Science 338, 643–647 (2012)

Credit: © 2012 AAAS

Dye-sensitized solar cells show some of the highest power-conversion efficiencies of all solution-processable photovoltaic devices, but the use of liquid electrolytes can limit their long-term stability. Recent research has hence explored the replacement of the liquid electrolyte by a polymeric hole conductor and the sensitization of the mesoporous TiO2 electrode with a thin inorganic semiconducting absorber layer. Henry Snaith and colleagues now report an improved architecture for such hybrid solar cells that leads to efficiencies of up to 10.9%. The key component is the perovskite CH3NH3PbI2Cl, which is stable in air and suitable for solution processing. The compound is deposited onto mesoporous insulating Al2O3 instead of TiO2, which leads to an enhanced open-circuit voltage and high internal photoconversion efficiency across wide parts of the visible solar spectrum. The researchers attribute this enhancement to charge transport through the perovskite coating and suggest that increased absorption in the infrared range could further improve the performance of such hybrid solar cells.