| Autor: |
Herbert PJ; Department of Chemistry, The Pennsylvania University, University Park, Pennsylvania 16802, United States., Ackerson CJ; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States., Knappenberger KL Jr; Department of Chemistry, The Pennsylvania University, University Park, Pennsylvania 16802, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
The journal of physical chemistry letters [J Phys Chem Lett] 2021 Aug 12; Vol. 12 (31), pp. 7531-7536. Date of Electronic Publication: 2021 Aug 04. |
| DOI: |
10.1021/acs.jpclett.1c02100 |
| Abstrakt: |
Near-infrared photoluminescence of a series of three gold monolayer protected clusters (MPCs) with volumes spanning 50-200 Å 3 was studied by using variable-temperature photoluminescence (VT-PL) spectroscopy. The three MPCs, which included Au 20 (SC 8 H 9 ) 15 -diglyme, Au 25 (SC 8 H 9 ) 18 , and Au 38 (SC 12 H 25 ) 24 , all exhibited temperature-dependent intensities that reflected a few-millielectronvolt energy gap that separated bright emissive and dark nonradiative electronic states. All clusters showed increased PL intensities upon raising the sample temperature from 4.5 K to a cluster-specific value, upon which increased sample temperature resulted in emission quenching. The increased PL in the low-temperature range is attributed to thermally activated carrier transfer from dark to bright states. The quenching at elevated temperatures is attributed to nonradiative vibrational relaxation through Au-Au stretching of the MPCs metal core. Importantly, the results show evidence of a common and size scalable metal-centered intraband PL mechanism that is general for ultrasmall metal nanoclusters, which are expected to show nonscalable optical properties. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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