Yellow emissive carbon dots with quantum yield up to 68.6% from manganese ions

The development of high quantum yield (QY) carbon dots (CDs) is a key requirement for applications. However, how to engineer well-defined absorption band in visible region is a critical challenge to obtaining highly efficient long wavelength emissive CDs. In this work, the strategies of solvent-tuning absorption band and manganese ions-enhancing optical performance are introduced to prepare yellow emissive CDs. The utilization of toluene as solvent is a basis for achieving absorption band at 435 nm and realizing yellow emissive CDs with QY of 46%. Addition of manganese ions increase the degree of conjugated sp(2)-domians and surface states, further enhancing QY up to 68.6%. Using the yellow emissive CDs, a UV-pumped light-emitting diode (LED) was fabricated based on a 395 nm LED chip. The LED shows warm light with correlated color temperature (CCT) of 1596 K and color purity of 99%. This work provides a new insight for the development of high-quality CDs with versatile properties in pursuit of promising applications. (C) 2018 Elsevier Ltd. All rights reserved.