Perovskite Heterojunction Quantum Dot Films with Charge-Separating Interface
June 28, 2019
Metal halide perovskite semiconductors, with chemical composition ABX3, possess outstanding characteristics for optoelectronic applications, including but not limited to photovoltaics.
Semiconductor heterojunctions enable technologies such as specific transistor operations, quantum wells, lasers, and solar cells. Generally, the manufacture of heterojunctions requires precisely controlled deposition. Here, multiple perovskite compositions can be applied successively to explore their synergistic properties and lead to new concepts and devices.
Significance and Impact
Because colloidal perovskite quantum dots are not technically dissolved in solvent but rather suspended by ligands, we deposit perovskite quantum dots in a layer-by-layer fashion. We explore films with a charge-separating interface between layers of CsPbI3 and CsxFA1-xPbI3 where the position of the interface can be controlled as well as the band offsets by tuning the Cs:FA ratio in one of the layers.
- Energy levels of CsxFA1-xPbI3 with systematically controlled x value were probed.
- Heterojunctions were fabricated with tunable driving force and layer thicknesses and probed using transient absorption spectroscopy