Supramolecular Modulation for Hybrid Perovskite Photovoltaics

Hybrid perovskites are emerging as top contenders in the next generation of photovoltaics, yet their stability under operational conditions remains a significant challenge. Specifically, degradation occurs at the interface with charge transport layers in perovskite solar cells during operation.[1] To address this, we explore using supramolecular interfacial modulators at the interface of charge-transport layers with the purpose of suppressing degradation without interfering with the photovoltaic performance.[2,3] This included functionalised triarylamine-based modulators, which are known to form hole-transporting supramolecular stacks,[2] as well as chiral P,M-(1-methylene-3-methyl-imidazolium)[6]helicene iodides, which could contribute to the charge transport through chiral-induced spin-selectivity (CISS) effects. These modulators were applied at the interface between the perovskite active layer and the hole-transporting material in conventional perovskite solar cells (Figure 1). We have investigated their impact on the structural characteristics and optoelectronic properties via a combination of techniques, including X-ray diffraction, UV-vis and both steady-state and time-resolved photoluminescence spectroscopy, complemented with the further analysis of photovoltaic devices. Our investigation challenges the role of chirality in perovskite photovoltaics and reveals the contribution to the improvement of operational stabilities without compromising device performance, offering promising new strategies for advancing perovskite photovoltaics.