利用PNA添加剂来调控钙钛矿薄膜结晶和覆盖率实现高效太阳能电池（英文）

Tuning The Crystal-growth and Coverage of Perovskite Thin-films for Highly Efficient Solar Cells by Using Polyacrylonitrile Additive

钙钛矿薄膜形貌的控制是一个提高太阳能电池能量转换效率的关键问题,而引入添加剂是解决这一问题的一种有效而简便的方法。利用聚丙烯腈(PNA)作为CH_3NH_3PbI_3前驱体溶液溶剂添加剂,通过其浓度可以调控钙钛矿薄膜结晶和表面的覆盖率。本文通过SEM、XRD以及UV-Vis研究了PNA掺杂CH_3NH_3PbI_3钙钛矿薄膜后的表面形貌、结晶度和光学性能的变化。结果表明,通过添加少量的PNA可以优化钙钛矿薄膜的性能,其强烈影响薄膜的结晶过程,有助于形成均匀连续的薄膜,减少针孔,从而增强了钙钛矿层的覆盖率和光吸收。当PNA的含量为1%(质量分数)时,钙钛矿太阳能电池的各项性能最佳,能量转换效率达到了8.38%。与未加PNA的电池效率(1.31%)相比,提高了540%。这些结果表明,PNA可以有效调控钙钛矿薄膜的晶体生长和薄膜形貌,在钙钛矿太阳能电池的大规模生产过程中是一种可以改善钙钛矿薄膜质量的有效添加剂。

For perovskite solar cells,the morphology control of the perovskite thin-films is one of the key questions for improving the power conversion efficiency（PCE）. To solve this issue,introduction of additive is proved to be an effective and simple way. Herein,polyacrylonitrile（PAN） was used as a solvent additive in the one-step CH_3NH_3PbI_3precursor solution,and the crystallization and surface coverage of the CH_3NH_3PbI_3films were controlled by means of adjusting its concentration,by means of adjusting its concentration to control the crystallization and surface coverage of the CH_3NH_3PbI_3films. Meanwhile,the film crystallinities,morphologies,and optical properties of CH_3NH_3PbI_3perovskite layers are characterized by scanning electron microscopy（SEM） and X-ray diffraction（XRD） and UV-Vis. These experiment results show that the perovskite film properties can be optimized just by combining a small number of PAN,and PAN can strongly influence the crystallization process of forming pure CH_3NH_3PbI_3and facilitate forming the homogenous continuous films with fewer pinholes,which leads to a strengthened crystallization of CH_3NH_3PbI_3and remarkably improved coverage and light absorption of CH_3NH_3PbI_3on a planar substrate. After adding 1% mass fraction of PAN,the optimized PCE of CH_3NH_3PbI_3solar cells was increased from 1. 31% to 8. 13% for the planar cell structure. These results prove that PNA is an effective additive which could improve the quality of perovskite thin-films and potentially be a new candidate as an easily accessible additive during perovskite solar cells mass production.