Role of Polycyclic Aromatic Alkylammonium Cations in Tuning the Electronic Properties and Band Alignment of Two-Dimensional Hybrid Perovskite Semiconductors

Two-dimensional hybrid organic-inorganic perovskites (HOIPs) have recently drawn intense attention as potential photovoltaic materials. However, n = 1 two-dimensional (2D) HOIPs face the challenge of low conductivity between the inorganic layers, leading to unsatisfactory device performance. Interestingly, 2D HOIPs employing pi-conjugated molecules as organic moieties show energy and charge transfers between organic and inorganic layers, indicating potentially efficient carrier transport for photovoltaic applications. Nevertheless, the development of 2D HOIP-based solar cells especially utilizing polycyclic aromatic alkylammonium as cations is in its infancy. Herein, we investigated the electronic structure and band alignment of a series of n = 1 2D Ruddlesden-Popper (RP) phase HOIPs containing different polycyclic aromatic groups and alkyl chains, based on density functional theory calculations. We find that the polycyclic aromatic group plays an important role in controlling the functionality of 2D HOIPs by directly modifying band-edge states, and the band alignment at the organic-inorganic interface can be designed to promote either exciton trapping or dissociation for light-emitting or photovoltaic applications, respectively.

Automated summary

Recent studies have shown that two-dimensional hybrid organic-inorganic perovskites (HOIPs) with pi-conjugated molecules as organic moieties exhibit energy and charge transfers between the organic and inorganic layers, suggesting efficient carrier transport for photovoltaic applications. By utilizing density functional theory calculations, researchers have found that the polycyclic aromatic group in n = 1 2D Ruddlesden-Popper phase HOIPs plays a critical role in controlling the functionality of the materials, and the band alignment at the organic-inorganic interface can be tailored to either promote exciton trapping or dissociation for specific applications.