To enhance the LPL of DAAPC/2,8-PPT, we incorporated two more compounds, m-BTB and PPTDO, as extrinsic electron traps (Fig. ). Their LUMO levels are 0.54 and 0.79 eV deeper than that of 2,8-PPT, respectively. Given that optical gaps of these traps significantly exceed the CT gap of DAAPC/2,8-PPT, the PL and LPL spectra of the final doped systems remain largely consistent with those of DAAPC/2,8-PPT, and the minor variations can be attributed to respective radical ion absorption (Extended Data Fig. ). Currently, LPL lacks intrinsic evaluation parameters, and its brightness and duration depend on the excitation conditions and samples, resulting in a lack of comparability across publications 3 -5, 10 -15, 22, 44 -46 . Therefore, as a practical benchmark, we used the ISO standard conditions for safety signs of LPL materials (ISO 17398). Although our sample is only 0.5 mm thick, m-BTB/DAAPC/2,8-PPT achieved Class A under ISO 17398, which is the entrylevel for safety sign application, making it arguably the brightest OLPL material to date (see Supplementary Information 4.14). However, the LPL of PPTDO/DAAPC/2,8-PPT was weaker than that of DAAPC/2,8-PPT on short time scales, likely because of the absorption peak of the PPTDO radical anions in the 400-700 nm range (Extended Data Fig. ). Because the luminance used in ISO 17398 is based on photopic vision, the scotopic luminance of these two materials should be stronger.