TOSPEL Transient operando spectroscopy of perovskite nanocrystal LEDs

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Meeting the substantially growing demand for lighting with limited environmental impact relies on technological developments delivering an energy-efficient lighting system. Metal-halide perovskites have emerged as a new class of semiconductors that creates opportunities to revolutionize the way we convert electrical energy into light. Perovskite nanocrystal light-emitting diodes (LEDs) have enormous potential to be the next generation of LEDs due to their low fabrication cost, high efficiency, bandgap tunability, and high color purity. Despite the advantages of perovskite nanocrystal LEDs, the inevitable nanocrystal size distribution, shape difference, and surface states lead to the co-existence of multiple dynamic processes that influence the optoelectronic properties and the operational stability of the LEDs. This project is titled "Transient operando spectroscopy of perovskite nanocrystal LEDs" (TospeL). Novel ultrafast absorption and emission spectroscopic techniques combining periodic electrical excitations and femtosecond optical pulses will be designed and applied to perovskite nanocrystal LEDs. The applicant will join the Bawendi Group at MIT (outgoing phase) to synthesize perovskite nanocrystals and fabricate nanocrystal LEDs with desirable optical properties, which will be used for ultrafast dynamics studies using newly designed transient operando emission techniques in the Bawendi Group. For the return phase, the applicant will join the Stranks Group at University of Cambridge to design and implement transient absorption spectroscopy to investigate the interactions between excitons, carriers, traps, and spin as well as the recombination mechanisms in working LEDs. These results will give a new comprehensive understanding of LEDs photophysics and provide guidance for their further development.