Synthesis of Longer‐Wavelength‐Emissive Carbon Quantum Dots for WLEDs and Investigation of Their Photoluminescence Properties

Abstract

The synthesis of highly fluorescent longer wavelength emissive carbon quantum dots (CQDs) is still a great challenge as well as an important issue, hindering its application in white light emitting diode (WLED). Herein, we have demonstrated a simple one‐pot solvothermal route for the synthesis of nitrogen and sulphur co‐doped CQDs using pyromellitic acid (PA), diethylenetriamine (DETA) and thiourea. At the specific molar ratio of the precursors, the orange color emissive CQDs (O‐CQDs) are synthesized and possess longer wavelength emission (611 nm). Additionally, O‐CQDs exhibits temperature and pH dependent photoluminescence (PL) properties. The O‐CQDs shows color correlated temperature (CCT) of 1745 K with high color purity of 98%. Simultaneously, as‐synthesized nitrogen and sulphur co‐doped CQDs shows concentration‐dependent PL properties, which display not only the brightness with stable orange color but also possess range of multicolour emission at different PL excitation. Solid host matrix of O‐CQDs is fabricated with poly‐(methyl methacrylate) (PMMA) chloroform solution and orange emissive property is investigated by wrapping the film over LED (InGaN) bulb. These studies will open up new opportunities to explore the tunable optical properties of carbon quantum dots and its applications in WLED devices.

Effect of Solvent-Derived Highly Luminescent Multicolor Carbon Dots for White-Light-Emitting Diodes and Water Detection

“…Fortunately, in recent years, researchers have focused on developing longer-wavelength-emitting CDs, and quite a few exciting results have been reported. 15,16 Now, many strategies have reported to synthesize the longer-wavelength as well as multicolor emissive CDs such as the solvatochromic effect, pH effect, heteroatom doping, surface state, and size control. Among the different approaches, the solvent effect is one of the substantial fields of research.…”

“…Carbon dots (CDs) have attracted attention as promising nanomaterials for light-emitting diodes (LEDs), , photocatalysis, sensors, , imaging, , and drug delivery , in the last few years because of their luminescence properties, high stability, low cost, low toxicity, exceptional biocompatibility, and inexpensive precursors. − At an initial stage, most of the reported CDs emitted shorter wavelengths under the optimum excitation that is either blue or green luminescence, , which restricts their wider applications in LEDs and biological imaging. Fortunately, in recent years, researchers have focused on developing longer-wavelength-emitting CDs, and quite a few exciting results have been reported. , Now, many strategies have reported to synthesize the longer-wavelength as well as multicolor emissive CDs such as the solvatochromic effect, pH effect, heteroatom doping, surface state, and size control. Among the different approaches, the solvent effect is one of the substantial fields of research.…”

High-performance thermoplastic polyurethane elastomer/carbon dots bulk nanocomposites with strong luminescence

“…This indicates that the emission is originated from the transition of an absorption band at 399 nm. 24,25 The solid-state CDs exhibit bright blue fluorescence as shown in the inset of Figure 2(c), and the absolute PL QY can reach 20%.…”

Color Conversion Light-Emitting Diodes Based on Carbon Dots: A Review

“…The introduction of the N- and S-doped states, starting from the appropriate precursors, allowed Kumari et al to prepare orange emissive CDs, and, more generally, multicolor emissive CDs, which were efficiently used for the fabrication of orange and white LEDs [ 116 ].…”