Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells
Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells
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DOI：
10.1039/c3ee43822h
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发表时间：
2014-03-01
影响因子：
32.5
通讯作者：
Snaith, Henry J.
中科院分区：
文献类型：
--
作者：
Eperon, Giles E.;Stranks, Samuel D.;Snaith, Henry J.
基于钙钛矿的太阳能电池最近引起了人们的极大兴趣，其功率转换效率超过 15%，已经取代了许多成熟的薄膜太阳能电池技术。大多数工作都集中在甲基铵三卤化铅钙钛矿上，其带隙约为 1.55 eV 甚至更大。在这里，我们探索了取代这种钙钛矿中的甲基铵阳离子的效果，并表明用稍大的甲脒阳离子，我们可以合成带隙在 1.48 至 2.23 eV 之间可调的甲脒三卤化铅钙钛矿。我们认为 1.48 eV 带隙钙钛矿最适合单结太阳能电池，并证明了该材料的长程电子和空穴扩散长度，使其适合平面异质结太阳能电池。我们制造了此类器件，由于带隙减小，我们实现了 >23 mA cm(-2) 的高短路电流，从而使功率转换效率高达 14.2%，这是溶液处理平面异质结钙钛矿太阳能电池迄今为止的最高效率。因此，甲脒三碘化铅有望成为此类太阳能电池的新候选者。
Perovskite-based solar cells have attracted significant recent interest, with power conversion efficiencies in excess of 15% already superceding a number of established thin-film solar cell technologies. Most work has focused on a methylammonium lead trihalide perovskites, with a bandgaps of similar to 1.55 eV and greater. Here, we explore the effect of replacing the methylammonium cation in this perovskite, and show that with the slightly larger formamidinium cation, we can synthesise formamidinium lead trihalide perovskites with a bandgap tunable between 1.48 and 2.23 eV. We take the 1.48 eV-bandgap perovskite as most suited for single junction solar cells, and demonstrate long-range electron and hole diffusion lengths in this material, making it suitable for planar heterojunction solar cells. We fabricate such devices, and due to the reduced bandgap we achieve high short-circuit currents of >23 mA cm(-2), resulting in power conversion efficiencies of up to 14.2%, the highest efficiency yet for solution processed planar heterojunction perovskite solar cells. Formamidinium lead triiodide is hence promising as a new candidate for this class of solar cell.