Optimized crystallization and defect passivation with Yttrium (III) doped MAPbBr3 film for highly efficient and stable hole-transport-layer-free carbon-based perovskite solar cells

The preparation of high-quality perovskite films with low defect density and long carrier lifetime is a precondition for achieving high-efficiency perovskite solar cells (PSCs). In this work, we successfully incorporated Y 3+ ions into perovskite films to enhance the photovoltaic performance of hole-transport-layer-free (HTL-free) carbon-based MAPbBr 3 PSCs in ambient atmosphere. The perovskite films exhibit better crystallinity, lower trap density, and longer carrier lifetime after the introduction of Y 3+ ions. By optimizing the doping dosage, a maximal power conversion efficiency (PCE) of 8.313% (open-circuit voltage ( V OC ) = 1.562 V) is achieved for MAPb 0.98 Y 0.02 Br 3 PSCs. Moreover, the unencapsulated device also shows remarkable long-term stability over 80 days under dry condition with 20–30% relative humidity (RH) at 20–25 °C, which even maintains 95% of its initial PCE when stored in harsh environment (80 °C and 40–70% RH) over 72 h.