Cho, Youngho Lim, Soo Yeong Lee, Song Yeul Kim, Jae Hun Park, Yong Il Park, Chan Ryang Kim, Hyung Min 2024-01-19T18:31:08Z 2024-01-19T18:31:08Z 2022-01-25 2020-01 1932-7447 https://pubs.kist.re.kr/handle/201004/119117 Lanthanide phosphors have attracted great interest because of their highly efficient photonic upconversion processes. The upconversion spectra and time-resolved relaxation are influenced not only by the chemical composition of phosphors but also by the excitation characteristics of incident radiation. Despite numerous reports that upconversion spectra strongly depend on the experimental conditions, little research has been reported on the relationship between the temporal profile of excitation and the resulting luminescence spectra. In this study, we introduced time- and frequency-domain pulsed modulation spectroscopy to investigate statistical energy accumulation and relaxation in a NalT(4):Yb3+,Er3+ upconversion process. The modulation of a laser pulse width and interval showed that complete depopulation of hot phosphors required more than 5 ms. Furthermore, we demonstrated that the intermediate state (I-4(13/2)) is populated in hot phosphors and affects upconversion luminescence. English American Chemical Society Statistical Time-Resolved Spectroscopic Study on Upconversion Luminescence Article 10.1021/acs.jpcc.9b09855 1 The Journal of Physical Chemistry C, v.124, no.4, pp.2680 - 2688 The Journal of Physical Chemistry C 124 4 2680 2688 N scie scopus 000510529400046 2-s2.0-85079295010 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article UPCONVERTING NANOPARTICLES INFRARED LIGHT EMISSION RED NANOCRYSTALS MECHANISMS LIFETIME