Publication date: 21st July 2025
Perovskite solar cells have attracted substantial attention due to their promising efficiency, but their operational stability, particularly at the interfaces with charge transport layers, remains a key limitation. This issue is especially critical in inverted (p-i-n) architectures, where fullerene-based electron transport layers often compromise long-term device stability. In response, the use of low-dimensional perovskite interlayers with hydrophobic organic spacers was explored to improve stability by templating the perovskite structure. [1] However, conventional organic cations used in these interlayers are typically electronically inert, which hampers charge extraction and reduces overall device efficiency. In this work, we introduce low-dimensional perovskites incorporating electroactive napthalimide- and napthalenediimide-based spacers.[2,3] These functional organic moieties also enable modification or replacement of the fullerene-based electron transport layers, producing passivated interfaces that support efficient charge transport. This strategy led to improved photovoltaic performance, achieving power conversion efficiencies exceeding 20% along with enhanced device stability, underlining the value of electroactive interlayers in optimizing inverted perovskite solar cells.