An in situ bifacial passivation strategy for flexible perovskite solar module with mechanical robustness by roll-to-roll fabrication?

Journal of Materials Chemistry A Pub Date: 2021-01-26 DOI: 10.1039/D0TA12067G

Abstract

The inevitable interfacial defects in the under layer of perovskite films still hinder the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs), especially of large-area flexible devices up-scaled by roll-to-roll (R2R) technology. Herein, we demonstrate an in situ bifacial passivation strategy via a simple hydroiodic acid (HI) soaking of NiOx-based hole transport layer during R2R printing. Concretely, the trivalent nickel compound on the film surface is reduced to nickel iodide (NiI2) by a HI redox reaction, thereby optimizing the interface contact and ameliorating the work function. Meanwhile, NiI2 coordinates with lead atoms in the perovskite to form a Pb–I bond, which induces the orderly growth of the perovskite lattice and enhances the quality of the crystalline film. Consequently, the PCE of the optimized flexible devices reaches up to 19.04% (1 cm2) and 16.15% (15 cm2). Moreover, the stability and mechanical property of these devices are also improved. This work provides a deep understanding of the NiOx/perovskite interface and an approach for printable interface optimization.

Graphical abstract: An in situ bifacial passivation strategy for flexible perovskite solar module with mechanical robustness by roll-to-roll fabrication
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