Academics

your location: 首页  Academics
Research by ZENG's Team Reported by two top Magazines

Recently, research about the application of luminescent carbon dots (L-CDs) and white LED by NUST Research Institute of Nano Optical and Electronic Material has been progressed with a series of results, which were published on Scientific Reports with Nature Publishing Group (impact factor 5.1) and Angewandte Chemie International Edition with German Wiley Publishing House. First-year postgraduate LI Xiaoming is the first author of both the two articles, and professor ZENG Haibo is the independent corresponding author.

 

Luminescent carbon dots (L-CDs) with high quantum yield value (44.7%) and controllable emission wavelengths were prepared via a facile hydrothermal method. Importantly, the surface states of the materials could be engineered so that their photoluminescence was either excitation-dependent or distinctly independent. This was achieved by changing the density of amino-groups on the L-CD surface. The above materials were successfully used to prepare multicolor L-CDs/polymer composites, which exhibited blue, green, and even white luminescence. In addition, the excellent excitation-independent luminescence of L-CDs prepared at low temperature was tested for detecting various metal ions. As an example, the detection limit of toxic Be2+ ions, tested for the first time, was as low as 23 μM.


 Their work result has been published on Scientific Reports, 2014, 4, 4976-4983, with a name Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection. You can view the article at: http://www.nature.com/srep/2014/140515/srep04976/full/srep04976.html?message-global=remove
 

 

Figure 2: Multicolor composites based on carbon dots with polymers: L-CDs/PAM blue and white phosphors, L-CDs/PAA and L-CDs/PVP composites, L-CDs/PVP composite films using L-CDs prepared at 160 and 240°C.

 

 

 

(a) Typical PL quenching of LCD-160 in the presence of Be2+ ions; (b) Typical PL quenching of LCD-160 in the presence of Fe3+ ions; both the insets are concentration-dependent fluorescence response. (c) Performance of sensors based on prepared carbon dots: comparison of fluorescence intensities in the absence and presence of different metal ions.

 

As an important energy-saving technique, white-light-emitting diodes (W-LEDs) have been seeking for low-cost and environment-friendly substitutes for rare-earth-based expensive phosphors or Pd2+/Cd2+-based toxic quantum dots (QDs). In this work, precursors and chemical processes were elaborately designed to synthesize intercrossed carbon nanorings (IC-CNRs) with relatively pure hydroxy surface states for the first time, which enable them to overcome the aggregation-induced quenching (AIQ) effect, and to emit stable yellow-orange luminescence in both colloidal and solid states. As a direct benefit of such scarce solid luminescence from carbon nanomaterials, W-LEDs with color coordinate at (0.28, 0.27), which is close to pure white light (0.33, 0.33), were achieved through using these low-temperature-synthesized and toxic ion-free IC-CNRs as solid phosphors on blue LED chips. This work demonstrates that the design of surface states plays a crucial role in exploring new functions of fluorescent carbon nanomaterials.


Their work result has been published on Angewandte Chemie International Edition, 2014, DOI: 10.1002/ange.201406836R1, with a name Inter-crossed Carbon Nanorings with Pure Surface States as Low-cost and Environment-friendly Phosphors for White-LEDs. To view this article, you can go to the webpage: http://onlinelibrary.wiley.com/doi/10.1002/anie.201406836/abstract.

 

Although NUST Research Institute of Nano Optical and Electronic Material was founded last year, various kinds of research have been put forward. On the first half of this year, a 973 Project has been formally started; recently, this institute was awarded 5 Provincial Natural Funds and 3 National Natural Funds; Apart from the above high-level papers, another one will be published on Nano Letters (Impact Factor 12.9).

 

This research was funded by National Key Scientific and Research Project (2014CB931700-02) and Excellent Youth Fund of National Funds Committee.

 

Date: 9/15/2014

By: Jeremy