Dr Tsoi is leading a research group on next generation photovoltaic (PV) cells particular on organic PV cells and perovskite PV cells, including developed several new/advanced Raman system-based techniques, and facilities for PV for indoor, aerospace and power implants applications. His current research includes developing new/advanced Raman-based techniques, understand and improve stability of organic and perovskite PV cells, optimize performance of organic and perovskite PV cells for emerging applications (for indoor, power generation window, aerospace, and power implants applications). Dr Tsoi has particularly expertise in new/advanced characterization techniques to understand structure-property-performance relationship of printable PV cells, particularly world-leading in Raman spectroscopy for organic and perovskite PV cells. Due to his development of novel Raman system-based multi-mapping techniques, Dr Tsoi was awarded the "2021 Winner of the Medal for Innovation in Applied Microscopy for Engineering and Physical Sciences (Royal Microscopy Society)". He is also one of the world leaders in indoor PV, PV for aerospace applications and PV for powering biomedical implants (achieved highest efficiency and have several pioneering findings). Dr Tsoi had published 95 papers including in Science, Nature communications, Energy and Environmental Science, Advanced Materials, Advanced Energy Materials, Journal of the American Chemical Society, and a book chapter. He also involved in 79 oral presentations in international/national conferences including 37 invited talks.