Exploring performance limits toward 20.79% efficiency in 2D-layered Ruddlesden–Popper perovskite solar cells

Abstract

Two-dimensional Ruddlesden–Popper (2DRP) halide perovskites have attracted considerable interest in photovoltaics due to their optoelectronic properties and superior environmental stability. Herein, a 2-(methylthio)ethylamine (MTEA⁺) bulky spacer was introduced as the organic interlayer with sulfur–sulfur bonding, which interacted electrostatically with the inorganic framework to induce the oriented (MTEA)₂(MA)₄Pb₅I₁₆ 2DRP perovskite and lattice stabilization. We demonstrated, through numerical simulations, that the performance of 2DRP-based perovskite solar cells (PSCs) could be improved by adapting the perovskite film thickness, trap-state density, parasitic resistances, and temperature. Optical analyses revealed that the 2DRP perovskite dominated light-harvesting in the visible spectrum, while charge transport materials remained largely transparent. PSCs with 2DRP (n = 5) showed a maximum power conversion efficiency (PCE) of 20.79% with an outstanding open circuit voltage (V_OC) of 1.49 V under standard AM1.5G illumination. Moreover, the proposed simulation predicted potentially improved thermal stability for the optimized device, theoretically retaining 95% of its initial performance. A simulated PCE of 20.79% represented a theoretical upper limit achievable only under optimized charge dynamic conditions.