Self‐Assembled Monolayer Dyes for Contact‐Passivated and Stable Perovskite Solar Cells

Abstract

AbstractSurface modification of transparent conductive oxides (TCOs) with carbazole‐based self‐assembled monolayers (SAMs) is an effective method toward the formation of highly efficient hole‐selective contacts, enabling the fabrication of high‐performance perovskite solar cells (PSCs). However, the lack of long‐term structural and performance stability of the TCO/SAM/perovskite stack endangers the market entry of PSCs. Here, it is demonstrated that these challenges can be overcome by employing dyes as multi‐functional SAMs, simultaneously facilitating charge transport, passivating interfacial defects, and acting as a “molecular adhesive” layer, preserving structural integrity of the contact stack. Particularly, the surface modification of ITO with a dye (N719) monolayer is shown to create a hole‐selective contact for the fabrication of p–i–n PSCs with power conversion efficiencies reaching 24%. The N719 SAM‐based PSCs have also shown superior stability compared to state‐of‐the‐art PSCs incorporating carbazole SAMs and polyarylamine hole‐selective contacts by preserving ≈90% of their initial PCE under continuous light and thermal stress tests for 1000 h. The robustness of the ITO/N719/perovskite stack is attributed to its low interfacial trap density, UV resilience and strong adhesion capability. These findings place dye SAMs as a promising alternative for improving the performance of next‐generation photovoltaics.