Sputtered NiO interlayer for improved SAM coverage and pin‐hole free perovskite coating for scalable NIR‐transparent perovskite and 4‐terminal all‐thin‐film tandem modules

The use of carbazole‐based self‐assembled monolayer (SAM) as a hole transport layer (HTL) has led to the efficiency advancement in p‐i‐n perovskite solar cells (PSCs). However, PSCs with SAM HTL display a large spread in device performance even on small‐area substrates owing to poor SAM surface coverage and dewetting of the perovskite ink. Efforts to improve the uniformity in device performance of SAM‐based PSCs have been confined to spin‐coating method, which lacks high‐throughput capabilities and leads to excessive material wastage. In this work, we utilize a scalable bi‐layer HTL stack with sputtered NiO and blade‐coated SAM to achieve improved SAM coverage and accomplish uniform coating of perovskite absorber on 5 cm × 5 cm substrates. We achieve fully scalable p‐i‐n PSCs with efficiency close to 19% with minimal spread in device performance. To showcase the upscaling potential, near‐infrared‐transparent perovskite mini‐modules with efficiency close to 15% and 13% were achieved on an aperture area of 2.56 cm 2 and 12.96 cm 2 . Together with low‐bandgap (1.0 to 1.1 eV) Cu(In,Ga)Se 2 (CIGS) mini‐modules, we demonstrate the first fully scalable 4‐terminal perovskite‐CIGS tandem mini‐module with an efficiency of 20.5% and 16.9% on an aperture area of 2.03 cm 2 and 10.23 cm 2 . This article is protected by copyright. All rights reserved.