Abstract
Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) hold promising potential as next-generation compact, portable, and intelligent NIR light sources. Nonetheless, the lack of high-performance broadband NIR phosphors with an emission peak beyond 900 nm has severely hindered the development and widespread application of NIR pc-LEDs. This study presents a strategy for precise control of energy-state coupling in spinel solid solutions composed of MgxZn1-xGa2O4 to tune the NIR emissions of Cr3+ activators. By combining crystal field engineering and heavy doping, the Cr3+-Cr3+ ion pair emission from the 4T2 state is unlocked, giving rise to unusual broadband NIR emission spanning 650 and 1400 nm with an emission maximum of 913 nm and a full width at half-maximum (fwhm) of 213 nm. Under an optimal Mg/Zn ratio of 4:1, the sample achieves record-breaking performance, including high internal and external quantum efficiency (IQE = 83.9% and EQE = 35.7%) and excellent thermal stability (I423 K/I298 K = 75.8%). Encapsulating the as-obtained phosphors into prototype pc-LEDs yields an overwhelming NIR output power of 124.2 mW at a driving current of 840 mA and a photoelectric conversion efficiency (PCE) of 10.5% at 30 mA, rendering high performance in NIR imaging applications. © 2024 American Chemical Society.
| Original language | English |
|---|---|
| Pages (from-to) | 30185-30195 |
| Number of pages | 11 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 16 |
| Issue number | 23 |
| Online published | 31 May 2024 |
| DOIs | |
| Publication status | Published - 12 Jun 2024 |
Funding
This work was supported by the National Natural Science Foundation of China (nos. 51802045 and 51972065) and Guangzhou Basic and Applied Basic Research Project (202102020871). We also would like to thank Analysis and Test Center of Guangdong University of Technology for the SEM and XPS analysis. F.W. acknowledges the Research Grants Council of Hong Kong for a Research Fellowship Award (grant no. RFS2021-1S03).
Research Keywords
- energy-state coupling
- heavy doping
- ion pair
- NIR imaging
- pc-LED
Publisher's Copyright Statement
- COPYRIGHT TERMS OF DEPOSITED POSTPRINT FILE: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.4c03419.