Color tunable emission from Eu3+ and Tm3+ co-doped CsPbBr3 quantum dot glass nanocomposites.

Cesium lead bromide (CsPbBr3) quantum dots (QDs) have shown great potential in the field of luminescent materials owing to their superior optical and electrical properties. However, instability and lack of multicolor emissions resulting from the intrinsic nature of CsPbBr3 QDs are still the major challenge for their commercialization. Herein, Eu3+ and Tm3+ co-doped CsPbBr3 QD glass nanocomposites (GNCs) are successfully synthesized via traditional melt-quenching followed by a heat-treatment route to obtain tunable emission in a durable host material. Tm3+ ions are doped to blue-shift the main emission peak of CsPbBr3 QDs, while Eu3+ ions are incorporated to compensate for the red deficiency. Accordingly, a tunable color emission spanning the entire visible spectrum is achieved from GNCs with a fixed composition. The incorporation of Eu3+ and Tm3+ ions promotes the crystallization of CsPbBr3 QDs in the glass host resulting in ∼100% photoluminescence quantum yield (PLQY) using a dilution method. The selected glass host has also been proven to effectively protect CsPbBr3 QDs against chemical, thermal and photo degradation. Interestingly, the selected Eu3+/Tm3+ co-doped CsPbBr3 QD GNC shows warm-white light with a low color temperature of 3692 K without utilizing any commercial phosphors. This indicates that the produced GNCs have the potential to be used as light convertor materials in multi-color LED or warm white LED applications due to their robust stability and extremely pure and tunable emission colors.

Recent progress in lanthanide-doped luminescent glasses for solid-state lighting applications-a review.

Nowadays, solid-state white light-emitting diodes (wLEDs) have attracted remarkable attention for applications in general lighting, displays and numerous electronical devices due to their eminent efficiency, longer lifetime and higher mechanical durability compared to traditional incandescent and fluorescent lights. In current commercial wLEDs, a combination of Y3Al5O12:Ce3+yellow phosphor with blue LED chip and epoxy resin is generally used to generate white light. However, there are some considerable frailties mostly originated from phosphor and resin such as, degradation upon heat, and moisture, inhomogeneous spectral distribution, and poor color rendering capability. Therefore, phosphor embedded glass-ceramics have been developed as a promising way to obtain durable solid-state lighting devices. However, in these methods, there is a greater risk of reactions between the phosphor material and the glass host. At this point, lanthanide-doped luminescent glasses have drawn great attention as a new generation phosphor and/or epoxy free white-light-emitting source owing to their favorable properties including high thermal and chemical stability, high transparency, and easy manufacturing process. This review article aims to comprehensively summarize the recent progress in singly (i.e., Dy3+, Eu2+), doubly (i.e., Dy3+/Eu3+, Dy3+/Tm3+, Dy3+/Ce3+, Ce3+/Sm3+, Ce3+/Tb3+) and triply (i.e., Ce3+/Tb3+/Mn2+, Eu3+/Tb3+/Tm3+, Ce3+/Tb3+/Eu3+, Tm3+/Tb3+/Sm3+, Ce3+/Dy3+/Eu3+, Ho3+/Tm3+/Yb3+, Er3+/Tm3+/Yb3+) lanthanide-doped glasses for solid-state lighting applications through down-shifting and up-conversion emissions. Theoretical background including energy transfer mechanisms, glass synthesis methods, radiative and colorimetric properties are given in details. Finally, various effective strategies are highlighted that minimize the critical challenges associated with lanthanides-such as providing energy transfer from quantum dots or nanoparticles to lanthanides, and doping lanthanides in low phonon energy glass-to improve the white light emission of luminescent glasses and broaden their application areas.

The synergistic effect of Er3+ and Ho3+ on temporal color tuning of upconversion emission in a glass host via a facile excitation modulation technique for anti-counterfeiting applications.

Lanthanide-doped upconversion luminescent materials are highly promising for diverse applications, e.g., solid-state lighting, volumetric displays, and anti-counterfeiting, owing to their unique optical feature of color-tunable emission under near-infrared excitation. Hence, in this study, emission color tuning of Er3+/Ho3+ ions in a fixed glass host is investigated via a facile excitation modulation technique. The upconversion emission color from green to yellowish is tuned successfully by regulating the frequency of the irradiation source. The population and depopulation rates of related transitions are investigated through time-resolved photoluminescence and Judd-Ofelt analysis in order to elucidate the proposed mechanism of color tuning. Upconversion quantum yield values are measured in the range of 0.12 to 0.17% for a better comparison of the emission properties. Additionally, thermal, and structural properties are investigated to reveal the favorable properties of the selected tellurite glass host. Ultimately, several patterns are designed and constructed by a screen-printing technique using powdered glass to demonstrate its suitability as a multicolor imaging method for anti-counterfeiting applications. The temporal color tuning of upconversion emission via a facile excitation modulation technique in a glass host clearly indicates that the proposed Er3+/Ho3+ co-doped glasses can be potentially applied in the state-of-the-art technologies, especially for anticounterfeiting purposes.