Light-induced lattice expansion leads to high-efficiency perovskite solar cells
We report that continuous light illumination leads to a uniform lattice expansion in hybrid perovskite thin films, which is critical for obtaining high-efficiency photovoltaic devices. Correlated, in situ structural and device characterizations reveal that light-induced lattice expansion benefits the performances of a mixed-cation pure-halide planar device, boosting the power conversion efficiency from 18.5 to 20.5%. The lattice expansion leads to the relaxation of local lattice strain, which lowers the energetic barriers at the perovskite-contact interfaces, thus improving the open circuit voltage and fill factor. The light-induced lattice expansion did not compromise the stability of these high-efficiency photovoltaic devices under continuous operation at full-spectrum 1-sun (100 milliwatts per square centimeter) illumination for more than 1500 hours.
Source: ScienceNOW - Category: Science Authors: Tsai, H., Asadpour, R., Blancon, J.-C., Stoumpos, C. C., Durand, O., Strzalka, J. W., Chen, B., Verduzco, R., Ajayan, P. M., Tretiak, S., Even, J., Alam, M. A., Kanatzidis, M. G., Nie, W., Mohite, A. D. Tags: Physics, Applied, Materials Science reports Source Type: news