溶液法制备CsPbBr钙钛矿薄膜微观结构控制与发光特性

Microstructure and Luminescence Characteristics of CsPbBr3 Perovskite Films by Solution Process

近年来,金属卤化物钙钛矿以其光吸收系数高、色纯度高、色域广、发光波长连续可调、光致发光量子产率高、载流子扩散长度大和成分稳定不易分解等优点,成为光电子应用领域极具潜力的新材料,其在太阳能电池、发光二极管、忆阻器、激光器、光电探测器和防伪标签等方面均有出色的表现,并且可通过简单的全溶液法制备,为印刷工艺的结合、大尺寸生产和产业化提供了可能。实验采用一步溶液法制备了原位生长的溴化铅铯钙钛矿薄膜,其在(100)晶面有择优取向,且相应的晶面间距小于PDF标准卡片值。通过增大前驱液的浓度,使样品的形貌结构产生差异,薄膜的连续性和致密性随之提高,晶粒得到细化,在375 nm激发光下的光致发光(PL)强度得到约5倍的提升,且PL峰位蓝移6 nm,同时该过程导致的晶格畸变使其PL光谱半高宽(FWHM)增大超过2 nm。

In recent years,metal halide perovskites have become new promising materials in the field of optoelectronic applications due to the advantages of high optical absorption coefficient,high color purity,wide color gamut,continuously adjustable luminescence wavelength,high photoluminescence quantum yield,large carrier diffusion length,stable ingredients and not easy to decompose,and have excellent performance in solar cells,light-emitting diodes,memristors,lasers,photodetectors and anti-counterfeiting labels.Furthermore,perovskites can be made by simple methods like solution synthesis,which provides the possibility of combining it with the printing process,large-scale production and industrialization.In this experiment,solution-processed CsPbBr3 perovskite films grown in situ have a preferred orientation on the(100)crystal plane,and its interplanar spacing is smaller than the value from PDF standard card.As the concentration of precursor increases,the morphological structure of samples varied,continuity and compactness of films were improved,crystal grains were refined,the photoluminescence(PL)intensity excited by light at 375 nm was approximately 5 times original,the PL peak position blue shifted by 6 nm,and the lattice distortion caused by this process increased the full width at half maximum(FWHM)of the PL spectrum by more than 2 nm.