Infiltration issues in printed mesoporous carbon perovskite solar cells: a troubleshooting guide

Abstract

Printed mesoscopic carbon perovskite solar cells (CPSCs) represent a potential frontrunner to perovskite commercialisation due to their inherent stability and easily scaled fabrication methods. Devices consist of three screen printed mesoporous layers of TiO2, ZrO2 and carbon, which are subsequently infiltrated with perovskite. It is well established that complete infiltration, or filling, of the base TiO2 layer is key to achieving peak performance and reproducibility in both lab-scale devices and modules. A thorough understanding of the factors influencing infiltration is therefore essential for both lab-scale research and scale-up. TiO2 infiltration is easily examined by optical microscopy through the glass substrate. This work identifies common characteristic infiltration defects at multiple scales, caused by specific issues in the manufacturing process such as mesh marking, printing issues, contaminant damage and environmental fluctuations. Likely causes and potential solutions are presented for each type of defect, to produce a troubleshooting reference resource for tackling this problem at multiple scales. This should help enhance lab-scale reproducibility providing a simple method for quality control in future large-scale ventures.