text: Synthetic perovskites are possible materials for high-efficiency photovoltaics – they showed a conversion efficiency of up to 26.3% and can be manufactured using the same thin-film manufacturing techniques as that used for thin film silicon solar cells. Methylammonium tin halides and methylammonium lead halides are of interest for use in dye-sensitized solar cells. Some perovskite PV cells reach a theoretical peak efficiency of 31%.
  Among the methylammonium halides studied so far the most common is the methylammonium lead triiodide (). It has a high charge carrier mobility and charge carrier lifetime that allow light-generated electrons and holes to move far enough to be extracted as current, instead of losing their energy as heat within the cell.  effective diffusion lengths are some 100 nm for both electrons and holes.
  Methylammonium halides are deposited by low-temperature solution methods (typically spin-coating). Other low-temperature (below 100 °C) solution-processed films tend to have considerably smaller diffusion lengths. Stranks et al. described nanostructured cells using a mixed methylammonium lead halide () and demonstrated one amorphous thin-film solar cell with an 11.4% conversion efficiency, and another that reached 15.4% using vacuum evaporation. The film thickness of about 500 to 600 nm implies that the electron and hole diffusion lengths were at least of this order. They measured values of the diffusion length exceeding 1 μm for the mixed perovskite, an order of magnitude greater than the 100 nm for the pure iodide. They also showed that carrier lifetimes in the mixed perovskite are longer than in the pure iodide. Liu et al. applied Scanning Photo-current Microscopy to show that the electron diffusion length in mixed halide perovskite along (110) plane is in the order of 10 μm.
  For , open-circuit voltage (V) typically approaches 1 V, while for  with low Cl content, V > 1.1 V has been reported. Because the band gaps (E) of both are 1.55 eV, V-to-E ratios are higher than usually observed for similar third-generation cells. With wider bandgap perovskites, V up to 1.3 V has been demonstrated.
  The technique offers the potential of low cost because of the low temperature solution methods and the absence of rare elements. Cell durability is currently insufficient for commercial use. However, the solar cells are prone to degradation due to volatility of the organic [CHNH]I salt. The all-inorganic perovskite cesium lead iodide perovskite (CsPbI) circumvents this problem, but is itself phase-unstable, the low temperature solution methods of which have only been recently developed.
  Planar heterojunction perovskite solar cells can be manufactured in simplified device architectures (without complex nanostructures) using only vapor deposition. This technique produces 15% solar-to-electrical power conversion as measured under simulated full sunlight.