Fabrication of Affordable, Efficient, and Sustainable Carbon Electrode-based HTL-free Perovskite Solar Cells Using Azole Salts as Additive Material

Perovskite solar cells (PSCs) are acclaimed as remarkable devices for converting light into electricity. The crystallinity of the perovskite layer defines its performance, efficiency, and stability. Defects/trap states may negatively affect photovoltaic device performance. Using additives can enhance the power conversion efficiency (PCE) and the durability of PSCs. The additive approach reduces defects at the perovskite film surface and grain boundaries. In this study, we introduce 1,2,4-triazole (TZL) into a perovskite precursor solution to improve the quality of the perovskite film, larger crystal grains, crystalline structures, PCE, and longevity of carbon-based PSCs. The presence of three nitrogen atoms in TZL strengthens the hydrogen bonding in the perovskite structure, enhancing the material stability. TZL efficiently reduces defects/traps, potentially enhancing charge carrier transportation, and minimizes the nonradiative recombination resulting in enhanced durability, efficiency, and performance of PSCs. Carbon-based PSCs with 5 mg TZL added had an improved PCE of 10.66% when compared to the control MAPbI3 PSCs (8.32%). Furthermore, 5 mg TZL greatly improves the long-term stability (under the condition of 30 °C and RH = 50% ± 5%) of CPSCs, allowing them to retain 85% of their initial PCE after 500 h of preservation. Our results demonstrate that the TZL additive approach improves perovskite film quality, CPSC performance, and durability.