CiteWeb id: 20130000104

CiteWeb score: 1505

DOI: 10.1126/science.1243167

Low temperature solution processed photovoltaics suffer from low efficiencies due to poor exciton/electron-hole diffusion lengths (ty pically about 10 nanometers). Recent reports of highly efficient CH3NH3PbI3-based solar cells in a broad range of configuratio ns raise a compelling case for understanding the funda mental photophysical mechanisms in these materials. By applying femtosecond transient optical spectroscopy to bilayers that interface this perovskite with either selective ele ctron or selective hole extraction materials, we have uncovered concrete evidence of balanced lon g-range electron-hole diffusion lengths of at least 100 nm in solution processed CH3NH3PbI3. The high photoconversion efficiencies of these systems stem from the comparable optical a bsorption length and charge carrier diffusion lengths, transcending the traditional con straints of solution processed semiconductors.