Trap states, electric fields, and phase segregation in mixed-halide perovskite photovoltaic devices
| Autor: | Jay B. Patel, Alexander J. Knight, Laura M. Herz, Michael B. Johnston, Henry J. Snaith |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Photoluminescence
Materials science Renewable Energy Sustainability and the Environment Band gap Halide 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Crystal Chemical physics Electric field General Materials Science Grain boundary Quantum efficiency 0210 nano-technology Perovskite (structure) |
| Popis: | Mixed-halide perovskites are essential for use in all-perovskite or perovskite–silicon tandem solar cells due to their tunable bandgap. However, trap states and halide segregation currently present the two main challenges for efficient mixed-halide perovskite technologies. Here photoluminescence techniques are used to study trap states and halide segregation in full mixed-halide perovskite photovoltaic devices. This work identifies three distinct defect species in the perovskite material: a charged, mobile defect that traps charge-carriers in the perovskite, a charge-neutral defect that induces halide segregation, and a charged, mobile defect that screens the perovskite from external electric fields. These three defects are proposed to be MA+ interstitials, crystal distortions, and halide vacancies and/or interstitials, respectively. Finally, external quantum efficiency measurements show that photoexcited charge-carriers can be extracted from the iodide-rich low-bandgap regions of the phase-segregated perovskite formed under illumination, suggesting the existence of charge-carrier percolation pathways through grain boundaries where phase-segregation may occur. |
| Databáze: | OpenAIRE |
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