Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells

• Published in: Nature materials 2014-09, Vol.13 (9), p.897-903
• Main Authors: Jeon, Nam Joong, Noh, Jun Hong, Kim, Young Chan, Yang, Woon Seok, Ryu, Seungchan, Seok, Sang Il
• Format: Article
• Language: English
• Subjects: 639/301/299/946; 639/301/357/551; 639/624; Ammonia; Biomaterials; Cells; Condensed Matter Physics; Fabrication; Inorganic chemistry; Materials Science; Nanotechnology; Optical and Electronic Materials; Organic chemicals; Perovskite; Photovoltaics; Solar cells; Solar energy; Solvents; Toluene
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat4014

Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH 3 NH 3 Pb(I 1  −  x Br x ) 3 ( x = 0.1–0.15) as the absorbing layer and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of γ-butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH 3 NH 3 I–PbI 2 –DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power-conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly efficient perovskite solar cells. The performance of solar cells based on organic–inorganic perovskites strongly depends on the device architecture and processing conditions. It is now shown that solvent engineering enables the deposition of very dense perovskite layers on mesoporous titania, leading to photovoltaic devices with a high light-conversion efficiency and no hysteresis.