Ultrahigh Quantum Efficiency Near-Infrared-II Emission Achieved by Cr<sup>3+</sup> Clusters to Ni<sup>2+</sup> Energy Transfer
Chih‐Yu Chang, Ming-Hsuan Huang, Kuan‐Chun Chen, Wen‐Tse Huang, Mikołaj Kamiński, Natalia Majewska, Tomasz Klimczuk, Jia-Hao Chen, Ding‐Hua Cherng, Kuang‐Mao Lu, Wei Kong Pang, Vanessa K. Peterson, Sebastian Mahlik, Grzegorz Leniec, Ru‐Shi Liu
Abstract
High Resolution Image Download MS PowerPoint Slide Increasing demand for near-infrared-II (NIR-II) light sources requires improved NIR-II phosphors. We present a series of phosphors codoped with Cr 3+ and Ni 2+ that possess NIR-II emission with an unprecedented internal quantum efficiency (IQE) of 97.4%. Our study reveals an energy transfer mechanism involving clusters of Cr 3+ where luminescent centers are closely matched in energy and where the Ni 2+ emission intensity can be tuned through sintering temperature. The profound electron paramagnetic resonance (EPR) studies disclose the interaction between Cr 3+ clusters and Cr 3+ –Ni 2+ pairs, further proving the cause of such a high IQE and the significance of Cr 3+ clusters. This work provides promising pathways for the development of NIR-II light-emitting diodes with outstanding efficiency by suggesting a new energy transfer source of Cr 3+ .