Spin coated perovskite thin films are known to poor device-to-device repeatability, mostly due to poor control on morphology of the deposited films. In this work, a post-deposition vapor annealing process was developed, which “fixes” the issues with as-deposited films, leading to high-efficiency perovskite solar cells with excellent repeatability (standard deviation of only 0.7%). The annealing process also improves the performance of the perovskite thin-films by increasing the average grain-size from 0.2 μm to 10–15 μm. The larger grain-sizes allow effective carrier recombination lifetime, as large as 54 μs, one of the highest numbers every reported. The annealed films with large-grains are also more stable in ambient conditions.
Reference:
- Arun Singh Chouhan, Naga Prathibha Jasti, Shreyash Hadke, Srinivasan Raghavan, Sushobhan Avasthi, Large grained and high charge carrier lifetime CH3NH3PbI3 thin-films: implications for perovskite solar cells, In Current Applied Physics, Volume 17, Issue 10, 2017, Pages 1335-1340, ISSN 1567-1739, https://doi.org/10.1016/j.cap.2017.07.005
- A. S. Chouhan, N. P. Jasti, S.Hadke, S. Raghavan, S. Avasthi, _Perovskite Grain Size modulation by annealing in Methyl-Amine Environment," 44th IEEE Photovoltaic Specialists Conference, Washington D. C., June 2017
- A. S. Chouhan, N. P. Jasti, R. B. Iyer, S. Avasthi, Compact-TiO2 Deposited via ALD for Highly-repeatable and Low-Hysteresis Perovskite Solar Cells," 2017 MRS Spring Meeting, Phoenix, AZ, April 2017.