New black technology nanoLED makes display more efficient

Technology Dynamics An international team of researchers from the United States and South Korea published a new type of nanoLED, which is said to have an unprecedented brightness level and can be used simultaneously as an optical transmitter and a photodetector, as well as to include a new type of interactive display. Wait.

New black technology nanoLED makes display more efficient

This fully solution-treated double heterojunction nanorod (DHNR) photoresponsive LED includes quantum dots that directly contact two different semiconductor materials in a nanorod. In this configuration, the quantum dots are biased according to the voltage, which enhances the radiative recombination (in favor of the LED) or causes efficient separation of the photocarriers. The layered structure in these non-isotropic nanorods can be individually adjusted to fine tune the recombination and charge separation in a single assembly so that a single nanorod can electroluminesce and generate a photocurrent. Once the nanorods are properly stacked between the two electrodes, the nanorods can be configured as pixels to switch between the light emitting mode and the light detecting mode by simply changing the voltage bias (forward or reverse). . This component is said to have a low turn-on voltage (approximately 1.7V) and a maximum brightness of over 80,000 cd/m 2 , and can exhibit low bias and high efficiency in display-related brightness.

The researchers also announced that the device can support an external quantum efficiency of 8.0% at a brightness of 1000 cd/m2 at a bias of 2.5V. In another experiment, the researchers manipulated a 10×10 pixel DHNR-LED array as an on-site photodetector (in reverse voltage), and combined with one to provide forward bias to any pixel to detect incident light. Circuit board. By alternately biasing the forward and reverse biases in sub-millisecond stages, they are able to "read" light-sensing pixels continuously while illuminating the array. The experiment allows researchers to think that several new display features can be easily implemented by integrating a simple control circuit to convert any detected signal to brightness adjustment. For example, the brightness can be adjusted automatically in response to changes in the external light intensity. However, since the light detection can be performed at the pixel level, the shadow on the screen is compensated or the finger is detected and interpreted as a new touch-free command. Instead of the single pixel sensing capability of this DHNR-LED, it can support direct imaging or scanning of the screen. In addition, the light detection in the DHNR photoresponsive LED is similar to the photovoltaic (PV) effect, and the display can collect or remove energy from ambient light sources without the need to integrate separate solar cells to make the display more efficient.