Organic-inorganic lead halide perovskite solar cell materials: A possible stability problem

- Methyl ammonium lead halides are visible-light absorbers and novel solar cell materials.
- These perovskite-structured materials are sensitive to humidity and oxygen.
- Their lead halide parts may exhibit photodecomposition, like the binary lead halides.
- The mechanism of the photodecomposition of binary lead halides is presented in detail.
- It is necessary to study the formation of monovalent lead ions under irradiation.