Perovskite solar cells (PSCs) have received great attention due to their high power conversion efficiency and low fabrication cost. The perovskite layer is usually prepared from a solution of precursors. We found that the PbI2 purity has a significant effect on the crystallinity, charge carrier dynamics, and photovoltaic properties of the perovskite films. Planar heterojunction PSCs using highly pure PbI2 showed a high power conversion efficiency (PCE) of 16.4%, which was higher than that of control PSCs with low purity PbI2 by 30-40%. Steady-state photoluminescence (PL), time-resolved PL (TR-PL) and femtosecond transient absorption measurements (FS-TA) revealed that impurities can lower the electron lifetime and increase the non-radiative recombination. This study implies that the PCEs of the perovskite solar cell devices could be further boosted by controlling the precursor purity.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)