Rapid improvement in the efficiency of lead halide perovskite solar cells has led to an

expansion in the interest of halide perovskite materials for optoelectronic devices. However,

concerns with toxicity and material instability pose serious challenges for the future

commercialization of lead halide perovskites solar cells. Thus, alternative materials that share

similar optoelectronic properties to lead halide perovskites are being explored. One material

that has the potential to replace lead halide perovskites is BiI3, which is nontoxic and shares a

similar electronic structure to lead halide perovskites. All-inorganic solution-processable BiI3

thin-film photovoltaic devices were developed as a proof-of-concept to demonstrate the

potential of BiI3 thin-films for photovoltaic application. Two-electron donor solvents such as

tetrahydrofuran and dimethylformamide were found to form adducts with BiI3, which made

BiI3 highly soluble in these solvents. BiI3 thin-films were deposited by spin coating. Solvent

annealing BiI3 thin films at relatively low temperatures (≤ 100 à  à °C) resulted in increased grain

size and crystallographic reorientation of grains within the films. The BiI3 films were stable

against oxidation for several months and could withstand several hours of annealing in air at

temperatures up to 150 à  à °C without degradation. Surface oxidation was found to improve

photovoltaic device performance due to the formation of a BiOI layer at the BiI3 surface

which facilitated hole extraction. BiI3 solar cells achieved highest power conversion

efficiencies of 1.0%, demonstrating the potential of BiI3 as a non-toxic, air-stable metal

halide absorber material for photovoltaic applications. This thesis serves to provide a study of

the material chemistry of BiI3, as well as opens avenues for other potential research projects

such as an extension of this work to other bismuth-based semiconductors, and the continued

development of BiI3 PV devices.