Resonant-enhanced full-color emission of quantum-dot-based micro LED display technology

Abstract

Colloidal quantum dots which can emit red, green, and blue colors are incorporated with a micro-LED array to demonstrate a feasible choice for future display technology. The pitch of the micro-LED array is 40 μm, which is sufficient for high-resolution screen applications. The method that was used to spray the quantum dots in such tight space is called Aerosol Jet technology which uses atomizer and gas flow control to obtain uniform and controlled narrow spots. The ultra-violet LEDs are used in the array to excite the red, green and blue quantum dots on the top surface. To increase the utilization of the UV photons, a layer of distributed Bragg reflector was laid down on the device to reflect most of the leaked UV photons back to the quantum dot layers. With this mechanism, the enhanced luminous flux is 194% (blue), 173% (green) and 183% (red) more than that of the samples without the reflector. The luminous efficacy of radiation (LER) was measured under various currents and a value of 165 lm/Watt was recorded.

25.1: Invited Paper: Quantum dots based full‐color display on micro‐light‐emitting‐diode technology

“…The top-view image of the micro display in our previous research is shown in Fig. 6(b) [3]. The red line depicts the overlap of the blue and green lines, which caused the cross-talk effect to induce the pixels with a color shift.…”

“…QDs have attracted much attention, as the large-area color gamut than can be achieved with their narrow linewidths. In our previous research [3], a full-color emitting panel is achieved by combining RGB QDs with micro-UV LEDs of 35 μm × 35 μm pixel size and in 128 × 128 arrays. Generally, the mainly light utilization efficiency loss of the LCD display is from backlight system.…”

The colloidal quantum dots and their applications on hybrid optoelectronic devices

“…The small volume and high efficiency properties of CQDs are suitable for small devices when compared to regular yellow phosphors, but how to uniformly distribute the CQDs to a large number of units is the main issue for this technology to be successful. With the help of pulsed spray and aerosol jet ® methods, the CQD patterns with size of several tens of microns can sprayed onto the devices in array format [11]. This method can be effective if several printing heads can be deployed at the same time.…”

High performance color‐converted micro‐LED displays

“…However, the fabrication process is complicated since different semiconductor substrates are required for growing blue/green micro‐LEDs and red micro‐LED. Another simpler method utilizes single‐color micro‐LEDs to excite the color converters, such as phosphors or quantum dots (QDs) . For example, UV LED array with pixelated RGB QDs can achieve high efficiency and wide color gamut because no color filter is needed.…”