Photoluminescence from metal clusters formed in the pores of zeolite by pulsed laser ablation in a liquid phase

Laser ablation (LA) in a liquid was used for loading clusters on various supporting materials. An advantage of LA in a liquid is that the cluster generation conditions are almost independent of the material. Gold, silver, and copper clusters were implanted in the pores of zeolite particles using a laser ablation of an Au, Ag, or a Cu plate in water dispersed with zeolite ZSM-5 particles. We found the evidence for Au and Ag clusters trapped in the pores of the zeolite through LA in water that the samples fluoresced between 400 and 500 nm under 350 nm excitation after calcination at 300 ℃. However, the sample with Cu did not exhibit PL because the Cu particles produced by LA in water were oxidized. The Au and Ag clusters were estimated to be composed of ~6 atoms based on the relationship between the HOMO–LUMO energy gap and the cluster size predicted using the jellium model.