Pseudohalides in Lead-Based Perovskite Semiconductors

The emerging class of lead halide perovskite (LHP) semiconductors offers a surprising combination of low cost, ease of preparation, outstanding material properties, and performance in optoelectronic devices that has not yet been observed in any other class of material. Considering their general ABX ₃ formula, the halide (X) composition in LHP compositions has proven to be one of the best handles to control the material characteristics such as bandgap, morphology, and electronic properties. However, compared to the amount of effort that has been expended to discover new A cations and B cations, relatively few reports have dealt with the subject of discovering new X anions outside of the series of halides (Cl ⁻ , Br ⁻ , I ⁻ ). In principal, a much wider range of anions with a −1 charge (pseudohalides) may form the ABX ₃ stoichiometry with Pb ²⁺ , yet the general ability of polyatomic pseudohalides to form semiconducting perovskite crystal phases with Pb ²⁺ remains an open question. Herein, the prospect of using polyatomic pseudohalide anions in LHP semiconductors is addressed.