Luminescent lanthanide single atom composite materials: Tunable full-color single phosphor and applications in white LEDs

Lanthanide single-atom-based CQDs-N:Eu3+@MOF-Ln composites were reported for the time. The results of both DFT calculation and experimental characterization show that C atoms can not be replaced by Eu3+, but C atoms are more favorable for anchoring Eu3+ single-atoms. The CQDs modified by N or N/Eu3+ showed enhanced luminescence intensity. The work function, optical properties, and charge density difference were calculated. The obtained CQDs-N:Eu3+@MOF-Ln3+ composites not only have high thermal stability (up to 510 °C), but also can emit multi-color tunable emissions. Importantly, the white light emission from CQDs-N:Eu3+@MOF-Ln3+ single phosphor with excellent color quality, favorable visual performance, and adjustable color temperature can be obtained by optimizing CQDs-N:Eu3+@MOF-Ln3+. Not only the WLED devices were constructed with CQDs-N:Eu3+ and MOF-Ln3+, but also the single CQDs-N:Eu3+@MOF-Ln3+ phosphor-based warm WLED devices were realized, and achieves superior color quality (a CRI of 95) and ideal correlated color temperature (a CCT of 4035 K).