Improved Mobility and Photovoltaic Performance of Two-Dimensional Ruddlesden−Popper (thma)2(ma)2m3i10 Perovskites Applied in Perovskite Solar Cells

Two-dimensional Ruddlesden−Popper (2DRP) perovskites have received extensive attention for perovskite solar cells (PSCs) application due to their enhanced thermal and light stability, high photoluminescence quantum yield, and long carrier lifetime. Notably, the power conversion efficiency (PCE) of 2DRP (ThMA)2(MA)2Pb3I10 perovskite is up to19%. However, lead pollution is still a problem that may hinder the development and widespread use of (ThMA)2(MA)2Pb3I10 perovskites. With the aim of revealing lead-free 2DRP alternatives with high photovoltaic performance based on such (ThMA)2(MA)2M3I10 perovskites, metal replacements, such as Cd, Cu, Ge, Ni, Sn, Yb, and Zn, were investigated in terms of their optoelectronic characteristics, carrier transport properties, broadband–emission nature, and photovoltaic parameters from first-principles calculations. Our results indicated that these replacements of Cd, Cu, and Zn can fine-tune the bandgap of (ThMA)2(MA)2M3I10 toward the optimum range required for photovoltaic applications (0.9–1.6 eV). In particular, (ThMA)2(MA)2Cd3I10 and (ThMA)2(MA)2Cu3I10 demonstrated a strong broad–emission nature and photoluminescence tendency due to their large Stokes shifts and Huang-Rhys factors. (ThMA)2(MA)2Ge3I10 and (ThMA)2(MA)2Sn3I10 exhibited the best capacities for electron and hole transport with carrier mobilities of 12.869 and 9.856 cm2 V–1 s–1, respectively, which are 1–2 orders of magnitude higher than that of (ThMA)2(MA)2Pb3I10. Nevertheless, (ThMA)2(MA)2Cu3I10 was predicted to have the highest PCE of 22.97%, featuring itself as a potential photo–absorber candidate for photovoltaic applications. The findings reported herein not only achieve our goal in designing highly efficient and environmentally-friendly 2DRP perovskites, but also shed light on new strategies for advancing their applications in optoelectronic.