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ZnGa2Se4, a nonlinear material with wide mid infrared transparency and good thermomechanical properties
摘要： During the last decades, mid-infrared (3–12 μm) laser sources using crystals with nonlinear optical properties have attracted a particular attention due to their potential applications in different fields such as optical counter-measures and remote chemical sensing. As transparency of common oxide crystals is limited to about 4 μm, many researches have been focused on chalcopyrite compounds because of their wide transparency in the mid-IR range and their strong nonlinear optical coefficients. There is a need of such crystals able to convert efficiently the near infrared wavelengths from commercially available lasers into wavelengths higher than 5 μm through Optical Parametric Oscillators (OPO) systems. This paper presents a new compound: ZnGa2Se4 (ZGSe). Measurements made on dense polycrystals show a high thermal conductivity value in comparison with other selenides (2.9 W m?1 K?1), a wide transparency from visible to beyond the band III of the mid IR (0.6 μm–17 μm) and a coefficient of thermal expansion inferior to 10?5 K?1. These results are very encouraging and improvements of the growth process are now undertaken to obtain single crystals with the required optical quality.
关键词： Optical materials and properties,ZnGa2Se4,Crystal growth,Thermomechanical properties
更新于2025-11-19 16:56:35
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Flexible but Mechanically Robust Hazy Quantum Dot/Glass Fiber Reinforced Film for Efficiently Luminescent Surface Light Source
摘要： Color conversion films with haze have aroused interest for use in surface light sources for display and lighting applications. Surface patterning or addition of light scattering particles to the color-conversion film induces haze and consequently, improves the photoluminescence (PL) extraction. Herein, a CdSe/CdZnS quantum dots (QDs)-embedded glass fiber reinforced siloxane hybrid (QD-GFRH) film with high haze value is demonstrated, originating from refractive index mismatch between glass fiber and methacrylate-phenyl functionalized siloxane matrix. The hazy QD-GFRH film shows a twofold improvement in PL extraction, as well as robust mechanical properties, such as low thermal expansion (13 × 10?6 K?1) and high deformation resistance (E = 11.8 GPa), compared to conventional polymers. Because QDs are chemically dispersed inside the film by covalent crosslinking with siloxane matrix, the QD-GFRH film exhibits long-term (30 days) thermal and chemical stability against heat and moisture conditions [85 °C/5% relative humidity (RH), and 85 °C/85% RH]. Furthermore, the yellow photoemissive QD-GFRH film, with a smooth surface and large scale (A4 size, 210 mm × 297 mm size), is applied as a color-conversion film on a blue light-emitting diode and it covers a large color gamut (107% relative to National Television System Committee).
关键词： light-converting films,quantum dots,haze control,thermomechanical properties,glass fiber reinforced films,surface light sources
更新于2025-09-23 15:19:57