Work

Excellent Intrinsic Thermally Stable Coevaporated LiF:C 60 Layers Mitigate Interface Defects and Charge Losses in Fully Vacuum‐Processed Perovskite Solar Cells

Year: 2026

Type: article

Abstract: Despite being one of the most promising candidates for emerging market opportunities, all‐vacuum‐deposited perovskite solar cells (PSCs) still suffer from significant efficiency limitations, primarily due to open‐circuit voltage ( V OC ) losses caused by interfacial defects at the top surface of the perovskite layer. In this work, we demonstrate PSCs fabricated via a simple, sandwich‐type all‐vacuum thermal evaporation process, incorporating an ultrathin (6 nm) MS‐OC (spiro[fluorene‐9,9′‐phenanthrene‐10′‐one] incorporated with o ‐phenylcarbazole) hole transport layer (HTL) as a growth template for hybrid metal–halide perovskites. To mitigate V OC losses and better understand the interfacial charge dynamics, we systematically investigate various electron transport materials (ETMs), with a particular focus on C 60 , LiF, and coevaporated C 60 :LiF (1:1). Our results reveal that the C 60 :LiF (1:1) coevaporation strategy not only suppresses fullerene aggregation but also effectively passivates the perovskite surface, thereby reducing nonradiative recombination and enhancing V OC by 23.37%. As a result, the power conversion efficiency (PCE) of the PSCs improved by 29.34%, reaching a PCE of 13.4% with low nonradiative loss (~135 mV). More importantly, this composite passivation approach significantly enhanced the device's environmental stability, maintaining 90% of its initial efficiency after 600 h of operation.

Source: Solar RRL

DOI: 10.1002/solr.202500602