Device Architecture for Perovskite Photovoltaics

Over the past decade, perovskite photovoltaics facilitated by solution-processed metal halide perovskites have garnered significant attention in both academic and industrial sectors. Studies demonstrated that device architecture plays a crucial role in the device-performance of perovskite photovoltaics. In this review, we summarize the evolution of device architectures of perovskite photovoltaics, mesoporous scaffold, planar heterojunction, and bulk heterojunction, centered on "core challenges driving structural evolution" as the main theme and driving momentum to develop an analytical framework that ties device architectures to charge transport, defects, and ion migration management. We outline these three device architectures using a template of "advantages - limitations - improvement paths" anchored in the three key dimensions: efficiency, stability, and scalability. We explicitly analyze both mesoporous scaffold and planar heterojunction device structures, particularly correlating device architecture with the core challenges for boosting and manufacturing perovskite photovoltaics. We describe the motivation for developing a bulk heterojunction. Afterward, we summarize the advantages of bulk heterojunction device structures through a controllable interpenetrating network with nanoscale phase separation, which enables local band microalignment, minority-carrier highways, Fermi-level repositioning, charge transport balancing, ion-migration restriction, and bulk/grain boundary defect passivation. Lastly, we envision future research focusing on the bulk heterojunction and providing a roadmap to guide scale-up and accelerate the commercialization of perovskite photovoltaics.