First-principles investigation of next-generation lead-free InXCl3 halide perovskites

The ABX3-type single perovskite-based compound has become one of the most beneficial sets of materials in terms of future optoelectronic applications. First-principles calculations based on the density functional theory in this work resulted in the discovery of an indium-based family (InXCl3, X = Cd, Cu, Hg, Ni, Pd, and Zn) of next-generation technologies. These compounds are thermodynamically stable, and their formation enthalpies lie between −2.36 and −3.59 eV/atom. Electronic analysis shows that the materials are metallic-semiconducting with a range of band structures between 0.934 and 1.835 eV and with an indirect bandgap that enables them to effectively use the solar spectrum. The mechanical measurement illustrates a wide range of behavior, from ductile and flexible all the way up to ultra-stiff and brittle, which is directly a result of the bonds' character. A sharp ductile–brittle boundary appears at the critical Pugh ratio (B/G). The only brittle constituents in any one of the compositions are InNiCl3 and InPdCl3 with 10.73 and InHgCl3 with 3.38, and other compounds are highly ductile. These materials exhibit high electrical conductivity and ultraviolet reflectivity, thus presenting new possibilities in the development of photodetectors and plasmonic devices due to their high absorption and conductivity. Lattice thermal conductivities of materials are diverse and have been used for both thermal insulation and heat-spreading purposes. The integrated stability, adjustability, and versatility of InXCl3 perovskites make them a preferable material that will be usable in the field of photovoltaic technology, flexible electronics, optical coating, and heat management in future applications.