One‐Pot Exfoliation of Graphitic C3N4 Quantum Dots for Blue QLEDs by Methylamine Intercalation. Issue 44 (12th September 2019)

• Record Type: Journal Article
• Authors: He, Xingchen; Liu, Yanliang; Butch, Christopher J.; Lee, Bo Ram; Guo, Feng; Wu, Jiangxiao; Wang, Ziyang; Lu, Qian; Jeong, Jung Hyun; Wang, Yiqing; Park, Sung Heum
• Is Part Of: Small. Volume 15:Issue 44(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-12
• Subjects: graphitic carbon nitride -- hydrothermal exfoliation -- metal‐free semiconductors -- quantum dot light‐emitting diodes; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201902735
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Here, a simplified synthesis of graphitic carbon nitride quantum dots (g‐C3 N4 ‐QDs) with improved solution and electroluminescent properties using a one‐pot methylamine intercalation–stripping method (OMIM) to hydrothermally exfoliate QDs from bulk graphitic carbon nitride (g‐C3 N4 ) is presented. The quantum dots synthesized by this method retain the blue photoluminescence with extremely high fluorescent quantum yield (47.0%). As compared to previously reported quantum dots, the g‐C3 N4 ‐QDs synthesized herein have lower polydispersity and improved solution stability due to high absolute zeta‐potential (−41.23 mV), which combine to create a much more tractable material for solution processed thin film fabrication. Spin coating of these QDs yields uniform films with full coverage and low surface roughness ideal for quantum dot light‐emitting diode (QLED) fabrication. When incorporated into a functional QLED with OMIM g‐C3 N4 ‐QDs as the emitting layer, the LED demonstrates ≈60× higher luminance (605 vs 11 Cd m −2 ) at lower operating voltage (9 vs 21 V), as compared to the previously reported first generation g‐C3 N4 QLEDs, though further work is needed to improve device stability. Abstract : Graphitic C3 N4 quantum dots (QDs) are synthesized by a one‐pot methylamine intercalation–stripping method; spin coating of these QDs yields uniform films with full coverage and low surface roughness, ideal for QD light‐emitting diode (QLED) fabrication. This QLED exhibits satisfactory device performance with luminance of 605 cd m −2 at 9 V and maximum current efficiency of 0.09 cd A −1 .