Photoluminescence of 8-hydroxyquinoline aluminum in porous silicon

Two methods were used to assemble organic molecule 8-hydroxyquinoline aluminum (Alq3) into the pores of porous silicon (PS) which was prepared by anodization. At first, Alq3 was impregnated into the pores by physical adsorption when a fresh PS sample was immerged into chloroform solution of Alq3. In the second, PS was immersed into aqueous solution of Al2(SO4)3, Alq3 was obtained in the pores by chemical reaction when methanol solution of 8-hydroxyquinoline was slowly injected. The photoluminescent (PL) spectra showed blue shift and narrower bandwidth relative to the PL of Alq3 film on silicon wafer. PL intensity of the reaction sample was much higher than that of the impregnation sample. These results indicated that PL spectrum of Alq3 was confined in the pores and the first way was more effective than the second one.