Abstract
A strategy for fabricating bendable AlGaInP light emitting diode (LED) arrays is presented in this paper. Sample LED arrays with 8 × 8 pixels were fabricated and subjected to bending. Bending only weakly affected the light output power and the current–voltage characteristics of the arrays. LED arrays suffer from a thermal problem owing to the energy loss during the electrical-to-optical energy conversion. We have designed a three-dimensional heat conduction model for analyzing the effect of the polymer substrate, the configuration of pixels, and the micro-structure on heat dissipation in bendable LED arrays. Thermal conductivity of the polymer substrate critically affected the heat dissipation, suggesting that the substrate thickness should be in the 500–1000 μm range. A larger pixel distance yielded more distributed heat sources and more uniform temperature distribution. Micro-structured polymer substrates yielded lower temperature, especially for the fins array micro-structure. Based on enhancing the polymer’s thermal conductivity and distributing LED pixels, optimizing the substrate’s micro-structure is an effective method to improve heat dissipation in bendable LED arrays. Optimized heat dissipation could effectively reduce heat accumulation in LED arrays and alleviate an increase in the junction temperature, allowing to increase the output power of the device.
Highlights
Flexible and conformable optoelectronic devices have recently received significant attention and have been the subject of intense investigations.[1,2] Thin epitaxial layers of inorganic semiconductors have been commonly grown on thick and rigid substrates, significantly reducing their mechanical deformability
In establishing the model to describe heat dissipation in bendable light emitting diode (LED) arrays, some assumptions are made throughout the analysis as following:25,26 1) Heat is generated only in the LED and no input power density in other regions; 2) Each layer is thermally homogeneous and isotropic; 3) The thermal properties of Each layer are independent of temperature; 4) The layers of the structure are in intimate contact with each other so that the thermal contact resistance is zero
We presented fabrication of bendable vertical AlGaInP-LED arrays
Summary
The effect of self-heating can be alleviated by improving the device’s energy efficiency, for example by modifying its epitaxial structure, by improving the current spread, or by enhancing its light extraction efficiency.[15,16,17,18,19] Besides, it is a necessary supplement for thermal management to improve heat dissipation as the limitation of nature properties of materials and processing techniques. We describe the fabrication process of bendable AlGaInP micro-LED arrays. Based on the analysis of energy loss in LED, the heat power density of single pixel was calculated by the test results of light output power and current–voltage characteristics. We have investigated the dependence of the heat dissipation in LED arrays on factors such as the thermal conductivity and thickness of the polymer substrate, spatial distribution of LEDs, and device micro-structure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
