Author(s): Bai, YX (Bai, Yuxing); Sun, SJ (Sun, Shaojun); Wu, LW (Wu, Liwei); Hu, TG (Hu, Tiangui); Zheng, LR (Zheng, Lirong); Wu, L (Wu, Li); Kong, YF (Kong, Yongfa); Zhang, Y (Zhang, Yi); Xu, JJ (Xu, Jingjun)

Source: JOURNAL OF MATERIALS CHEMISTRY C DOI: 10.1039/d1tc05764b Early Access Date: FEB 2022

Abstract: The widespread use of high-power LEDs has driven higher requirements for the thermal stability of luminescent materials. Here, we propose an effective synthesis strategy to achieve excellent performances of yellow-emitting phosphors LiZnPO4:xMn(2+) through modulating the contents of lattice defects. For the samples prepared in air, the characteristic transitions of Mn2+ ions are observed and the photoluminescent intensity becomes stronger with the increasing temperature until reaching a maximum at 200 degrees C. Based on electron paramagnetic resonance and defect formation energy, oxygen vacancies are responsible for the self-reduction process from Mn4+ to Mn2+ ions and anti-thermal quenching. The corresponding deep trap levels release captured electrons under thermal stimulus to the conduction band minimum, which non-radiatively relax to the lowest excited state and then withdraw back to the ground state to compensate for the luminous loss. Then, the oxygen vacancy content is optimized by a reducing atmosphere, and the high-temperature behaviours of the targeted phosphor are improved, which further verifies the positive response of properties to defect control. Finally, a fabricated WLED exhibits a good color rendering index (R-a = 89.4), demonstrating the prominent application potential of the as-prepared sample. This study opens up a new gateway for exploring novel anti-TQ optical functional materials, by virtue of the subjective structure design in self-reduction systems.

Accession Number: WOS:000761932700001

Author Identifiers:

Author Web of Science ResearcherID ORCID Number

Zhang, Yi E-4260-2010 0000-0001-9083-0611

Wu, Li E-4258-2010 0000-0001-9246-8118

ISSN: 2050-7526

eISSN: 2050-7534

Full Text: https://pubs.rsc.org/en/content/articlelanding/2022/TC/D1TC05764B