Abstract
The aging of phosphor/silicone composites plays an important role in the optical and mechanical properties of high-power light emitting diode (LED) packaging. In this paper, the accelerated aging experiments under high temperature, high humidity and sulfur conditions were carried out on (Ca,Sr)AlSiN3:Eu2+ phosphor/silicone composites used in high color-rendering LED packaging, and their aging mechanisms under different conditions were analyzed through the emission spectrum and tensile behavior measurements, combined with the results of Fourier Transform infrared (FTIR) spectroscopy. The experimental results show that: (1) The coupling effects of thermal-humidity-sulfur made the phosphor/silicone composite degrade and become brittle as a result of hydrolysis of phosphor and chemical reaction with sulfur, which might influence the service life of LED packaging. (2) The interfacial cohesion model was subsequently employed to simulate the tension behavior and interfacial cracking of the phosphor/silicone composites. (3) The simulation results indicate that the shape and distribution of phosphor particles great affected the mechanical properties and interfacial cracking position of composites, and the cohesion between the interfaces can well explain the evolution of their mechanical properties after aging.
Published Version
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