Large area bar coated TiO2 electron transport layers for perovskite solar cells with excellent performance homogeneity

Perovskite solar cells (PSCs) are the potential futuristic renewable energy technologies for solar energy con-version with their rapid rise in efficiencies. Towards realizing large scale PSCs, this work presents an economic, sustainable and scalable bar coating with high throughput for electron transport layers (ETL) on 50 mm x 50 mm substrates. Bar coating is systematically engineered to obtain conformally covered compact TiO2 on FTO glass followed by mesoporous layer of desired thickness. For a fair evaluation, spin coated TiO2 on similar size sub-strates are compared. Optical and photoluminescence analyses unveil greater homogeneity of bar coated ETL over spin coated counterparts. PSCs on bar coated ETL exhibit comparable efficiencies with good reproducibility and reduced hysteresis compared to conventional spin coated ETL devices. Photovoltaic performance homoge-neity on larger substrates is significantly higher for bar coated ETL devices than the spin coated ones. The study provides scalable, sustainable and appropriately engineered bar coating technique for TiO2 on larger substrates, which are demonstrated in high performance PSCs thereby indicating the practical implications towards the fabrication of perovskite solar modules.

Automated summary

This study presents an economic, sustainable and scalable bar coating technique for the electron transport layer (ETL) of perovskite solar cells (PSCs). The bar coated ETL devices exhibit higher homogeneity and better performance stability compared to conventional spin coated ETL devices.