Systematic study on the impact of water on the performance and stability of perovskite solar cells

• Published in: RSC advances Vol. 6; no. 57; pp. 52448 - 52458
• Main Authors: Clegg, Charlotte, Hill, Ian G
• Format: Journal Article
• Language: English
• Published: 01.01.2016
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c6ra11379f

The effects of water on the photovoltaic performance of methylammonium lead iodide perovskite devices has recently become a topic of interest within the perovskite community. However, existing studies report contrasting and sometimes contradictory observations. In this work, small concentrations of water, consistent with those present in air-exposed DMF, were systematically incorporated directly into the PbI 2 precursor solution in order to investigate its effect on the performance of sequentially spin-coated, inverted perovskite solar cells. Increasing concentrations of water in the PbI 2 solution were found to have a negative impact on photovoltaic performance. The addition of water was observed to exaggerate the scan-rate and directional-dependent hysteresis and introduce new transient behaviours in comparison to the dry devices. Interestingly, the addition of water was also found to improve the long-term device stability in comparison with devices fabricated from dry precursors. Sequentially spin-coated inverted perovskite solar cells were constructed with systematically varied concentrations of water in the PbI 2 precursor solution. Surprisingly, small concentrations of water improved long-term stability, although with lower initial efficiency.