Gram‐Scale Synthesis of 41% Efficient Single‐Component White‐Light‐Emissive Carbonized Polymer Dots with Hybrid Fluorescence/Phosphorescence for White Light‐Emitting Diodes

Abstract

Fluorescent carbon dots (CDs) are compelling optical emitters to construct white light‐emitting diodes (WLEDs). However, it remains a challenge to achieve large‐scale and highly efficient single‐component white‐light‐emissive CDs suitable for WLED applications. Herein, a low cost, fast processable, environmentally friendly, and one‐step synthetic approach is developed for the preparation of gram‐scale and highly efficient single‐component white‐light‐emissive carbonized polymer dots (SW‐CPDs). It is revealed that hybrid fluorescence/phosphorescence components cooperatively contribute to the emergence of white light emission. The SW‐CPDs exhibit a record quantum yield (QY) of ≈41% for the white light emission observed in solid‐state CD systems, while the QY of the phosphorescence is ≈23% under ambient conditions. Heavy doping of N and P elements as well as presence of covalently cross‐linked polymer frameworks is suggested to account for the emergence of hybrid fluorescence/phosphorescence, which is supported by the experimental results and theoretical calculations. A WLED is fabricated by applying the SW‐CPDs on an UV‐LED chip, showing favorable white‐light‐emitting characteristics with a high luminous efficacy of 18.7 lm W−1 that is comparable to that of state‐of‐the‐art WLEDs reported before.

Photo-induced ultralong phosphorescence of carbon dots for thermally sensitive dynamic patterning

“…These emerging luminescent nano-dots are small-sized (<10 nm), mass-producible, compatible with organic materials and optically robust. [20][21][22][23] Furthermore, the incorporation of CDs with polymers has produced a series of composite lms with reliable URTP long aerglow performance, [24][25][26][27][28][29] enriching the library of transparent and exible URTP materials. It was recently reported that CDs in polymer matrices can serve not only as URTP emitters, but also as reactive centers that alter the regional environments in the materials, facilitating dynamic URTP performance.…”

Rare Earth‐Free Luminescent Materials for WLEDs: Recent Progress and Perspectives

“…[58] Wang et al prepared a carbonized polymer dot with dual emission of blue fluorescence and yellow-green phosphorescence, with a total PLQY of up to 41% (Figure 4a,b). [59] Recently, Wu et al prepared white light-emitting graphene QDs with a high PLQY of 34% using 1,5-diaminonaphthalene (DAN) as the precursor, trichloromethane (TCM) as the Cl source, and ethanol as the solvent, by a solvothermal molecular fusion method. This material showed excitation-dependent fluorescence emission and room temperature phosphorescence in the solid state.…”

“…The previous parts were reproduced under the terms and conditions of the CC BY License. [59] Copyright 2020, The Authors. Published by Wiley-VCH.…”

The Behavior of Carbonized Polymer Dots at the Nano‐Bio Interface and Their Luminescent Mechanism: A Physical Chemistry Perspective

“…[ 9 ] The CPDs possess a polymer/carbon hybrid structure comprising of shells with abundant functional groups/polymer chains and carbon cores with high cross‐linking or slight graphitization. [ 10 ] Herein, CPDs were used to refer luminescent carbon nanomaterials in this review. Recently, an emerging perspective in the field of nanomaterials based nanomedicine is that wide space between novel advances and clinical translation of therapeutic nanomaterials is derived from incomplete understanding of nano‐bio interactions.…”