Fluorescence Quantum Yield of Aromatic Hydrocarbon Crystals

We measured the nuorescence quantum yield ((phi(f)) of several aromatic hydrocarbon crystals: p-terphenyl, trans-stilbene, anthracene, pyrene, and alpha-perylene. The of is reduced by chemical impurities, structural defects, and reabsorption of fluorescence. To minimize the effect of chemical impurities and structural defects, we evaluated the of of highly purified single crystals. We also measured the phi f of powder samples prepared by the mechanical milling of single crystals to assess the effect of reabsorption and structural defects induced by milling. We estimated the lower limit values of the phi(f) to be 0.80 for p-terphenyl, >0.65 for trans-stilbene, >0.64 for anthracene, 0.68 for pyrene, and 0.31 for alpha-perylene.