Near-infrared (NIR) phosphors are enticing photoluminescent materials with applications in light-emitting diodes for spectroscopy. These phosphors have two types of emissions: Type I has a Gaussian curve, whereas Type II is similar to a plateau. Both emissions have industrial uses, but uncertain remains regarding which type is ideal. In this review, we compare two distinct NIR phosphors with Type I and Type II emissions in terms of their structure, crystal field, and emission profile and then provide our perspective on what the ideal emission must be.
De Guzman, G. N. A., Fang, M. H., Liang, C. H., Bao, Z., Hu, S. F., & Liu, R. S. (2020). Near-infrared phosphors and their full potential: A review on practical applications and future perspectives. Journal of Luminescence, 219. https://doi.org/10.1016/j.jlumin.2019.116944