Synthesis the hybrid materials composing of one-dimensional semiconductor and metal nanostructures for artificial photocatalysis.

Project leader's name
Dr. Hoangg Vu Chung
Research hosting institution
Institute of Materials Sciences
Project duration
2015 - 2017
́Project’s budget
600 million Vietnam Dong
Featured image
Hình ảnh nổi bật
Goal and objectives of the project

General goal and objectives:
Based on the initial results obtaining from the project of the National Key lab, Institute of Materials Science, it is proposed that the general goal of this project is to establish a research direction in PLASMONICS at the Institute of Materials Science, setting a fruitful international collaboration with oversea partners in the field. In the project, we will focus on various plasmonic nanostructures namely nanoparticles, nanorods, network of randomly distributed nanoparticles with resonant wavelengths from visible to near infrared and study on their applications in artificial photocatalysis.

Specific goal:

a) Establish a research direction combining fundamental research in plasmonics and its applications in the artificial photocatalytic activity in the visible frequencies of the semiconductor materials. The central focus are the gold nanoparticles and gold nanorods in contact with one-dimensional TiO2 or ZnO semiconductor materials.
b) Study on the origin of the enhancement of the photocatalytic activity of these materials in the visible frequency. Specifically, the investigation of the photodegradation of methylene blue solution under the visible illumination in the presence of the hybrid materials will be investigated. In addition, the charge-transfer effect between the metal nanostructures and semiconductor nanostructures under the resonant excitation will be studied.
c) Establish an international collaboration with groups of Prof. Tadaaki Nagao (NIMS, Japan), and other potential partners: Prof. Youngpak Lee (Hanyang Univ.) and RMIT (Australia). The collaboration is expected to foster the research output and contribute to the education of young scientist.
d) Participate the international conferences and publish 01 article in ISI standard and another 01 paper.

Main results

Scientific output:
- We have fabricated various plamonic nanoantennas: nanoparticles, nanorods and network of randomly distributed Au nanostructures with the nanogaps in between.
Result: The AuNPs with spherical shape, average diameter of 13 ± 2 nm. The Au nanorods have the controllable aspect ratio, the width is 15 nm, length from 35nm to 90nm, resonant wavelength can be controlled experimentally from 640 nm to 780 nm. The randomly distributed Au network has the controllable gap size and broadband resonance, covering from visible to the near infrared frequencies.
- We synthesized the one-dimensional semiconductor nanostructures made of TiO2 in the FTO/glass substrates.
Results: the TiO2 nanowires were synthesized with average diameter of ~ 10 nm, and length up to several hundred nm. The TiO2 nanowires have the anatase character without the need of further heat treatment.
- We synthezed the one-dimensional ZnO nanorods in the FTO substrate without the need of having the ZnO seed layer. The method is Galvanic based and was throughly investigated which enabled the control in size, shape and length of the ZnO nanorods.
Results: The mechanism for the formation of the ZnO nanorods was investigated systematically, from the very beginning during the formation of the seed particles. Subsequently, the optimal condition for the growth of ZnO nanorods is found. The ZnO nanorods were vertically grown on the FTO with average ~ 100-200 nm, length can be up to 2 μm and more.
- We investigated the artificial photocatalytic activity of the hybrid materials AuNPs@TiO2 and AuNPs/ZnO. We studied the charge transfer process from nano AuNPs to the ZnO (TiO2).
Kết quả: The visible photocatalytic activity of the hybrid materials AuNPs@TiO2 and AuNPs/ZnO were studied. The hybrid materials AuNPs@TiO2 exhibited the rate constant two-fold larger than the other materials. The hybrid materials with the urchin-like ZnO nanostructures displayed the rate constant 30% higher than that of the conventional ZnO nanorods. The mechanism for the charge transfer is studied by the FDTD simulations.
- We studied on the enhancement of the vibration signals of molecules in the strongly coupled plasmonic systems. The system consists of the nano antennas AuNPs in the coupling regime with the infinite Au film seperated by the ZnO film. Thickness of the ZnO film can be controlled experimentally, hence the coupling can also be controlled.
Result: a new vibration mode of ZnO is measured via laser excitation in the Raman measurement. The signal strength is increased if the thickness of ZnO layer increased.
- We established an international collaboration in the field of plasmonics between the scientists at IMS, VAST; Hayang Univ and MANA, NIMS.
Results: we published one article in Scientific Reports (Nature publishing group).
- In application
The results obtained in this project might serve as the major pillar for the next steps of research in plasmonics at IMS and VAST. The next direction can be focused on the energy issues such as plasmonic photovoltaic, further research in artificial photocatalysis and photon conversion.

Some images of the project: 


Novelty and actuality and scientific meaningfulness of the results

The major novelties of this project are:
-We found the high performance of the hybrid materials AuNPs@TiO2 with the photocatalytic activity two-fold higher than that of the other nanostructures. This is due to the ultra-small dimension of the TiO2 nanowires (diameter below 10nm).
-We found a new Raman mode of ZnO material in the strongly coupled plasmonic nanostructures. However, this result need to have further inverstigation
-We found the enhancement of the bio molecule vibration in the terahertz frequencies.

Products of the project

- SCI journals
1) Viet V. Tran, Oanh T. T. Nguyen, Chi H. Le, Tuan A. Phan, Ban V. Hoang, Thang D. Dao, Tadaaki Nagao and Chung V. Hoang, Sub-10nm, high density titania nanoforests - gold nanoparticles compositefor efficient sunlight-driven photocatalysis, Japanese journal of applied physics, 56 095001 (2017).
Doi: 10.7567/JJAP.56.095001
2) Chi H. Le, Oanh T. T. Nguyen, Hieu S. Nguyen, Long D. Pham and Chung V. Hoang
Controllable synthesis and visible-active photocatalytic properties of Au nanoparticles decorated urchin-like ZnO nanostructures, Current Applied Physics, 17 1506-1512 (2017).
Doi: 10.1016/j.cap.2017.08.015
3) Tung S. Bui, Thang D. Dao, Luu H. Dang, Lam D. Vu, Akihiko Ohi, Toshihide Nabatame, YoungPak Lee, Tadaaki Nagao, and Chung V. Hoang, Metamaterial-enhanced vibrational absorption spectroscopy for the detection of protein molecules. Scientific Reports 6 32123 (2016).
Doi: 10.1038/srep32123
- International conference
Dat Q. Tran, Oanh T. T. Nguyen, Chi H. Le, Tuan A. Phan, Long D. Pham and Chung V. Hoang, "Elucidating the growth mechanism of well-aligned ZnO nanorods on conducting substrates without seed layer by galvanic effect". The 7th International Workshop on Advanced materials science and nanotechnology, Ha Long City, Vietnam, 2-6 November, 2014
Dat Q. TRAN, Cat V.Vu, Chi H. LE, Long D. PHAM and Chung V. HOANG, "Radiation Damping Assisted Raman Scattering Enhancement of Plasmonic Nanoparticles in Semiconductor Nanostructures " The 5th International Workshop on Nanotechnology and Application - IWNA 2015, 11 -14 November 2015 - Vung Tau, Vietnam
Quynh N. Nguyen, Cat V. Vu, Dat Q. Tran, Oanh T. T. Nguyen, Long D. Pham, Thang D. Dao, Tadaaki Nagao and Chung V. Hoang, "Electromagnetic coupling of Au nanoparticles and conducting substrates for plasmonic solar cell applications." The 7th International Workshop on Advanced materials science and nanotechnology, Ha Long City, Vietnam, 2-6 November, 2014
Viet V. Tran, Chi H. Le, Long D. Pham, Oanh T. Nguyen, Thang D. Dao, Tadaaki Nagao, Tuan A. Phan, and Chung V. Hoang, " Hybrid materials: free-standing TiO2 nanowires - Au nanoparticles for artificial photo catalysis application." The 7th International Workshop on Advanced materials science and nanotechnology, Ha Long City, Vietnam, 2-6 November, 2014
-Technological products:
1. Procedure for the synthesis of plasmonic nanostructures: nanoparticles, nanorods and network of randomly distributed nanoparticles
2. Procedure for the synthesis via hydothermal route of the one-dimensional TiO2 nanowires on FTO/glass substrates.
3. Procedure for the synthesis of the ZnO nanorods grown vertically on the FTO substrate via Galvanic effect.
4. 20 devices (10 for each) of AuNPs@TiO2 and AuNPs@ZnO, dimension 2cm  2cm.
-Educational result:



We hope to continue this direction of research in order to promote a strong research team and promissing research direction.

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