Exploring the Potential of Solution-Processable AgBiS₂ Quantum Dots as an Efficient Photoactive Material for Eco-Friendly Solar Cell Devices

Lead-free nanocrystals are highly demanding to be implanted in the fabrication of next-generation photovoltaic technologies. Among these, ternary quantum dots (QDs), such as silver bismuth sulfide (AgBiS2), are promising eco-friendly, economical solar cell photoactive materials. Here, we demonstrate the facile synthesis of AgBiS2 through the cation-exchange route and integrate it as a photoactive layer in the solar cell with the architecture glass/ITO/SnO2/AgBiS2/PTAA/MoO3/Ag. The light-harvesting capability of these QDs is then investigated by recording the solar cell’s current–voltage (J–V) measurements. The device exhibited a power conversion efficiency of 7.2% in an open-air environment without encapsulation. To be commercially viable, the environmental impact on the long-term performance and reliability of the device under harsh conditions are evaluated. The device maintains its aging stability up to 82% and photostability up to 86% relative to that in its initial test. Further, the junction quality, interface states, and recombination of charge carrier species are examined through impedance spectroscopy analysis. This study determines AgBiS2 QDs as a viable and non-toxic alternative to lead-based materials in photovoltaic applications, thus contributing to the advancement of sustainable solar technologies.