Tl3PbI5 Nanocrystals for Ultraviolet Photovoltaics.

Tl₃PbI₅ exhibits a bandgap energy suitable for absorbing visible and ultraviolet spectra along with a high absorption capability, rendering it a promising candidate for a broader range of solar energy applications. However, its applicability as a light absorber in solar cells is yet to be experimentally confirmed. In this study, we systemically investigate the synthesis process and the crystallographic and chemical properties of Tl₃PbI₅ nanocrystals. These results enable the optimization of Tl₃PbI₅ nanocrystals for use as a light absorber. In addition, a solid-state ligand exchange method employing methyl acetate (MeOAc) is introduced to construct a Tl₃PbI₅ absorption layer for photovoltaic applications. This method facilitates the preparation of multilayer thin films with precise thickness control. The optimally designed Tl₃PbI₅-based solar cell achieves a power conversion efficiency (PCE) of 0.20%. Furthermore, the device retains over 90% of its PCE after 2000 h at 25 °C and 60% relative humidity, indicating the potential of Tl₃PbI₅-based photovoltaics for reliable solar energy harvesting. [ABSTRACT FROM AUTHOR]