钙钛矿薄膜的微结构和光电特性优化

Optimization of Microstructure and Photoelectric Properties of Perovskite Thin Films

分别以纯二甲基甲酰胺、纯二甲基亚砜以及二者不同比例的混合物作为前驱体溶剂,制备钙钛矿薄膜样品.将薄膜样品分为两组,分别将其置于氮气氛围中进行热退火和二甲基亚砜蒸汽氛围中进行溶剂退火,并对薄膜样品的微观结构和光电特性进行系统研究分析.结果表明,与热退火相比,经溶剂退火后样品的平均晶粒尺寸和均匀性显著提升,从而减小了薄膜中晶粒边界或界面的体积分数.采用混合前驱体溶剂和后续溶剂退火增加了薄膜的厚度和可见光的利用率,有效改善了薄膜形貌,优化了结晶质量.同时薄膜光致发光强度的增加,表明薄膜缺陷态密度降低.采用优化后的钙钛矿薄膜作为吸收层制备太阳电池,其光电转换效率达到15.7%.

Using the pure N,N-dimethyl formamide,pure dimethyl sulfoxide and mixed solvents with different proportion as precursor solvent,respectively,the perovskite thin film samples were prepared.The samples were divided as two sets,one set was processed by thermal annealing in N2 atmosphere,while the other set was processed by solvent annealing in dimethyl sulfoxide vapor atmosphere.The microstructure and optoelectronic properties of the samples were systematically analyzed.The results show that,compared with the thermal annealing,the grain size and uniformity of samples can be significantly improved by solvent annealing,which reduces volume fraction of grain boundaries or interfaces in the films.By solvent annealing and mixed solvents,the absorption and utilization ratio of visible light are enhanced,the morphology is improved,and the crystallization quality is optimized.The increasing of photoluminescence intensity indicates that the defect densities of thin film are reduced.Thin film solar cells were fabricated using the optimized perovskite film as the absorber layer,and a conversion efficiency of 15.7% was achieved.