Robust Tin‐Based Perovskite Solar Cells with Hybrid Organic Cations to Attain Efficiency Approaching 10

• Published in: Advanced materials (Weinheim) Vol. 31; no. 2; pp. e1804835 - n/a
• Main Authors: Jokar, Efat, Chien, Cheng‐Hsun, Tsai, Cheng‐Min, Fathi, Amir, Diau, Eric Wei‐Guang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.01.2019
• Subjects: additives; Cations; Crystal structure; Efficiency; Energy conversion efficiency; guanidinium; hybrid cations; lead‐free perovskites; Materials science; Perovskites; Photovoltaic cells; Solar cells; Stability; hybrid cations; lead-free perovskites; solar cells; additives; guanidinium
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201804835

The stability of a tin‐based perovskite solar cell is a major challenge. Here, hybrid tin‐based perovskite solar cells in a new series that incorporate a nonpolar organic cation, guanidinium (GA+), in varied proportions into the formamidinium (FA+) tin triiodide perovskite (FASnI3) crystal structure in the presence of 1% ethylenediammonium diiodide (EDAI2) as an additive, are reported. The device performance is optimized at a precursor ratio (GAI:FAI) of 20:80 to attain a power conversion efficiency (PCE) of 8.5% when prepared freshly; the efficiencies continuously increase to attain a record PCE of 9.6% after storage in a glove‐box environment for 2000 h. The hybrid perovskite works stably under continuous 1 sun illumination for 1 h and storage in air for 6 days without encapsulation. Such a tin‐based perovskite passes all harsh standard tests, and the efficiency of a fresh device, 8.3%, is certified. The great performance and stability of the device reported herein attains a new milestone for lead‐free perovskite solar cells on a path toward commercial development. Hybrid cation (guanidinium/formamidinium) tin‐based perovskites that give a new performance record for lead‐free perovskite solar cells (power conversion efficiency = 9.6%) are demonstrated. The fabricated devices show an incredible light‐soaking stability for continuous 1 sun illumination for 1 h, and the device passes all harsh verification steps to attain a certified efficiency of 8.3% for a fresh cell.