Gram‐Scale Synthesis of 41% Efficient Single‐Component White‐Light‐Emissive Carbonized Polymer Dots with Hybrid Fluorescence/Phosphorescence for White Light‐Emitting Diodes. Issue 4 (16th January 2020)

• Record Type: Journal Article
• Authors: Wang, Zifei; Liu, Yang; Zhen, Shijie; Li, Xiaoxi; Zhang, Weiguang; Sun, Xun; Xu, Baoyuan; Wang, Xue; Gao, Zhenhua; Meng, Xiangeng
• Is Part Of: Advanced science. Volume 7:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-16
• Subjects: carbonized polymer dots -- high quantum yield -- hybrid fluorescence/phosphorescence -- white light emission -- white light‐emitting diodes; Science -- Periodicals; 505
• DOI: 10.1002/advs.201902688
• Languages: English
• ISSNs: 2198-3844

Abstract

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. Abstract : Gram‐scale single‐component white‐light‐emissive carbonized polymer dots (SW‐CPDs) containing two emission centers of blue fluorescence and green room‐temperature phosphorescence with an overall quantum yield up to 41% are successfully prepared. A white light‐emitting diode (WLED) is fabricated by employing the SW‐CPDs with a commercial UV‐LED chip. This work provides an important step toward development of high‐performance CPDs‐based WLEDs.