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Charge-Transfer Process in Surface-Enhanced Raman Scattering Based on Energy Level Locations of Rare-Earth $Nd^{3+}$-Doped $TiO_{2}$ Nanoparticles
| Content Provider | MDPI |
|---|---|
| Author | Zhao, Zihao Zhao, Xiang Zhang, Mu Sun, Xudong |
| Copyright Year | 2021 |
| Description | Surface-enhanced Raman scattering (SERS) for semiconductor nanomaterial systems is limited due to weak Raman signal intensity and unclear charge-transfer (CT) processes for chemical enhancement. Here, rare-earth element neodymium-doped titanium dioxide $(Nd-TiO_{2}$) nanoparticles (NPs) were synthesized by the sol–gel method. The characterizations show that the doping of Nd ions causes $TiO_{2}$ NPs to show an increase in the concentration of defects and change in the energy level structure. The CT process between $Nd-TiO_{2}$ NPs substrate and probe molecule 4-Mercaptopyridine (4-Mpy) was innovatively analyzed using the relative energy level location relationship of the Dorenbos model. The SERS signal intensity exhibits an exponential enhancement with increasing Nd doping concentration and reaches its optimum at 2%, which is attributed to two factors: (1) The increase in the defect concentration is beneficial to the CT process between the $TiO_{2}$ and the probe molecule; (2) the introduction of 4f electron orbital energy levels of rare-earth ions created unique CT process between $Nd^{3+}$ and 4-Mpy. Moreover, the $Nd-TiO_{2}$ NPs substrate shows excellent SERS performance in Raman signal reproducibility (RSD = 5.31%), the limit of detection (LOD = $10^{−6}$ M), and enhancement factor (EF = 3.79 × $10^{4}$). Our work not only improves the SERS performance of semiconductor substrates but also provides a novel approach to the development of selective detection of probe molecules. |
| Starting Page | 2063 |
| e-ISSN | 20794991 |
| DOI | 10.3390/nano11082063 |
| Journal | Nanomaterials |
| Issue Number | 8 |
| Volume Number | 11 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-08-14 |
| Access Restriction | Open |
| Subject Keyword | Nanomaterials Spectroscopy Surface-enhanced Raman Scattering Charge-transfer Nd-tio2 4-mpy Energy Level Location |
| Content Type | Text |
| Resource Type | Article |
