Conjugated polymer composites as promising hole-transport materials for stable and efficient perovskite solar cells

Abstract

Perovskite solar cells (PSCs) combine high efficiency and ease of fabrication, but the main obstacles to their commercialization are related to their low operational stability. In the case of devices with n-i-p architecture the bottleneck issue is the hole transport layer (HTL) deposited atop the perovskite absorber films. Usually, it is made of heavily doped spiro-OMeTAD, which cannot provide any decent stability of PSCs. Many conjugated polymers have been evaluated as alternative HTL materials in PSCs, but their performance is usually compromised either by low hole mobility (e.g., poly(triaryalmines) such as PTA or PTAA) or by poor interface contact with the surface of passivated perovskite films (vast majority of conjugated polymers). Herein, we present a promising approach to boost the performance and stability of n-i-p PSCs by using composite HTLs. We show that composite HTL coatings enhance the stability of MAPbI₃ thin films under light exposure, and the achieved stabilization is much superior as compared to the effects provided by each of the composite components alone. Microscopy studies have revealed that composite HTLs form more uniform and compact films on the perovskite surface as compared to individual components. Due to their improved morphology, these composites exhibit good encapsulating properties and effectively block the release of gaseous photolysis byproducts from MAPbI₃, thereby enhancing perovskite thin-film stability. Furthermore, composite HTLs provide much higher photovoltaic performance as compared to the reference devices fabricated using the corresponding single-component HTLs. One composite component, which is polymer PTA, is responsible for the formation of an optimal interface with perovskite absorber films, whereas the second component facilitates charge transport to the top electrode. Thus, the observed synergistic action of two materials combined in a composite HTL film opens a new paradigm for engineering advanced n-i-p perovskite solar cells with simultaneously enhanced efficiency and stability.

Keywords

References

1. Komissarova E.A., Kuklin S.A., Latypova A.F., Nikitenko S.L., Ozerova V.V., Kevreva M.N., Emelianov N.A., Frolova L.A., Troshin P.A. Mendeleev Communications, 2024, 34(5), 656–659.
2. Komissarova E.A., Kuklin S.A., Slesarenko N.A., Latypova A.F., Akbulatov A.F., Ozerova V.V., Kevreva M.N., Emelianov N.A., Frolova L.A., Troshin P.A. Mendeleev Communications 2025, 35(3), 327–330.