有机铵盐表面稳定化CsPbI2Br全无机钙钛矿  

Organic ammonium salt surface treatment stabilizing all-inorganic CsPbI2Br perovskite

作　　者：刘晓敏 李亦回 王兴涛 赵一新[1] Liu Xiao-Min;Li Yi-Hui;Wang Xing-Tao;Zhao Yi-Xin(School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学环境科学与工程学院

出　　处：《物理学报》2019年第15期142-148,共7页Acta Physica Sinica

摘　　要：有机-无机杂化钙钛矿中的有机阳离子组分具有在光照和加热条件下本征的化学不稳定性,而全无机钙钛矿有望从根本上解决组分稳定性问题.但是,全无机钙钛矿在湿度条件下,极易相变为非光学活性的d相.本文以CsPbI2Br全无机钙钛矿为对象,研究不同碳链长度的有机铵盐表面处理对于钙钛矿湿稳定性和器件光电性能的影响.实验结果表明,有机铵盐碳链的增长显著改善钙钛矿相稳定性.其中,当用碘化丁铵处理时,CsPbI2Br全无机钙钛矿表现出最佳的湿稳定性.随着碘化丁铵的处理浓度的增加,钙钛矿的湿稳定性进一步改善.当用适宜浓度的碘化丁铵处理CsPbI2Br薄膜时,钙钛矿层表层的丁铵阳离子对电荷传输不会有明显阻碍,可以获得优良的器件效率.总之,适宜的有机阳离子层既能提高全无机钙钛矿的湿稳定性,又能改善其光伏性能.All-inorganic perovskite cesium lead halides with superior stability,suitable bandgap and high absorption efficient have become a promising candidate for photovoltaic application.In all-inorganic cesium lead halide perovskites,CsPbX3(X=Br,I)exhibits excellent photoelectric properties,which are similar to those of organic-inorganic hybrid perovskites.The CsPbI3 faces a challenge of unideal tolerant factor for perovskite phase while CsPbI3–xBrx has better tolerant factor.Among them,CsPbI2Br is one of most popular candidates because of its good thermal stability.Nevertheless,CsPbI2Br shows instability due to the phase transition caused by moisture and lower efficiency because of defects.For all inorganic perovskite devices,the alkyl chain length of surface treatment agent should be taken into account when using organic cationic passivation method.In this paper,CsPbI2Br perovskite is treated with different organic ammonium salts to enhance its phase stability.The experimental results show that a-phase CsPbI2Br is more stable with the increase of the alkyl chain length.Butylamine iodine(BAI)among three kinds of surface treating agents is proved to have the best defect passivation and phase stabilization effect.With the increase of alkyl chain length,the hydrophobicity of the organic molecular layer increases,which plays a crucial role in protecting optically active CsPbI2Br.Meanwhile,it is found that the stability of perovskite is enhanced with the concentration of the BAI solution increasing.This should be related to the organic cation termination formed on the surface of CsPbI2Br film.Solar cell devices based on the CsPbI2Br thin films treated with different concentrations of BAI are assembled and then the effect of organic ion surface treatment on the photoelectric performance of batteries is further explored.The experimental results show that when the concentration of BAI is relatively high(4 mg/mL and 8 mg/mL),the device’s photovoltaic performance decreases especially the photocurrent obviously decreases,whil

关 键 词：钙钛矿太阳能电池 湿稳定性 铵盐 

分 类 号：TM914.4[电气工程—电力电子与电力传动]