Contact

  • Academic
    fnitta@stanford.edu
    University - Student Department: Chemistry Position: Undergraduate
    University - Student Department: Electrical Engineering Position: Undergraduate
    University - Student Department: Computer Science Position: Undergraduate
    University - Student Department: Materials Science and Engineering Position: Graduate

Additional Info

  • Mail Code: 9505

All Publications

  • High-specific-power flexible transition metal dichalcogenide solar cells. Nature communications Nassiri Nazif, K., Daus, A., Hong, J., Lee, N., Vaziri, S., Kumar, A., Nitta, F., Chen, M. E., Kananian, S., Islam, R., Kim, K., Park, J., Poon, A. S., Brongersma, M. L., Pop, E., Saraswat, K. C. 2021; 12 (1): 7034

    Abstract

    Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coefficients, desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact-TMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addition, fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightweight flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4Wg-1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46Wg-1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics.

    View details for DOI 10.1038/s41467-021-27195-7

    View details for PubMedID 34887383