Carbon Dots for Electroluminescent Light‐Emitting Diodes: Recent Progress and Future Prospects

Abstract

Carbon dots (CDs), as emerging carbon nanomaterials, have been regarded as promising alternatives for electroluminescent light‐emitting diodes (LEDs) owing to their distinct characteristics, such as low toxicity, tuneable photoluminescence, and good photostability. In the last few years, despite remarkable progress achieved in CD‐based LEDs, their device performance is still inferior to that of well‐developed organic, heavy‐metal‐based QDs, and perovskite LEDs. To better exploit LED applications and boost device performance, in this review, a comprehensive overview of currently explored CDs is presented, focusing on their key optical characteristics, which are closely related to the structural design of CDs from their carbon core to surface modifications, and to macroscopic structural engineering, including the embedding of CDs in the matrix or spatial arrangement of CDs. The design of CD‐based LEDs for display and lighting applications based on the fluorescence, phosphorescence, and delayed fluorescence emission of CDs is also highlighted. Finally, it is concluded with a discussion regarding the key challenges and plausible prospects in this field. It is hoped that this review inspires more extensive research on CDs from a new perspective and promotes practical applications of CD‐based LEDs in multiple directions of current and future research.

Visible Light‐Activated Ultralong‐Lived Triplet Excitons of Carbon Dots for White‐Light Manipulated Anti‐Counterfeiting

“…Additionally, the high-resolution TEM (HRTEM) images reveal a highly crystalline carbon core with an evident lattice distance of 0.21 nm, which corresponds to the (100) crystallographic facets of graphite carbon. [27][28][29][30] The particle size of N-CDs is also measured using atomic force microscopy (AFM) (Figure 3b), and the average topographic height is found to be 2.62 nm, which is consistent with the TEM characterization. [31,32] The X-ray powder diffraction (XRD) patterns of N-CDs (Figure 3c) exhibit a strong and broad characteristic peak at approximately 26.5°, which corresponds to the graphitic structure with an interlayer spacing of (002).…”

The emergence and prospects of carbon dots with solid-state photoluminescence for light-emitting diodes

“…13,14 In particular, the characteristic broadband emission and narrow bandwidth can be used for white LEDs (WLEDs) and high color-purity multicolored LEDs, respectively, which opens up great prospects for CDs in next-generation lighting and displays. 15,16…”

Photoluminescence mechanism of red emissive carbon dots from a diaminobenzoic acid isomer

“…Carbon dots (CDs), a class of quasi-spherical nanoparticles, owing to their distinctive optical and electrical properties, provide a new perspective for carbon-based luminescent materials since their accidental discovery in 2004. 1–8 In particular, red emissive CDs (RCDs) with low cytotoxicity, weak auto-fluorescence, and deep-tissue penetration have recently shone as promising imaging agents in biomedical applications. 9–16 Unfortunately, the controversial photoluminescence (PL) origin still hinders the controllable design and preparation of efficient RCDs.…”