Uda Kyota, Tsuda Yuki, Okada Shuji, Yamakado Ryohei, Sun Lina, Suzuri Yoshiyuki, White Matthew Schuette, Furis Madalina, Stadler Philipp, Dimitriev Oleg, Yoshida Tsukasa
Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
Department of Physics, University of Vermont, Burlington, Vermont 05405, United States.
ACS Omega. 2019 Feb 22;4(2):4056-4062. doi: 10.1021/acsomega.8b03632. eCollection 2019 Feb 28.
Hybrid thin films of crystalline CuSCN and 4-(,-dimethylamino)-4'-('-methyl)stilbazolium (DAS) in three distinctively different nanostructures were obtained by electrochemical self-assembly from a single pot containing all the chemical ingredients. Their optical properties for UV-vis-NIR absorption, photoluminescence (PL), and PL excitation spectra were examined between 77 and 298 K, in comparison with solution and solid powder of DAS tosylate (DAST). Unlike all other dyes we tested before, PL of DAS was not quenched but rather enhanced when hybridized with CuSCN. DAST exhibited a strong exciton-phonon coupling to weaken, broaden, and red shift PL at room temperature, so that it inversely is strongly enhanced, sharpened, and blue-shifted at 77 K. The PL of the same dye in the hybrid thin film, however, shows a slight red shift and only a moderate enhancement at reduced temperatures due to strong exciton stabilization in dielectric environment of CuSCN and concerted PL by energy transfer from CuSCN to DAS luminophore, making it a unique nearly temperature-independent luminescent material.
