Lanthanide-Based Deep Red-Emitting Phosphors for Hybrid White LEDs and Plant Growth Applications

Abstract

Phosphor based white LEDs (w-LED) have accomplished more consideration in modern technology to save energy and are widely used for versatile applications. A crucial and essential component in increasing the overall efficiency of the w-LED is the oxide based narrow band red emitting phosphor. In this regard, a series of Eu3+ -activated Na2La4(WO4)7 (NLW) red emitting phosphors were synthesized employing a solid-state approach, and their optical characteristics were thoroughly investigated. All compositions crystallize in a tetragonal structure with I41/a space group. Sharp red emission was exhibited by all the NLW:Eu3+ phosphors ∼616 nm owing to the ED transition (5D0→7 F2), under the excitation of 394 nm and observed concentration quenching when x = 0.8. In addition, the color purity and IQE of NLW:0.8Eu3+ phosphor were found to be 96.79% and 83.76%, respectively. The thermal stability of the phosphor is found to be 69.75% at 423 K according to a temperaturedependent PL analysis. Practical utility of the synthesized phosphors were determined by fabricating red and white LEDs. Moreover, latent fingerprint application is possible with this Eu3+ -doped red phosphors. Additionally, red/deep red LEDs were made for plant growth application by synthesizing simultaneous activation of Sm3+ and Eu3+ in NLW phosphors. These results indicated that the synthesized phosphors would be good phosphors for applications related to w-LED, latent fingerprint, and plant growth.