Improvement of Temperature and Optical Power of an LED by Using Microfluidic Circulating System of Graphene Solution.

Yung-Chiang Chung,Shih-Hao Lin,Han-Hsuan Chung

doi:10.3390/nano11071719

Abstract

Electric devices have evolved to become smaller, more multifunctional, and increasingly integrated. When the total volume of a device is reduced, insufficient heat dissipation may result in device failure. A microfluidic channel with a graphene solution may replace solid conductors for simultaneously supplying energy and dissipating heat in a light emitting diode (LED). In this study, an automated recycling system using a graphene solution was designed that reduces the necessity of manual operation. The optical power and temperature of an LED using this system was measured for an extended period and compared with the performance of a solid conductor. The temperature difference of the LED bottom using the solid and liquid conductors reached 25 °C. The optical power of the LED using the liquid conductor was higher than that of the solid conductor after 120 min of LED operation. When the flow rate was increased, the temperature difference of the LED bottom between initial and 480 min was lower, and the optical power of the LED was higher. This result was attributable to the higher temperature of the LED with the solid conductor. Moreover, the optical/electric power transfer rate of the liquid conductor was higher than that of the solid conductor after 120 min of LED operation, and the difference increased over time.

Highlights

The results indicated that the voltage of the graphene solution–conductor light emitting diode (LED) was 2.8 V when the voltage of the power supply was 5.5 V
This study proposes an automated graphene-solution circulating system that can efficiently dissipate heat and conduct electricity
The temperature and optical power of an LED were measured over an extended period

Summary

Introduction

Heat dissipation and electrical conduction are critical considerations in the operation of an integrated circuit device. Several heat dissipation methods, such as the use of microfluidic devices, are employed in electric systems. Researchers have considered using nanofluids for cooling electric devices [1,2]. Studies have proposed a thermal contact liquid cooling system [3] as well as a technique for cooling photovoltaic cell systems through the use of rotating magnetic fields and ferrofluids [4]. A related study used a system combining liquid cooling and composite phase change material cooling to dissipate the heat generated in a battery [5]. Research has revealed various cooling methods for electric devices [8,9,10]

Methods

Results

Conclusion