A thermotropic liquid crystal enables efficient and stable perovskite solar modules
Perovskite solar cells have seen impressive progress in performance and stability, yet maintaining efficiency while scaling area remains a challenge. Here we find that additives commonly used to passivate large-area perovskite films often co-precipitate during perovskite crystallization and aggregate at interfaces, contributing to defects and to spatial inhomogeneity. We develop design criteria for additives to prevent their evaporative precipitation and enable uniform passivation of defects. We explored liquid crystals with melting point below the perovskite processing temperature, functionalization for defect passivation and hydrophobicity to improve device stability. We find that thermotropic liquid crystals such as 3,4,5-trifluoro-4 '-(trans-4-propylcyclohexyl)biphenyl enable large-area perovskite films that are uniform, low in defects and stable against environmental stress factors. We demonstrate modules with a certified stabilized efficiency of 21.1% at an aperture area of 31 cm2 and enhanced stability under damp-heat conditions (ISOS-D-3, 85% relative humidity, 85 degrees C) with T86 (the duration for the efficiency to decay to 86% of the initial value) of 1,200 h, and reverse bias with (ISOS-V-1, negative maximum-power-point voltage) and without bypass diodes.|Retaining high performance of perovskite solar cells over large areas is a challenge. Yang et al. use a thermotropic liquid crystal with high diffusivity that does not co-crystallize with the perovskite, suppressing defect formation and enabling large-area solar modules with improved stability and efficiency.
WOS:001144459800001
2024-01-18
REVIEWED
Funder | Grant Number |
United States Department of Defense | United States Navy | Office of Naval Research (ONR) | N00014-20-1-2725 |
ONR | |
US Department of Commerce, National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design | |
NUFAB facilities of Northwestern University | ECCS-2025633 |
SHyNE Resource (National Science Foundation (NSF)) | DMR-2308691 |
NSF | ECCS-2025633 |
SHyNE Resource (NSF) | DMR-1720319 |
NSF MRSEC at Northwestern University | |
Canada Foundation for Innovation | |
Natural Sciences and Engineering Research Council | |
National Research Council | |
Canadian Institutes of Health Research | |
Government of Saskatchewan | |
University of Saskatchewan | |
King Abdullah University of Science and Technology through the Ibn Rushd Postdoctoral Fellowship Award | |