Figure 5.

(a) Optical absorption (solid line) of the 4:1 DMSO powder sample obtained by converting reflectance (R) to absorption using the Kubelka-Munk equation,⁶ F(R)=(1-R)²/2R, and PL emission (dotted line) at the excitation wavelength of 405 nm. (b) Confocal PL microscopy image recorded with 488 nm excitation; the PL spectrum from an area highlighted by the white square is shown in Figure S7