Inkjet-Printed Electron Transport Layers for Perovskite Solar Cells

Inkjet printing emerged as an alternative deposition method to spin coating in the field of perovskite solar cells (PSCs) with the potential of scalable, low-cost, and no-waste manufacturing. In this study, the materials TiO(2), SrTiO(3), and SnO(2) were inkjet-printed as electron transport layers (ETLs), and the PSC performance based on these ETLs was optimized by adjusting the ink preparation methods and printing processes. For the mesoporous ETLs inkjet-printed from TiO(2) and SrTiO(3) nanoparticle inks, the selection of solvents for dispersing nanoparticles was found to be important and a cosolvent system is beneficial for the film formation. Meanwhile, to overcome the low current density and severe hysteresis in SrTiO(3)-based devices, mixed mesoporous SrTiO(3)/TiO(2) ETLs were also investigated. In addition, inkjet-printed SnO(2) thin films were fabricated by using a cosolvent system and the effect of the SnO(2) ink concentrations on the device performance was investigated. In comparison with PSCs based on TiO(2) and SrTiO(3) ETLs, the SnO(2)-based devices offer an optimal power conversion efficiency (PCE) of 17.37% in combination with a low hysteresis. This work expands the range of suitable ETL materials for inkjet-printed PSCs and promotes the commercial applications of inkjet printing techniques in PSC manufacturing.