In situ generation of fluorescent silver nanoclusters in layer-by-layer assembled films
作者：Wenjing Zhang; Jia Song; Wang Liao; Ying Guan; Yongjun Zhang; X. X. Zhu
關(guān)鍵字：Ag nanoparticle; fluorescent; layer-by-layer
論文來源：期刊
具體來源：Journal of Materials Chemistry C
發(fā)表時間：2013年
Fluorescent Ag nanoclusters have been easily generated in layer-by-layer (LBL) fi lms of poly(vinyl
pyrrolidone) (PVPON) and poly(acrylic acid) (PAA) by photo-reduction of Ag + ions, which were
previously loaded via an ion exchange mechanism. Under UV irradiation, Ag + ions were reduced to Ag
atoms by the photo-generated radicals and then aggregate to form fl uorescent nanoclusters. The Ag +
concentration plays a key role in the determination of the growth rate of Ag particles. Careful tuning of
the Ag loading in the fi lm prevented the growth of the fl uorescent nanoclusters into larger non-
fl uorescent nanoparticles. Fluorescent Ag nanoclusters can be generated in both wet and dry fi lms.
However, the fl uorescence intensity achieved in dry fi lms is lower than that in wet fi lms because the
tight con fi nement of the polymer network retards the di ff usion and aggregation of the photo-
generated Ag atoms. Interestingly the fl uorescence intensity can be enhanced signi fi cantly by a post-
treatment in water, as it allows the Ag atoms to di ff use and aggregate to form more fl uorescent
nanoclusters. This work shows that the PVPON/PAA LBL fi lms can serve as nanoreactors that allow the
in situ generation of fl uorescent Ag nanoclusters, yielding fl uorescent Ag nanoclusters in a technically
important form, in addition to providing a simple way to control the growth of the nanoparticles.