Effects of Residual DMSO Adduct on Photonically Cured MAPbI3 Solar Cells

Defects and impurities in halide perovskite solar cellscan negativelyimpact device performance and long-term stability. In this study,we identify photonically cured methylammonium (MA) lead iodide filmscontaining a residual adduct, MA(2)Pb(3)I(8)(dimethyl sulfoxide)(2) (MA(2)Pb(3)I(8)(DMSO)(2)), which reduces photocurrent generationin perovskite solar cells (PSCs). This is evidenced by a decreasein the external quantum efficiency (EQE) near 400 nm. Similar EQEreductions were observed in PSCs produced using high-speed processesbut have not been thoroughly examined. Through X-ray diffraction patternsand Fourier transform infrared spectroscopy, we establish the photoinactiveMA(2)Pb(3)I(8)(DMSO)(2) as theculprit for the EQE reduction. Combined experimental and simulationresults reveal that the MA(2)Pb(3)I(8)(DMSO)(2) phase is located at the hole transport layer/interface, noton the surface, resulting in lower quantum efficiency and surfacephotovoltage in the short-wavelength region. The residual adduct iskinetically trapped due to the short processing time (20 ms) and crystallizationdirection but can be removed by an additional photonic pulse. Thisstudy highlights the need for careful examination of resulting materialsbeyond device efficiency when transitioning from laboratory processingto industrial high-speed methods.