Inorganic Light-Emitting Diodes (ILEDs) are attractive for broad classes of applications in solid-state lighting, optical communication, and optogenetics due to their high efficiency, fast response, and long lifetime etc. The recently developed flexible ILED enables lots of novel applications especially in bio-integrated therapeutic devices that could be integrated with soft tissues well because they are able to be deformed like a rubber band. The low thermal conductivity of the elastomeric substrate in flexible ILEDs, which is about 3 orders of magnitude lower than that of the typical substrate for conventional ILEDs, imposes critical challenges in the thermal management. In this paper, an analytical model, validated by three dimensional finite element simulations, is developed to study the thermal properties of microscale inorganic LEDs with a rectangular shape. The temperature rise of ILED is derived analytically and agrees well with finite element simulations. A simple scaling law for the ILED temperature rise is then established in terms of the material and geometrical parameters. It is found that the ILED temperature rise depends on only 4 non-dimensional parameters. These results pave the basis for thermal management of flexible ILEDs and provide design guidelines for minimizing their adverse thermal effects on the performance as well as in applications.
北京航空航天大学国际交叉研究院资助项目
国家自然科学基金(11502009)
国家重点基础研究发展计划(2015CB351900)
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图1
μ-ILED的四分之一结构示意图
图2
μ-ILED温升随边长的变化规律
图3
图4
无量纲μ-ILED温升
图5
无量纲μ-ILED温升
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