Surface and Interface Passivation for Perovskite Devices

Perovskite photovoltaics have made remarkable progress in the last decade, with the best lab perovskite cell now achieving over 26% power conversion efficiency. The key to this rapid improvement lies in understanding and controlling the interfaces in perovskite solar cells. In this talk, I will focus on interface engineering in perovskite solar cells (e.g., energy alignment, doping, and carrier dynamics), including the construction of heterostructures of multi-dimensional perovskites. I will discuss surface passivation by synthesizing 2D perovskites atop 3D bulk perovskite. The precise control over the dimensionality of these quantum-confined 2D thin layers enables us to achieve efficient carrier transport across the interface while maintaining desirable trap passivation. I will also discuss field-effect passivation when the perovskite active layer is in contact with a carrier transport layer. Modulating the minority carrier population at the perovskite/C60 interface is critical for reducing interfacial recombination. Lastly, I will explore how we combine chemical and field-effect passivation to achieve optimal passivation. Adjusting interface conditions will be even more important as we move towards multi-junction device architecture in pursuit of higher efficiency.