Crystal Phase Recognition and Photoluminescence Behavior of Deep Reddish-Orange Sm3+-Activated Ca9Gd(VO4)7 Nanocrystals for Modern Solid-State Lightings.

A deep reddish-orange-emitting Sm³⁺-activated vanadate-based nanocrystalline material series is developed via the solution combustion procedure. A trigonal crystal framework is formed with space group R3c (161) having unevenly designed particles with extents between 33 nm and 62 nm. Morphological aspects are examined via scanning and transmission electron microscopy (SEM and TEM). The elemental investigation is confirmed through energy-dispersive x-ray analysis (EDAX). On near-UV excitation, the luminescence spectrum presents a fair reddish-orange emission at 606-nm wavelength consistent with the electronic transition ⁴G_5/2 → ⁶H_7/2. The energy band gap is inspected via diffuse reflectance measurements. Radiative lifetime, quantum efficacy, and rates of radiation-less transformations were also examined and found to have values as 1.4914 ms, 82.84%, and 115.1 ms⁻¹ for the optimized nanosample, respectively. The CIE coordinates, and hence CCT values, lay in the reddish-orange zone of the chromaticity plot, thus finalizing their potential application in WLEDs, solid-state lighting (SSL), and other advanced optoelectronic applications. [ABSTRACT FROM AUTHOR]