Fully 2D heterojunction perovskite photovoltaics using chalcogenides

Abstract

Two-dimensional halide perovskites are emerging optoelectronic semiconductors because of their tunable photophysical characteristics and enhanced environmental stability relative to three-dimensional perovskites. Herein, we design perovskite solar cells in which both charge transporting layers and the perovskite are on two-dimensional semiconductors, providing atomically sharp interfaces and suppressed interfacial defects. The proposed solar cells employ a Dion–Jacobson perovskite with a thiophene-based bulky diammonium aromatic spacer, (ThDMA)MA_n−1Pb_nI_3n+1 with nominal n = 5, which is combined with molybdenum disulfide and tungsten disulfide as electron and hole charge transporting layers. After optimization of the perovskite layer of the designed solar cells, the n = 5 Dion–Jacobson device delivers a champion efficiency of 17.13% with a remarkably high open-circuit voltage of 1.25 V and a fill factor of 81.07%. The high device performance was achieved with a perovskite layer thickness of 200 nm, trap-state density of 10¹⁴ cm⁻³, charge carrier mobility of 0.1 cm² V⁻¹ s⁻¹, series resistance of 2.0 ohm cm², shunt resistance of 5000 ohm cm², and operating temperature of 300 K. Importantly, the optimized cell maintained 83% of its original efficiency at 400 K. This work provides significant directions for future advancements toward high-performance low-dimensional perovskite photovoltaics.