Prof. Zhen Li group (School of Materials Science and Engineering, NPU), in collaboration with Prof. Chao Zhang (School of Aeronautics, NPU) recently published a paper entitled “Annealing Free Tin Oxide Electron Transport Layers for Flexible Perovskite Solar Cells” in Nano Energy (2022, 94, 106919). In this paper, they proposed a facile amine gas fuming strategy to prepare SnO₂ compact layer, which totally avoided thermal annealing. The process was illustrated in Figure 1. With methylamine gas treatment, the OH- groups on the surface of the SnO₂ particles are deprotonated to form Sn-O⁻ bond, which leads to particle-to-particle connection and densification of the film.

Amine gas fuming for annealing free deposition of SnO₂ film

Electron transport layer (ETL) is a key component in the perovskite solar cells (PSCs). Low temperature, even room temperature deposition technique for ETLs is especially intriguing for flexible solar cell fabrication on polymer substrates. In this work, they proposed an annealing free deposition method to circumvents thermal stress and degradation issues caused by thermal annealing. Amine treatment promotes the crosslinking of the SnO2 colloidal and significantly improves the mechanical and adhesion strengths of the film. The annealing free strategy for preparing compact oxide layer opens a new avenue for the fabrication of flexible solar cell and wearable electronics towards practical applications. The main novelties of present work are as following:

1. This work proposes a base-catalyzed densification mechanism to promote the SnO2 colloidal converted into compact film through particle connections and attachments facilitated by basic amine gas treatments.

2. The flexible PSCs with amine treated SnO2 yield PCE of up to 19.80%, maintaining 94.5% of the initial PCE after 3000 bending cycles with a bending radius of 2.5 mm.

Prof. Zhen Li group in School of Materials Science and Engineering, Northwestern Polytechnical University, has been working on the perovskite solar cells and their flexible applications. Prof. Chao Zhang group in School of Aeronautics, Northwestern Polytechnical University, has been working on the mechanics of composites and energy devices. In this work, Prof. Zhen Li and Prof. Chao Zhang are the corresponding authors, Zhihao Li is the first authors.

The article link is as follows: https://doi.org/10.1016/j.nanoen.2022.106919

Author: Zhen Li

Reviewer: Hongqiang Wang，Wei  Liu