Highly luminescent semiconductor nanoparticles immobilized in a polymer matrix using environmentally benign supercritical CO2
Semiconductor nanocrystals known as quantum dots (QDs) are increasingly being used as photoluminescent materials in bio-imaging, photonics, and optoelectronic applications.
However, these QDs must have stable photoluminescence properties to be used in these applications. Photoluminescence stability of QDs is achieved by chemically modifying the surface of the QDs.
However, chemical modification of the surface typically requires large amounts of organic solvents that are harmful to the environment. To solve this problem, many researchers have attempted to synthesize polymer-nanoparticle composites by using supercritical fluid (SCF)-based technology.
Supercritical CO2 has emerged as the most extensively studied SCF medium, because it is readily available, inexpensive, nonflammable, and environmentally benign.
Toyohashi Tech researchers in cooperation with researchers at the National Institute of Technology, Kurume College have investigated the formation of nanostructured material using supercritical CO2.
They have demonstrated the formation of composite nanoparticles of luminescent ZnO QDs and polymer by dispersion polymerization in supercritical CO2. As a result of the supercritical-CO2-assisted surface modification of QDs, the QDs were well dispersed in the polymer matrix and showed high luminescence.
"Unfortunately, the photoluminescence properties of pristine luminescent QDs were quenched in supercritical CO2. The surface structure of the QDs was destroyed by supercritical CO2.", explains associate professor Kiyoshi Matsuyama at the National Institute of Technology, Kurume College, "We found that the quenching of ZnO QDs could be prevented by coating with silica to obtain PMMA-ZnO composite QDs with high luminescence using a supercritical-CO2-assisted surface modification with polymer."
Our research shows that the supercritical-fluid-assisted process provides an environmentally benign route for producing stabilized luminescent materials.
Kiyoshi Matsuyama, Yu-ki Maeda, Takaaki Matsuda, Tetsuya Okuyama, Hiroyuki Muto (2015)
Formation of poly(methyl methacrylate)-ZnO nanoparticle quantum dot composites by dispersion polymerization in supercritical CO2, The Journal of Supercritical Fluids, 103, 83-89.
This article was identified as the "Editor-in-Chief's Featured Article." http://www.
Related studies are featured in the September 2015 issue of TUT Research:
Michiteru Kitazaki | EurekAlert!
Custom sequences for polymers using visible light
22.03.2018 | Tokyo Metropolitan University
The search for dark matter widens
21.03.2018 | American Institute of Physics
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences