSe_(2)have attracted more and more attention due to their unique physical and chemical properties.With the advantages such as adjustable band gap and band edge,high carrier mobility,stable chemical properties and matching energy level with perovskite materials,two-dimensional TMDCs are regarded as effective interface modification materials to promote interface charge extraction in all inorganic CsPbBr_(3)PSCs.However,the current research on using twodimensional materials as interface modification layers and charge carrier transport layers in all-inorganic PSC is still in its infancy.Methods Through interface engineering,various two-dimensional TMDCs(MoS_(2),MoSe_(2),WS_(2),and WSe_(2))materials are introduced at the interface between the perovskite layer and the electron transport layer of the allinorganic CsPbBr_(3)PSCs with an FTO/SnO_(2)/TMDCs/CsPbBr_(3)/C structure.The two-dimensional TMDCs here act as both interface modification materials and carrier transport layers.Through interface level compensation and barrier reduction with TMDCs interlayers,the carrier extraction and transport in all-inorganic CsPbBr_(3)PSC devices are promoted(Fig.1).Moreover,by constructing TMDCs/CsPbBr_(3)van der Waals heterostructure,highquality CsPbBr_(3)perovskite thin films with large and compact grains are grown via lattice matched van der Waals epitaxy(Fig.5).Results and Discussions The interface charge loss between the perovskite layer and the electron transport layer is reduced,and the carrier extraction in the all-inorganic CsPbBr_(3)PSC devices are enhanced,so that the PCE of the devices is increased from the initial 7.94%to 10.02%,and the open-circuit voltage is increased from 1.474 V to 1.567 V(Fig.8).In addition,Mott-Schottky curves are measured in the dark by performing capacitance-voltage characterization,which demonstrates an enhanced built-in potential,indicating the enlarged driving force for charge transportation with TMDCs/CsPbBr_(3)heterostructure(Fig.9).Finally,the time-resolved photoluminescence decay measurements are performed to investigate the photoluminescence decay lifetimes,which are closely related to the electron extraction ability.Due to better energy level matching of TMDCs with perovskite layers,CsPbBr_(3)perovskite layers show shorter carrier lifetimes on TMDCs interlayer(Fig.10),which further confirms the enhanced electron extraction ability from perovskite to the electron transport layer.Conclusions A novel strategy is developed to prepare high-quality perovskite films by constructing TMDCs/CsPbBr_(3)van der Waals heterostructure and achieve high-performance photoelectric devices through interfacial energy level matching,which provides a new way for the development of all-inorganic perovskite optoelectronic devices based on two-dimensional TMDCs materials.
作者
周青伟
吴凡
罗芳
黄先燕
郭楚才
朱志宏
Zhou Qingwei;Wu Fan;Luo Fang;Huang Xianyan;Guo Chucai;Zhu Zhihong(College of Advanced Interdisciplinary Studies&Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices,National University of Defense Technology,Changsha 410073,China;Nanhu Laser Laboratory,National University of Defense Technology,Changsha 410073,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2023年第6期294-303,共10页
Infrared and Laser Engineering
基金
国家自然科学基金(52101257)。
关键词
太阳能电池
光电性能
二维界面修饰
钙钛矿
过渡金属硫族化合物
solar cells
photoelectric property
two-dimensional interface modification
perovskite
transition metal chalcogenides
