A few days ago, the research group of Changchun Institute of Light Machinery, Chinese Academy of Sciences Qu Songnan’s group broke through the problem of low luminous efficiency of carbon nanodots in the near-infrared region, and for the first time developed carbon nanodots with high-efficiency near-infrared absorption/emission characteristics, and realized carbon nanodots based on carbon nanodots. In vivo near-infrared fluorescence imaging.
In recent years, Qu Songnan led the research group to frequently publish articles in high-impact journals. Qu Songnan who joined the work in 2009 has independently brought the research team after several years of work, and has therefore been promoted to a research fellow.
Focus on carbon nano dots
Qu Songnan pointed out that luminescent carbon nanodots are emerging nano luminescent materials, with small size (less than 20 nm), non-toxic, good luminescent properties, good biocompatibility, good light stability, wide raw materials, and easy modification , aroused widespread concern at home and abroad.
Earlier, research on luminescent inorganic semiconductor nanoparticles was very active. However, inorganic semiconductor nanoparticles generally contain heavy metal cores (lead, cadmium), which are toxic and harmful to the environment. Therefore, scientists began to prepare new non-toxic compounds. Glowing nanoparticles.
In 2006, scientists at Clemson University in the United States produced a type of carbon nanoparticle that emits bright light in the presence of light. Scientists also discovered that luminescent carbon nanoparticles have unique advantages, such as chemical stability. No light flicker, light drift, non-toxic, cheaper cost and excellent biocompatibility.
In 2012, the team of Qu Songnan, then an associate researcher at Changchun Optics and Machinery Research Institute, found that using carbon nanoparticles to excite wavelength-dependent properties combined with organic dyes can create information-encrypted graphics on biological products. This can be applied to Information storage and information encryption.
'These unique properties make it possible for carbon nanodots to enter our real life.' Qu Songnan told reporters, and then their team developed a new type of fluorescent ink. 'This ink can be applied to biological imaging, biological product identification , Information storage, information encryption, security, lighting display, sensing, photovoltaic devices and other fields.
Break through the technical bottleneck
It is reported that the research of luminescence mechanism and spectrum control of carbon nanoparticles is a research difficulty in this field. Before 2013, it was internationally believed that the emission of carbon nanoparticles in the green wavelength band originated from the surface defects of carbon nanoparticles, and this luminescence source was Think it is difficult to achieve laser.
To this end, Qu Songnan’s team managed the regulation of blue and green light emitted by carbon nanoparticles through the regulation of nitrogen in carbon nanoparticles, and observed the phenomenon of amplified spontaneous emission of carbon nanoparticles in the green light band, and realized for the first time. Carbon nanoparticles pump light in the green wavelength band.
Qu Songnan recalled: 'In those years, we proved through comparison experiments that the light stability of carbon nano-particles is better than that of traditional organic laser dyes, indicating that carbon nanoparticles can be used as a new type of low-cost, green, and light-stable new type. Laser material is expected to change the future lighting world.
Subsequently, Qu Songnan and his research team proposed the concept of 'super carbon nano dots' for the first time in the world, and developed a water triggered 'nanometer fluorescent bomb' based on 'ultra carbon nano dots', making carbon nano dot material a kind of New smart light emitting materials.
The existing absorption and emission bands of carbon nanodots are mainly located in the ultraviolet-visible region, and can not achieve efficient absorption in the near infrared region and high fluorescence quantum efficiency near-infrared luminescence, which severely limits the carbon nanodots in biofluorescence imaging especially In vivo near-infrared fluorescence imaging applications.
In recent years, in order to solve the problem of high-efficiency near-infrared luminescence, Qu Songnan’s research group has performed the electron-withdrawing group modification on the surface of red-light carbon nano-dots and the disordered regulation of the ordered structure of the carbon-based inner-core layer in the near-infrared. The band generates a new light-emitting bandgap, and carbon nanorods with efficient near-infrared emission under near-infrared excitation are obtained. The fluorescence quantum efficiency reaches 10%, which is the highest in the world.
High-level articles
It is not difficult to find that Qu Songnan’s task force has carried out a lot of research in the regulation and application of luminous carbon nano-bands. Qu Songnan has published 29 SCI papers as the first author or correspondent author, among which the SCI influence factor is more than 10 6 papers, the first author's single paper SCI he cited up to 390 times, cumulative SCI cited 1630 times. Among them, Qu Songnan published two articles selected by the ESI (basic scientific indicator database) hot and highly cited papers, enter the most One thousandth of excellent papers.
Talking about how to publish high-level papers, Qu Songnan said humbly that there are not many skills in this area. First of all, the research direction must be valuable and has application prospects. Second, the research content must be the core problem in the field and the current The main challenge. 'These two points are met, the quality of published articles is naturally not bad.'
At present, Qu Songnan's scientific research plan is to enable carbon nano-dots to achieve clinical application in the field of cancer diagnosis and treatment within 10 years.
He said: 'Compared to existing nano-luminescent materials, luminescent carbon nano-dots are particularly suitable for the development of fluorescent imaging and cancer diagnosis and treatment drugs for living organisms. In addition, the lifetime of carbon nano-spots is only a few nanoseconds, much lower than existing Commercial phosphor has important application potential in the field of high bandwidth visible light lighting communication.
As a young scientific researcher, Qu Songnan suggested that young people engage in scientific research to first look at scientific research conditions and development potentials. 'The state’s orientation to scientific researchers and the various mechanistic measures are getting better and better. As long as young people are willing to work hard, they will be right. It is supported. 'He also hopes that the country will have more inclinations toward the Northeast in terms of its talent policy, and will give more policy support to young researchers in the transformation of achievements.