Figure 4

Schematic illustration of the polychromatic spectroscopy system. The UPE spectra of the samples were measured using a polychromatic spectrum analysis system, which consists of a transmission-type diffraction grating, condenser lens, collimator lens, input slit, and cooled CCD camera. The samples were irradiated with UVA outside of the dark chamber and were then immediately placed under a 1 mm wide and 20 mm high optical input slit in the dark chamber of the spectroscopic system.