沉积参数对铯铅溴钙钛矿薄膜中CsPb_(2)Br_(5)相结构演变和发光特性的影响

Effect of Deposition Parameters on Luminescence Properties and Structure Evolution of CsPb_(2)Br_(5) Phase in Cesium Lead Bromide Perovskite Films

基于化学气相沉积(CVD)法制备的铯铅溴钙钛矿薄膜具有优异的光电特性,然而薄膜通常存在CsPbBr_(3)和CsPb_(2)Br_(5)两个不同的相结构区域。本文通过CVD法制备了铯铅溴钙钛矿薄膜,并利用X射线衍射(XRD)、扫描电镜(SEM)、电子能谱仪(EDS)及荧光光谱仪研究了反应气压与N_(2)流量对其中的CsPb_(2)Br_(5)相结构的影响。实验结果表明,反应气压的变化对CsPb_(2)Br_(5)相结构无影响;与此不同,随着N_(2)流量的减少,薄膜中部分CsPb_(2)Br_(5)相结构逐渐转变为CsPbBr_(3)相结构,其发光也由以~630 nm为主的宽带发射转变为以~530 nm为主的窄带发射。实验表明,N2流量是调控CsPb_(2)Br_(5)相结构和发光特性的有效手段。

The cesium lead bromide perovskite thin films prepared by chemical vapor deposition(CVD)have excellent optoelectronic properties,but the thin films generally have two different phase structures,CsPbBr_(3) and CsPb_(2)Br_(5).In our work,CVD method is considered to prepare cesium lead bromide perovskite thin films,and the effects of reaction pressure and N2 flow on CsPb_(2)Br_(5) in the thin films were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and fluorescence spectrometer.The results show that the change of the reaction pressure has no effect on the CsPb_(2)Br_(5) phase.However,with the decrease of the N_(2) flow,part of the CsPb_(2)Br_(5) phase in the film gradually transforms into the CsPbBr_(3) phase,and its luminescence also converts from a broadband emission dominated by~630 nm to a narrowband emission dominated by~530 nm.Experimental results reveal that N_(2) flow is an effective means to control the phase structure and luminescence properties of CsPb_(2)Br_(5).