Fig. 2. (A) The normalized steady-state PL spectra of CS-2COOCH₃ in different states—crystal, ground state and doped in poly(methyl methacrylate) (PMMA) film in air. (B) The fluorescence decay curves of CS-2COOCH₃ crystal at 405 and 505 nm in air. (C) The RTP spectra, acquired after 10 ms delay, of CS-2COOCH₃ in different states—crystal, ground state and doped in PMMA film under air atmosphere. (D) The RTP decay curves of CS-2COOCH₃ crystal at 430, 460 and 490 nm. Insets: photos of CS-2COOCH₃ crystal before and after turning off 365 nm UV radiation in air.