Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV16)
Publication date: 28th March 2016
Recently developed organic-inorganic hybrid perovskite solar cells combine low-cost fabrication and high power conversion efficiency. Advances in perovskite film optimization have led to an outstanding power conversion efficiency of more than 20 % within only five years of development. Looking forward, shifting the focus towards new device architectures and interface engineering holds the great potential to induce the next leap in device performance. Here, we report the first demonstration of a perovskite/perovskite heterojunction solar cell. We developed a facile solution-based cation infiltration process to deposit layered quantum well-like (QW) perovskite structures onto methylammonium lead iodide (MAPI) films. Grazing-incidence wide angle X-ray scattering experiments were performed to gain insights into the crystallite orientation and the formation process of the perovskite bilayer. Our results show that the self-assembly of the QW perovskite layer on top of an intact MAPI layer is accompanied by a reorganization of the perovskite interface. This leads to an enhancement of the open-circuit voltage and power conversion efficiency, as well as improved moisture stability in the resulting photovoltaic devices. Our work opens new doors to all-perovskite heterojunction architectures for highly efficient perovskite solar cells.