Phase Pure 2D Perovskite for High‐Performance 2D–3D Heterostructured Perovskite Solar Cells

• Published in: Advanced materials (Weinheim) Vol. 30; no. 52; pp. e1805323 - n/a
• Main Authors: Li, Pengwei, Zhang, Yiqiang, Liang, Chao, Xing, Guichuan, Liu, Xiaolong, Li, Fengyu, Liu, Xiaotao, Hu, Xiaotian, Shao, Guosheng, Song, Yanlin
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.12.2018
• Subjects: 2D–3D heterojunctions; carrier dynamics; Carrier mobility; Charge efficiency; Crystal lattices; Current carriers; diffusion length; Efficiency; Energy conversion efficiency; Grain boundaries; Heterostructures; Localization; Microcrystals; perovskite solar cells; Perovskites; Photovoltaic cells; Quantum confinement; Solar cells; Stability; diffusion length; 2D-3D heterojunctions; carrier dynamics; perovskite solar cells; stability
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.201805323

Three‐dimensional (3D) metal‐halide perovskite solar cells (PSCs) have demonstrated exceptional high efficiency. However, instability of the 3D perovskite is the main challenge for industrialization. Incorporation of some long organic cations into perovskite crystal to terminate the lattice, and function as moisture and oxygen passivation layer and ion migration blocking layer, is proven to be an effective method to enhance the perovskite stability. Unfortunately, this method typically sacrifices charge‐carrier extraction efficiency of the perovskites. Even in 2D–3D vertically aligned heterostructures, a spread of bandgaps in the 2D due to varying degrees of quantum confinement also results in charge‐carrier localization and carrier mobility reduction. A trade‐off between the power conversion efficiency and stability is made. Here, by introducing 2D C6H18N2O2PbI4 (EDBEPbI4) microcrystals into the precursor solution, the grain boundaries of the deposited 3D perovskite film are vertically passivated with phase pure 2D perovskite. The phases pure (inorganic layer number n = 1) 2D perovskite can minimize photogenerated charge‐carrier localization in the low‐dimensional perovskite. The dominant vertical alignment does not affect charge‐carrier extraction. Therefore, high‐efficiency (21.06%) and ultrastable (retain 90% of the initial efficiency after 3000 h in air) planar PSCs are demonstrated with these 2D–3D mixtures. High‐efficiency (21.06%) and durable 2D–3D vertical aligned perovskite solar cells (PSCs) with phase pure 2D perovskite are demonstrated. The phase pure 2D perovskite minimizes photo‐generated charge‐carrier localization in the low‐dimensional perovskite; the dominant vertical alignment does not affect charge‐carrier extraction. The traditional constraint of trade‐off between efficiency and stability in PSC is overcome.