Antisolvent Treatment on Wet Solution‐Processed CuSCN Hole Transport Layer Enables Efficient and Stable Perovskite Solar Cells

Abstract

Among the various inorganic hole‐transporting materials for perovskite solar cells (PSCs), CuSCN is identified as a promising candidate for commercialization applications owing to its abundance and solution processability with alkyl sulfides. Although CuSCN possesses high intrinsic thermal stability, the existence of diethyl sulfide (DES) residue during the wet processing of CuSCN films accelerates perovskite degradation, impeding the practical application of CuSCN in PSC applications. This study demonstrates a new antisolvent‐treatment strategy to extract DES residue from CuSCN. The antisolvent treatment with the aid of diethyl ether (DEE) successfully results in a dense and high‐quality CuSCN film with improved surface morphology, trap density, and hole extraction ability. Consequently, the power conversion efficiency of DEE‐treated CuSCN‐based PSCs improves from 16.84% to 18.34% with superior long‐term stability. This study provides a simple method for the preparation of high‐quality CuSCN films that can effectively be applied to the large‐area fabrication of CuSCN‐based PSCs.

Recent Progress of Inorganic Hole‐Transport Materials for Perovskite Solar Cells†

“…[ 68 ] Recently, Wei and coworkers proposed an antisolvent‐treatment approach for the DES‐processed CuSCN to mitigate solvent residue induced degradation of perovskite. [ 71 ] Antisolvent‐treatment is a facile and effective method for preparing high‐quality CuSCN films, which can delicately adjust the perovskite film morphology. The chemical reaction between CuSCN film and electrode was often observed.…”

Realizing Efficient and Stable n-i-p Perovskite Solar Cells with CuSCN Hole Transporting Materials via LiSCN Doping and Interface Modulation

“…Moreover, introducing oxide graphene as the space layer can further boost the device's durability. Even so, the relatively inferior efficiency of CuSCN-based PSCs greatly limited its development, which can be mainly attributed to two factors: (i) the interface issue caused by the damage of the diethyl sulfide (DES) solvent of CuSCN on perovskite; 22,23 (ii) the inferior conductivity of pristine CuSCN prepared from a sulfide-based solvent. 24 An interface modifier on the perovskite surface is commonly adopted to mitigate the damage from the DES solvent.…”

Bidirectional Passivation for Highly Efficient and Stable CuSCN-Based Perovskite Solar Cells Using (3-Mercaptopropyl)trimethoxysilane

“…16−18 Apart from the DES-induced damage of the PVSK layer, the aging of the bare PVSK/CuSCN interface caused the formation of the defective Pb 0 and CuI at the interface and thereby lowered the open-circuit voltage (V OC ) of the device. 14,18,19 Several methods have been investigated to solve or mitigate the DES-induced damage of the PVSK layer, including the use of antisolvent treatment for the fast removal of DES from the wet CuSCN film 13 or insertion of an interlayer between the PVSK and CuSCN layer using PDMS, 20 PMMA, 19 and polyethylene glycol (PEG). 21 More recently, Madhavan et al attempted to passivate the defects across the PVSK/CuSCN interface by inserting an ultrathin 2D perovskite compound on the surface of the PVSK absorber.…”