Refining the Substrate Surface Morphology for Achieving Efficient Inverted Perovskite Solar Cells

Significant advancements in perovskite solar cells (PSCs) have been driven by the engineering of the interface between perovskite absorbers and charge transport layers. Inverted PSCs offer substantial potential with their high power conversion efficiency (PCE) and enhanced compatibility for tandem solar cell applications. Conventional hole transport materials like poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(triaryl amine) (PTAA) not only constrain the PSC efficiency but also elevate their fabrication costs. In the case of improving inverted structured PSCs according to the aforementioned concerns, utilizing self-assembled monolayers (SAMs) as hole-transporting layers has played a crucial role. However, the growth of self-assembled monolayers on the substrates still limits the performance and reproducibility of inverted structured PSCs. In this study, the authors delve into the growth model of SAMs on different surface morphologies. Moreover, it is found that the plasma treatment can effectively regulate the surface morphologies of substrates and achieve conformal growth of SAMs. This treatment improves the uniformity and suppresses non-radiative recombination at the interface, which leads to a PCE of 24.5% (stabilized at 23.5%) for inverted structured PSCs. In perovskite solar cells (PSCs), engineering the interface between perovskite absorber thin films and charge transport layers has been pivotal. Self-assembled monolayers (SAMs) in the electron-blocking layer have improved contact efficiency, reducing interfacial recombination. SAM growth models and plasma treatment for conformal SAM growth are investigated, suppressing non-radiative recombination. This approach achieves 24.5% power conversion efficiency (stabilized at 23.5%) in inverted PSCs.image