TBSI researchers develop efficient perovskite solar cells through green anti-solvent engineering

A team of researchers from Tsinghua-Berkeley Shenzhen Institute (TBSI) and Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences, have developed more efficient perovskite solar cells using green anti-solvents. 

Perovskites are often used in solar cells as they exhibit superior optoelectronic properties, but traditional one-step solution-processed perovskites often suffer from defects-induced non-radiative recombination, which significantly hinders the improvement of device performance. Anti-solvent engineering has been demonstrated to be effective in tuning crystal nucleation and grain growth. However, large amounts of anti-solvents are required for achieving high efficiency and more importantly, most of these anti-solvents such as chlorobenzene and toluene are toxic. In this regard, the development of toxicity-free green anti-solvent engineering for high performance perovskite solar cells (PSCs) is very attractive.

TBSI Assistant Prof. Guodan Wei and Prof. Feiyu Kang’s group collaborated with SIAT Prof. Jiangyu Li, and recently published their research titled “Suppressing Defects-Induced Non-Radiative Recombination for Efficient Perovskite Solar Cells through Green Anti-Solvent Engineering” in Advanced Materials.

Researchers chose the green anti-solvent methylamine bromide (MABr) in ethanol (MABr-Eth) to modify perovskite films. The MABr treatment not only enhanced the resultant perovskite crystallinity with large grain size, but also passivated surface defects. MABr-Eth-treated perovskite films showed improved crystallinity and morphology with higher coverage, longer charge carrier decay time, and a lower density of surface defect states. Additionally, this strategy delivered PSCs with the best power conversion efficiency  of 21.53%, as well as better storage and light-soaking stability.

These results confirmed that the MABr-Eth treatment can substantially suppress defects-induced non-radiative recombination for PSCs, and also signified the importance of rationally choosing green anti-solvents for PSCs to achieve improved performance and stability.

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Fig.1 c-AFM images of perovskite thin films measured in dark and under illumination


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Fig. 2 Femtosecond transient absorption spectra of perovskite thin films and possible exciton capture and recombination processes



Link to full article:https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202003965

 

 





Writer: Xu Wenzhan

Editor: Karen Lee