All‐Printed Roll‐to‐Roll Perovskite Photovoltaics Enabled by Solution‐Processed Carbon Electrode

TLDR

Perovskite photovoltaics promise high efficiency and scalable solution processing, yet fully roll‑to‑roll fabrication has been limited by the absence of a compatible solution‑processable back electrode, forcing the use of expensive evaporated metal contacts. This study aims to develop a fully roll‑to‑roll printable perovskite device by integrating a low‑temperature n‑i‑p architecture with R2R‑compatible solution formulations to eliminate interlayer incompatibilities and recombination losses. The device employs an n‑i‑p stack of SnO₂/perovskite/PEDOT:PSS/carbon, where the carbon electrode provides an ohmic contact to the p‑type layer, enabling solution processing. The resulting devices achieve 13–14 % efficiency on small scale, matching evaporated gold contacts, and the fully roll‑to‑roll prototype delivers a stabilized 10.8 % power‑conversion efficiency while retaining 84 % of its initial performance after 1,000 h at 70 % RH and 25 °C.

Abstract

Perovskite photovoltaics have shown great promise in device efficiency but also the promise of scalability through solution-processed manufacture. Efforts to scale perovskites have been taken through printable mesoporous scaffolds and slot die coating of flexible substrates roll-to-roll (R2R). However, to date there has been no demonstration of entirely R2R-coated devices due to the lack of a compatible solution-processable back electrode; instead, high-value evaporated metal contacts are employed as a post process. Here, in this study, the combination of a low-temperature device structure and R2R-compatible solution formulations is employed to make a fully R2R printable device architecture overcoming interlayer incompatibilities and recombination losses. Therefore, the n-i-p device structure of SnO2 /perovskite/poly(3,4-ethylenedioxythiophene)/carbon is employed to form an ohmic contact between a p-type semiconductor and printable carbon electrode. In particular, the results show that the small-scale device efficiencies of 13-14% are achieved, matching the device performance of evaporated gold electrodes. Also, this entirely R2R-coated perovskite prototype represents a game changer, reaching over 10% (10.8) stabilized power conversion efficiency with unencapsulated long-term stability retaining 84% of its original efficiency over 1000 h under 70% RH and 25 °C.