A Universal Method of Perovskite Surface Passivation for CsPbX3 Solar Cells with VOC over 90% of the S‐Q limit. (21st August 2022) - Guo, Zhanglin
Abstract: In comparison to hybrid perovskite solar cells (PSCs), all‐inorganic CsPbX3 PSCs suffer from larger V OC deficits, leading to inferior efficiency. The perovskite surface defects like iodine vacancy (VI ) are the main sources of nonradiative recombination causing a V OC deficit. Here, 2, 5‐thiophenedicarboxylic acid (TDCA) is used to passivate the surface VI through the strong coordination interaction between the thiophene unit of TDCA and the undercoordinated Pb 2+ of perovskite. TDCA passivation also elevates the perovskite surface valence band position, leading to a better interfacial energy alignment. Consequently, the V OC of CsPbI2.25 Br0.75 PSCs is remarkably improved from 1.36 to 1.43 V (efficiency from 15.55% to 16.72%), reaching 92% (record‐high among CsPbX3 PSCs) of the Shockley–Queisser V OC limit. This method also promotes the V OC of CsPbI1.5 Br1.5 cell from 1.42 to 1.51 V (90% of the limit) and CsPbIBr2 cell from 1.44 to 1.54 V (87% of the limit), demonstrating its universality for CsPbX3 perovskites. Abstract : A universal perovskite surface passivation method using 2, 5‐thiophenedicarboxylic acid is developed, by which the V OC of different CsPbX3 solar cells are highly enhanced, leaving extremely small V OC deficits.