Chromium Cluster Luminescence: Advancing Near‐Infrared Light‐Emitting Diode Design for Next‐Generation Broadband Compact Light Sources
Veeramani Rajendran, Chih‐Yu Chang, Ming‐Hsuan Huang, Kuan‐Chun Chen, Wen‐Tse Huang, Mikołaj Kamiński, Tadeusz Leśniewski, Sebastian Mahlik, Grzegorz Leniec, Kuang‐Mao Lu, Da‐Hua Wei, Ho Chang, Ru‐Shi Liu
Abstract
Abstract In modern technology devices, an energy‐saving miniature near‐infrared (NIR) light source plays a critical role in non‐destructive, non‐invasive sensing applications and further advancement of technology. This paper reports the broadband NIR luminescence of Cr 3+ clusters for designing phosphor‐converted NIR light‐emitting diodes as an alternative to typical isolated Cr 3+ centers and Cr 3+ ion pairs. Here, Cr 3+ clusters form in the intermediate spinel structure of MgGa 2 O 4 by utilizing the long‐chain edge‐shared octahedral dimers with the shortest bond distance between Cr 3+ cations. Electron paramagnetic and magnetometry measurements confirm the isolated Cr 3+ and Cr 3+ clusters, resulting in NIR luminescence with three distinct emission centers. The formation of Cr 3+ clusters in MgGa 2 O 4 ensures stable internal quantum efficiency (≈94%), full‐width‐half‐maximum (248 nm), thermal stability (87%), and a radiant flux of ≈17.66 mW. This work offers a promising approach to NIR phosphor design and enhances the understanding of luminescence mechanisms in spinel and related structures.