Authors : J. Shivakumara; H. M. Dayananda; G. Chandrashekaraiah

Volume/Issue : Volume 11 - 2026, Issue 8 - August

Google Scholar : https://tinyurl.com/4ajcnsp3

DOI : https://doi.org/10.38124/ijisrt/26aug1420

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : Red-emitting phosphors are essential components of modern solid-state lighting, wide-gamut displays, laser lighting, optical sensors and emerging photonic technologies. The development of efficient red phosphors has received considerable attention because conventional red emitters often suffer from insufficient absorption in the blue spectral region, thermal quenching, broad emission or poor chemical stability. This review summarizes recent progress in inorganic red-emitting phosphors activated mainly by Eu³⁺, Eu²⁺ and Mn⁴⁺ ions, with emphasis on photoluminescence characteristics and suitability for blue-light-excited white light-emitting diodes (WLEDs) and display applications. Eu³⁺ phosphors generally provide sharp and highly colour-pure red emission near 610–620 nm, whereas Eu²⁺ offers broad and compositionally tunable emission extending into the deep-red region. Mn⁴⁺-activated fluoride phosphors exhibit narrow-band red emission and are particularly attractive for wide-colour-gamut displays. Representative materials are compared in terms of excitation wavelength, emission maximum, quantum efficiency, decay lifetime and thermal stability. Direct comparison is complicated by differences between internal quantum efficiency, external quantum efficiency and quantum yield. Recent results demonstrate quantum efficiencies exceeding 90% for selected systems, although the measurement conditions must always be specified. Remaining challenges include thermal quenching, moisture sensitivity, synthesis complexity, spectral reabsorption and cost. Future development is expected to focus on host-lattice engineering, defect control, surface protection, large-crystal growth and computationally assisted phosphor discovery.

Keywords : Eu²⁺ Phosphor; Eu³⁺ Phosphor; Mn⁴⁺ Phosphor; Red Emission; Solid-State Lighting; Thermal Stability; Quantum Efficiency; Wleds.

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