To understand the influence of a small ΔELUMO on LPL, we compared the TL and relative temperature- PPT become stronger over 150 K, indicating more efficient trap filling at higher temperatures . Because such thermally activated trap filling is not observed in 2,8-PPT alone but is more pronounced in the DAAPC/2,8-PPT, more deep traps were filled in the small ΔELUMO system at room temperature, resulting in stronger LPL.