1) The document discusses investigating perylene as a secondary wavelength shifter for the SNO+ liquid scintillator experiment. 2) It describes experiments measuring the optical absorption and emission spectra of perylene samples mixed in solvents at various concentrations and excitation wavelengths. 3) The results show that perylene's emission spectrum shape remains constant with different excitation wavelengths but intensity varies, and that concentration affects both intensity and spectrum shape due to self-absorption and non-uniform absorption.