Perovskite Solar Cell Architecture without Charge Transport Materials

State-of-the-art perovskite solar cells (PSCs) employ a multilayer device structure, incorporating a combination of charge transport layers and interfacial modifications to achieve efficient charge extraction. However, simplifying the device structure is highly desirable for cost-effective mass production. One promising approach is to integrate multiple functionalities into one single molecule, which effectively replicates the functions that a multilayer structure provides. To explore this concept, we propose a device architecture where a combination of p-type and n-type self-assembled monolayers are employed to construct the hole-extraction and electron-extraction interfaces in a PSC without charge transport layers or additional modifications. The resulting device successfully establishes charge selectivity, achieving a substantial photovoltaic output and promising stability not far from those of state-of-the-art PSCs. Our findings suggest that replacing the complex multi-layered junction interfaces with functional monolayer interfaces is a promising approach to make efficient solar cells with a minimum demand of materials and a simple fabrication process. The proposed device architecture could be extended to other types of thin-film electronic devices and opens up a new pathway to achieve high efficiency by designing the interfaces at the molecular level.