HalogenidPerowskite

Halogenid perovskites, commonly referred to as halide perovskites, are a class of crystalline materials with the general formula ABX3. In this structure A is a monovalent cation such as formamidinium (FA+), methylammonium (MA+), or cesium (Cs+); B is a divalent metal cation, most often lead (Pb2+); and X is a halide anion, typically chloride (Cl−), bromide (Br−), or iodide (I−). The arrangement yields a three-dimensional perovskite framework in which BX6 octahedra share corners and A cations occupy interstitial sites.

These materials are known for strong light absorption, long carrier diffusion lengths, and the ability to tune the bandgap by halide composition or cation choice. Mixed-halide and mixed-cation formulations are common to optimize optoelectronic properties.

Applications include photovoltaic cells, light-emitting diodes, photodetectors, and lasers. They can be processed from solution at relatively low temperatures, enabling low-cost fabrication.

Key challenges include environmental instability (moisture, oxygen, heat), and toxicity due to lead. Stability improvements are pursued by compositional engineering, incorporation of inorganic cations, 2D/3D hybrids, and device encapsulation. Mixed iodide/bromide compositions can suffer light-induced phase segregation, complicating long-term operation. Research also explores lead-free alternatives and more stable structural variants, though lead-based perovskites currently exhibit the best combination of efficiency and processability.

Since their emergence in the 2010s, halide perovskites have rapidly advanced in lab-scale devices, achieving high efficiencies and inspiring commercial research, though commercial deployment requires robust, scalable stability and safety solutions.