The separated contributions of H, Br, Cs, and Pb radical species resulted from the fitting of the measured EPR spectra after 24 min of illumination for both CsPbBr3 and Cs4PbBr6 NCs in Sol. 1 and 2 are presented in Figure . As the illumination time increases, the signal weakens, which indicates that the radicals produced due to the decomposition of HPs diminish. We find that after 24 min, both CsPbBr3 and Cs4PbBr6 NCs are decomposed to a high degree, as indicated by the shape and the intensity of the EPR spectra.