Tl3PbI5 Nanocrystals for Ultraviolet Photovoltaics

Abstract

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 degrees C and 60% relative humidity, indicating the potential of Tl3PbI5-based photovoltaics for reliable solar energy harvesting.