Research on the Optoelectronic and Thermal Characteristics of High-Power-Density LEDs

High-power-density LED devices have emerged as a prominent focus in current research and industrial development, largely due to their role in advancing LED lighting technologies. At high power and high current, the structure and area of the thermoelectrically separated copper substrate connected to the LEDs significantly influence the device’s optoelectronic performance, yet detailed studies in this area remain limited. To address this issue, blue and white LED devices with a maximum power rating of 400 W were fabricated and soldered onto copper substrates with diameters of 20 mm, 25 mm, and 32 mm. The influence of substrate area on the I–V and I–L characteristics of the LEDs was systematically measured and analyzed at different operating temperatures. Additionally, variations in operating voltage and luminous intensity with temperature were investigated under specific driving currents. Infrared thermal imaging was employed to examine the thermal field distribution under varying substrate sizes and current levels. The results show that increasing the copper substrate diameter from 20 mm to 25 mm and further to 32 mm leads to a significant improvement in LED optoelectronic performance. To determine the diameter threshold beyond which performance gains diminish, a 3D COMSOL 6.1. model was developed. The model reveals that expanding the diameter from 32 mm to 35 mm results in only a marginal improvement, while further increasing it to 40 mm offers a negligible additional benefit, thereby identifying the optimal substrate area for performance saturation.