High-efficiency solution-processed perovskite solar cells with millimeter-scale grains

• Published in: Science (American Association for the Advancement of Science) Vol. 347; no. 6221; pp. 522 - 525
• Main Authors: Nie, Wanyi, Tsai, Hsinhan, Asadpour, Reza, Blancon, Jean-Christophe, Neukirch, Amanda J., Gupta, Gautam, Crochet, Jared J., Chhowalla, Manish, Tretiak, Sergei, Alam, Muhammad A., Wang, Hsing-Lin, Mohite, Aditya D.
• Format: Journal Article
• Language: English
• Published: Washington American Association for the Advancement of Science 30-01-2015; The American Association for the Advancement of Science; AAAS
• Subjects: Cells; Crystal defects; Devices; Grain; Grain boundaries; MATERIALS SCIENCE; Perovskite; Perovskites; Photovoltaic cells; Semiconductors; Solar cells; Solar energy; Thin films
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aaa0472

State-of-the-art photovoltaics use high-purity, large-area, wafer-scale single-crystalline semiconductors grown by sophisticated, high-temperature crystal growth processes. We demonstrate a solution-based hot-casting technique to grow continuous, pinhole-free thin films of organometallic perovskites with millimeter-scale crystalline grains. We fabricated planar solar cells with efficiencies approaching 18%, with little cell-to-cell variability. The devices show hysteresis-free photovoltaic response, which had been a fundamental bottleneck for the stable operation of perovskite devices. Characterization and modeling attribute the improved performance to reduced bulk defects and improved charge carrier mobility in large-grain devices. We anticipate that this technique will lead the field toward synthesis of wafer-scale crystalline perovskites, necessary for the fabrication of high-efficiency solar cells, and will be applicable to several other material systems plagued by polydispersity, defects, and grain boundary recombination in solution-processed thin films.