Energy transfer studies between mixed Au-Pd cyanide nanosystems and Tb+3 doped in different alkali halides

Abstract

Heterometallic d10-d8 nano systems of dicyanoaurate(I) and tetracyanopalladate(II) with Tb+3 doped in different alkali halide hosts (NaCl, NaBr, and KBr) have been studied. This is the first time three such ions have been synthesized and studied in alkali halide hosts. Raman measurements were performed to elucidate the nature of the nanocluster structures. Vibrational measurements reveal that Tb+3 substitution of the alkali halide does not occur without regard to the dispersion and configuration of Au(CN)2−/Pd(CN)4−2 codopants. Low temperature luminescence measurements show broad emission bands associated with a combination of Au(CN)2− and Pd(CN)4−2 MLCT. Terbium f-f emission bands are observed with intensities on the order of KBr > NaBr > NaCl, counter to the higher concentration of Tb+3 in NaCl. Our results indicate that f-f emissions arise from resonance energy transfer from a mixed Au/Pd nanocluster, which preferentially form in larger alkali halide hosts. We support our findings using DFT calculations.