Direct operando observation and control of charge states in organic light-emitting diodes with a thermally activated delayed ｧuorescence material Shintaro Yumoto University of Tsukuba Junya Katsumata University of Tsukuba Fumiya Osawa University of Tsukuba Yoshimasa Wada Kyoto University Katsuaki Suzuki Kyoto University Hironori Kaji Kyoto University https://orcid.org/0000-0002-5111-3852 Kazuhiro Marumoto (  marumoto@ims.tsukuba.ac.jp ) University of Tsukuba https://orcid.org/0000-0001-9792-0775 Article Keywords: Posted Date: February 28th, 2023 DOI: https://doi.org/10.21203/rs.3.rs-2581139/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Additional Declarations: There is NO Competing Interest.