Tautomeric Passivation Strategy-Assisted Photostable Perovskite Solar Modules

Defects weaken the stability of perovskite solar modules (PSMs) and aggravate the photodegradation process under continuous illumination (especially, UV light), limiting the competitiveness and commercial development of perovskite photovoltaics. Herein, we propose a tautomeric passivation strategy toward molecular isomerism passivation, 2,3-Bis(2,4,5-trimethyl-3-thienyl) maleimide (DAE), to assist defect passivation for photostable PSMs with sustainable UV protection. The tautomeric DAE molecule in the perovskite film after UV irradiation presents high charge density difference values (−0.182e for −CO–Pb; 0.015e for N–H···I^–) and efficiently improves the defect formation energy, preventing perovskite UV degradation through the free closed and open rings of the DAE molecule in the PSM. The DAE PSCs exhibit champion efficiencies up to 24.12% (small area: 0.08 cm²) and 18.47% (module area: 25 cm²) as well as long-term UV photostability, continuously charging a mobile phone through a DAE-PSM even on a cloudy day.