Photo-and Electroluminescence from Nitrogen-Doped and Nitrogen-Sulfur Codoped Graphene Quantum Dots
Photo-and Electroluminescence from Nitrogen-Doped and Nitrogen-Sulfur Codoped Graphene Quantum Dots
复制标题
DOI：
10.1002/adfm.201804337
复制
发表时间：
2018-10-17
影响因子：
19
通讯作者：
Naumov, Anton V.
中科院分区：
文献类型：
--
作者：
Hasan, Md Tanvir;Gonzalez-Rodriguez, Roberto;Naumov, Anton V.
与无机量子点相比，有机量子点通常表现出较低的荧光效率，而且合成复杂。在这里，我们开发了氮掺杂(N-GQds)和氮硫共掺杂(NS-GQds)石墨烯量子点，这些量子点具有高产量的可见光和近红外发射，它们是以单一的氨基葡萄糖-盐酸盐为起始原料(用于NS-GQD的硫脲前体)通过一步微波辅助水热技术合成的。合成的N-GQD和NS-GQD具有良好的分散性(平均尺寸分别为5.50和3.90 nm)，具有较高的结晶度和明显的G带。它们由氨基葡萄糖自下而上组装而成，含有胺键和各种含氧官能团，通过傅立叶变换红外光谱对NS-GQD进行了硫含量约为2%的表征。合成过程允许改变它们的大小和带隙。与其他基于石墨烯的量子点不同，这些量子点在可见光和近红外波段都显示出明亮、稳定的荧光，量子产率高达60%。激发相关的可见荧光是由大小相关的带隙引起的，近红外发射可能来自发射缺陷态/它们的排列。利用这些GQD的有利性质来开发用于有机发光器件的激子复合层，在可见光下既表现出光致发光又表现出电致发光。通过一步可伸缩合成得到的发光N-GQD和NS-GQD是一种很有前途的新型有机光电子学材料。
As opposed to inorganic counterparts, organic quantum dots often exhibit lower fluorescence efficiencies and are complex to synthesize. Here we develop nitrogen-doped (N-GQDs) and nitrogen-sulfur codoped (NS-GQDs) graphene quantum dots exhibiting high-yield visible and near-IR emission that are synthesized via a single-step microwave-assisted hydrothermal technique with a single glucosamine-HCl starting material (thiourea precursor used for NS-GQDs). As-synthesized N-GQDs and NS-GQDs are well-dispersed (average sizes of 5.50 and 3.90 nm) with high crystallinity and pronounced G-band. Formed by the bottom-up assembly of glucosamine, they contain amine linkage and a variety of oxygen-containing functional groups assessed by Fourier-transform infrared spectroscopy with approximate to 2% sulfur for NS-GQDs. The synthetic procedure allows varying their size and the bandgap. Unlike other graphene-based quantum dots, these GQDs exhibit bright, stable fluorescence both in the visible and near-IR with high quantum yields of up to 60%. Excitation-dependent visible fluorescence is attributed to size-dependent bandgaps, with near-IR emission potentially arising from the emissive defect states/their arrangements. Advantageous properties of these GQDs are utilized to develop exciton recombination layer for organic light-emitting devices exhibiting both photoluminescence and electroluminescence in the visible. Produced by ecofriendly one-step scalable synthesis brightly-emissive N-GQDs and NS-GQDs become a promising material for novel organic optoelectronics.