Influence of transition metal substitution on Cs2AgBiBr6/M3C2 (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) interfaces: First-principles and experimental studies

Abstract

In this study, we have constructed and characterized Cs2AgBiBr6/M3C2 (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) heterostructures, utilizing a combination of density functional theory (DFT) and experimental studies. We constructed eighteen different Cs2AgBiBr6/M3C2 heterojunctions by considering the two different terminal types of Cs2AgBiBr6 as well as the nine different terminal types on the side of various early transition metal carbides. The results indicate that AgBiBr3/M3C2 heterostructures possess superior interfacial properties compared to Cs2BiBr3/M3C2 heterostructures, displaying a smaller interfacial distance, higher binding energy, and better charge transfer ability. Among the AgBiBr3/M3C2 heterostructures, AgBiBr3/Ti3C2 and AgBiBr3/Zr3C2 showed the best binding energy and charge transfer ability. Additionally, all the constructed heterostructures exhibited improved light absorption coefficient, broadened visible light absorption range, and reduced effective mass of the charge carriers. Finally, to validate the experimental synthesis feasibility of the theoretical models, we synthesized Cs2AgBiBr6/Ti3C2 composite materials, and scanning electron microscopy (SEM) images confirmed the presence of a composite structure consisting of Cs2AgBiBr6/Ti3C2. These results provide valuable theoretical guidance for developing high-performance Cs2AgBiBr6/M3C2 heterostructures in optoelectronic perovskite devices.