Affiliation:
1. Hunan Key Laboratory of Super‐microstructure and Ultrafast Process Hunan Key Laboratory of Nanophotonics and Devices Institute of Super‐microstructure and Ultrafast Process in Advanced Materials (ISUPAM) School of Physics Central South University Changsha Hunan 410083 P. R. China
Abstract
AbstractPolyvinyl pyrrolidone is blended in PbI2 with varied concentration, so as to study the coarsening dynamics of perovskite during the two‐step growth method. It is observed that polyvinyl pyrrolidone hinders the crystallization of PbI2 and helps to form a more amorphous PbI2 matrix, which then improves perovskite crystallization. As the blending concentration increases from 0 to 2 mM, average crystallite/grain size of perovskite increases from 40.29 nm/0.79 µm to 84.35 nm/1.02 µm while surface fluctuation decreases slightly from 25.64 to 23.96 nm. The observations are caused by the “confinement effect” brought by polyvinyl pyrrolidone on PbI2. Elevating blending concentration of polyvinyl pyrrolidone results in smaller PbI2 crystallites and more amorphous PbI2 matrix, thus reducing the diffusion/reaction barrier between PbI2 and organic salt and favoring perovskite crystallization. As blending concentration increases from 0 to 2 mM, the device efficiency rises from 19.76 (± 0.60) % to 20.50 (± 0.89) %, with the optimized value up to 22.05%, which is further improved to 24.48% after n‐Octylammonium iodide (OAI)‐basing surface modification. The study enlarges the scope of “confinement effect” brought by polymer molecules, which is beneficial for efficient and stable perovskite solar cell fabrication.
Funder
National Natural Science Foundation of China
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry
Cited by
3 articles.
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