AgBiS2 as a photoabsorber for eco-friendly solar cells: a review

The search for non-toxic and non-heavy metal absorbers for use is solar cells is attracting a lot of attention, and this research has led to the development of many non-toxic nanocrystal absorbers that have the capability to be integrated into cost-efficient, stable, and environmentally friendly solar cells. The ternary chalcogenide AgBiS2 exhibits unique properties, such as having a tunable bandgap, high absorption coefficient, and environmental stability, together with easy processability, and it has attracted the attention of the research community over the last few years. Although theoretical studies exposit a power conversion efficiency (PCE) of 26% for these emerging nanocrystals, experimentally they have not been able to go beyond 9%, which has motivated researchers to explore these ternary chalcogenides. This review provides a detailed understanding of the intrinsic properties of AgBiS2, such as its structural, optical, and electronic band properties, and the device engineering strategies applied so far. The role and influence of various charge transport layers surrounding this absorber on device performance are also described and discussed scientifically. Finally, our conclusions and perspectives provide real insights into choosing appropriate techniques, methods, and charge transport materials to achieve and maximize the performance and power conversion efficiencies of these promising AgBiS2 devices.