Overcoming photovoltage deficit via phenylthiourea derivatives for efficient printed perovskite solar cells with enhanced stability

Abstract Although the certified power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has achieved a high level of 27%, approaching the single-crystalline silicon solar cells, the device stability remains an urgent issue to be resolved for the commercialization. Defect passivation emerged as a viable approach to enhance the operational stability of the solar devices. Herein, phenylthiourea (PhTu) derivatives are selected as effective passivation agents to enhance the optoelectronic properties of printed methylammonium lead iodide (MAPbI 3 ) films. It is demonstrated that incorporating a small amount of 1-(4-carboxyphenyl)-2-thiourea (PhTu-COOH) significantly reduces the trap-state density and leads to longer carrier lifetime of the perovskite films. As a result, the inverted solar device made of PhTu-COOH-modified MAPbI 3 perovskite film shows remarkably improved efficiency (from 17.29% to 20.22%) and obviously increased open-circuit voltage ( V OC ) (from 1.043 to 1.143 V), as compared with the pristine device. Moreover, the PhTu-COOH-modified PSCs exhibit enhanced operational stability due to the significantly reduced trap-state density. Finally, the optimized solar module fabricated with an active area of 11.28 cm 2 delivers a high PCE of 17.07% with negligible V OC loss, demonstrating the feasibility of the blade-coating method for large-area perovskite film deposition.