Efficient near-infrared phosphors discovered by parametrizing the Eu(II) 5d-to-4f energy gap

Inorganic materials with rare-earth activators (e.g., Ce, Eu) exhibit broad 5d-to-4f emission spectra characterized by a strong host material dependency. Despite extensive research, the development of an efficient and near-infrared (NIR) 5d-to-4f emission remains elusive. Herein, we introduce key descriptors of the Eu(II)-host interactions and predict the in-crystal 5d-to-4f energy gap with a root mean-square error of ca. 0.03 eV (7.0 nm). By incorporating this luminescence predictor into a high-throughput screening of 223 nitride materials in the Inorganic Crystal Structure Database, we identify and experimentally validate (Sr,Ba)(3)Li4Si2N6:Eu(II) with NIR emissions of lambda(em) = 800 ~ 830 nm and high quantum efficiencies (QEs) of 30% ~ 40%, leading to an NIR light power -33 superior to prevailing NIR emitters. The ultralong lambda(em) and high QE stem from a coordinated energy transfer and an optimized electronic delocalization around Eu(II). This work provides a cost-efficient computational approach for discovering phosphors with desired emissions.

Automated summary

In this study, the key descriptors of Eu(II)-host interactions were introduced to predict the 5d-to-4f energy gap in the crystal, and a high-throughput screening of 223 nitride materials led to the discovery and experimental validation of (Sr,Ba)(3)Li4Si2N6:Eu(II) with near-infrared emissions and high quantum efficiencies. This work provides a cost-efficient computational approach for discovering phosphors with desired emissions.