Toward a Scalable Fabrication of Perovskite Solar Cells under Fully Ambient Air Atmosphere: From Spin-Coating to Inkjet-Printing of Perovskite Absorbent Layer

Up until now, the vast majority of perovskite solar cells (PSCs) have relied on the spin-coating of perovskite precursor solution under inert fully controlled conditions, with the performance of solar cells that are developed by alternative techniques and under an ambient atmosphere to lag far behind. This impedes the technology transfer from the laboratory to industrial large-scale production; thus, the investigation of new scalable techniques should be thoroughly considered. The present work constitutes one of the few investigations on the application of inkjet-printing as an advanced alternative technique to the conventional spin-coating technique used for the fabrication of fully ambient air-processed perovskite absorbent layers for carbon-based hole transport layer-free PSCs. A systematic study of the characteristics of the perovskite material and solar cells indicated that the coffee-ring effect combined with poor ink penetration into the mesoporous network of the anode semiconductor were the main reasons for obtaining poor perovskite structure morphology and lower PSC performance by inkjet-printing, which arises from a lower internal quantum efficiency and an increased charge transfer and recombination rate. On the other hand, the crystallinity and optical characteristics of the materials obtained by the compared techniques did not differ considerably, while small differences were observed in the hysteretic behavior and long-term stability of the solar cells.