Intense Pulsed Light Annealing of Tin(IV) Oxide Electron-Transport Layer for Large-Scale Fabrication of Flexible Printed Perovskite Solar Cells

Abstract

Intense pulsed light (IPL) annealing is a rapid heat treatment technique that significantly reduces the fabrication time of flexible printed perovskite solar cells (FPPSCs) and is compatible with roll-to-roll (R2R) systems. This work presents the results of the optimization of IPL annealing for the tin(IV) oxide (SnO₂) electron-transport layer (ETL) and systematically compares IPL-annealed samples with their hot plate-annealed counterparts, designated as REF-SnO₂. Thin-film characterization reveals that the optimal condition, referred to as IPL-SnO₂, involves a two-step annealing process: hot plate drying at 100°C for 5 min followed by a single flash with a pulse voltage of 2400 V and a pulse duration of 1000 μs. Notably, IPL-SnO₂ and REF-SnO₂ films exhibit nearly identical electrical, optical, and morphological properties. Moreover, devices fabricated with IPL-SnO₂ and REF-SnO₂ ETLs demonstrate comparable photovoltaic performance, reaching average power conversion efficiencies (PCEs) of 8.92% and 8.94%, respectively. Photostability tests show that IPL-SnO₂ devices are operational after 4500 min of continuous illumination. To distinguish the immediate effect of IPL annealing from that of preannealing, characterizations are conducted in parallel on nonannealed and preannealed samples, termed WA-SnO₂ and PRE-SnO₂, respectively. These findings confirm that IPL annealing is a promising approach for scaling up FPPSCs.