To ascertain the 1 LED to CT upconversion in the small ΔELE-CT systems, we performed wavelengthresolved TL measurements (Figs. 4a-f, Extended Data Fig. ). TL and LPL are intrinsically linked, reflecting the charge recombination luminescence induced by the thermally stimulated de-trapping of carriers and do not include the initial singlet and triplet excitons generated directly by photoexcitation . In the 1 LED emission dominant system, DAAPC/DPEPO, and the 1 CT emission dominant systems of DAAPC/3,7-PPT and DDATA/2,8-PPT, the spectral onset remained consistent from low to high temperatures. However, the