The strategy of the upconversion from CT to LE using a small ΔELUMO, meaning a small ΔELE-CT system, enabled a blue-to-cyan LPL matching the mesopic and scotopic vision. Steady-state, transient, and TL spectroscopy measurements were utilized for multiple donor-acceptor combinations with different energy levels to elucidate the complex emission mechanism including fluorescence, TADF, phosphorescence, and LPL. Wavelength-resolved TL measurements provide direct experimental evidence for the upconversion from Blue and red dashed lines emphasize the two emission peaks at the same wavelength position. All spectra transformed from original spectra through Jacobian conversion . g,h, Emission decay profile of DAAPCdoped materials from 100 ps to 10 ms (g) and from 1 ms to 10 4 s (h). Relative time-resolved spectra: see Extended Data Fig. . Spectra and decay profiles of 0.