利用混合溶剂实现钙钛矿材料微观结构和光电性能优化  

Improving Microstructure and Photoelectric Performance of the Perovskite Material via Mixed Solvents

作　　者：郭秀斌[1] 于威[1] 李婧[1] 蒋昭毅 马登浩[2] 刘海旭[1] 

机构地区：[1]河北大学物理科学与技术学院,河北省光电信息材料重点实验室,保定071002 [2]北京航空航天大学物理科学与核能工程学院,北京100191

出　　处：《无机材料学报》2017年第8期870-876,共7页Journal of Inorganic Materials

基　　金：国家自然科学基金(51572008)~~

摘　　要：采用纯N,N-二甲基甲酰胺(DMF)溶剂、纯二甲基亚砜(DMSO)溶剂以及DMSO/DMF不同体积比例混合溶剂制备钙钛矿(CH_3NH_3PbI_3)薄膜,并系统研究了不同溶剂对钙钛矿薄膜微结构及光电特性的影响。结果表明,随着DMSO在混合溶剂中比例增加,钙钛矿薄膜平均晶粒尺寸增大,碘化铅(PbI_2)残留量降低,同时薄膜中有序的钙钛矿晶体所占比例呈现先增大后减小的趋势,并且当DMSO占混合溶剂体积比为60%时达到最大。薄膜Urbach能,载流子寿命以及PbI_2含量之间的关系表明,微量的PbI_2可有效钝化钙钛矿薄膜的缺陷。经过优化后(DMSO占混合溶剂体积比为30%),钙钛矿太阳电池的光电转换效率达到15.1%(VOC=0.99 V;JSC=20.9 m A/cm^2;FF=0.73)。The perovskite （CH3NH3PbI3） thin films were prepared with pure N, N-dimethyl formamide （DMF）, pure dimethyl sulfoxide （DMSO） and their mixtures with different volume ratios. The impact of different solvents on the microstructure and photoelectric properties of perovskite materials was systematically investigated. Results show that with the increase of DMSO in mixed solvents, the average grain size of CH3NH3PbI3 increases while the residual lead iodide （PbI2） decreases. Moreover, the ratio of ordered CH3NH3PbI3 crystals increases firstly and then decreases, and the highest ratio is achieved when the volume ratio of DMSO in mixed solvent is 60%. In addition, the relationship among Urbach energy characterization, time-resolved photoluminescence characterization and unreacted PbI2 residue indicates that the trace amounts of PbI2 may effectively passivate the defects in perovskite thin films, so as to prolong the carrier lifetime. The inverted planar heterojunction perovskite thin film solar cells were fabricated. The highest power conversion efficiency （PCE） of 15.1% （Voc=0.99 V; Jsc=20.9 mA/cm2; FF=0.73） is achieved when the volume ratio of DMSO in mixed solvent is 30%. These results reveal that mixed solvents with appropriate volume ratio is fa- vorable for the improvement of microstructure and photoelectric properties of perovskite materials.

关 键 词：混合溶剂 钙钛矿 光电特性 钝化 

分 类 号：O472[理学—半导体物理]