Abstract
Solution-processable perovskite nanocrystals (NCs) are gaining increasing interest in the field of photovoltaics because of their enhanced stability compared to their thin-film counterparts. However, the charge transfer dynamics in perovskite NC based light-harvesting systems are not well understood. By applying femtosecond differential transmission (DT) spectroscopy the photoinduced charge transfer from inorganic perovskite CsPbBr3 NCs to the fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) is investigated for two fundamentally different architectures, namely layer-by-layer heterostructures and blend structures. By varying the thickness of the NC layer on top of the PCBM in the layer-by-layer heterostructure, an exciton diffusion length of 290 +/- 28 nm for CsPbBr3 NC is extracted. The diffusion process is followed by an ultrafast exciton dissociation (within 200 fs) at the CsPbBr3 NC/PCBM interface. In blend structures an overall faster charge transfer process is observed. Furthermore, photoconductivity measurements on a blend structure-based photodetector reveal an effective charge extraction from the active layer resulting in a high photosensitivity. DT measurements on this blend structure including adjacent electron- or hole-transport layers give insight into the extraction process and suggest a certain degree of phase segregation, which assists the charge collection.
| Item Type: | Journal article |
|---|---|
| Faculties: | Physics |
| Research Centers: | Center for NanoScience (CENS) |
| Subjects: | 500 Science > 500 Science 500 Science > 530 Physics |
| ISSN: | 2195-1071 |
| Language: | English |
| Item ID: | 84183 |
| Date Deposited: | 15. Dec 2021 15:10 |
| Last Modified: | 15. Dec 2021 15:10 |
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