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2022-08-08
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Through the integration of simple control circuits, LED can realize new display interaction

recently, an international research team composed of researchers from the United States and South Korea published a new type of nanoled, which has an unprecedented brightness level (more than 80000cd/m2), and can be used as a light emitter and a light detector at the same time

this research result was published in the journal Science. In the article "dual heterojunction nanorod light responsive led realizes display application", researchers expect that dual-mode LED can realize a new type of interactive display

this solution treated double heterojunction nanorod (dhnr) light response LED includes quantum dots that directly contact two different semiconductor materials in the nanorod. In this configuration, quantum dots can be biased according to the voltage, which can enhance radiation recombination (conducive to LEDs) or lead to the effective separation of photogenerated carriers that do not decompose at room temperature

the layered structure in these modified plastic products independently developed and produced by non isotropic nanorods can be adjusted separately, so as to fine tune the recombination and charge separation in a single component, so that a single nanorod can be electroluminescent and produce photocurrent. Once the nanorods are properly stacked between the two electrodes, the nanorods can be configured as a plastic extruder that switches between light-emitting mode and light detection mode by simply changing the voltage bias (forward or reverse), so as to improve the development space of export growth and make steady progress

the module is said to have a low on voltage (about 1.7V) and a maximum brightness of more than 80000cd/m2, and can show low bias and high efficiency in terms of display related brightness. The researchers also released that the module can support 8.0% external quantum efficiency with a brightness of 1000 cd/m2 at a bias voltage of 2.5V

but in another experiment, the researcher operated 10 × The dhnr-led array of 10 pixels acts as a field light detector (under reverse pressure) and is combined with a circuit board that can provide forward bias to any pixel to detect incident light

the energy band diagram of dhnr led and the charge flow direction of light emission (orange arrow) and detection (blue arrow), as well as the dhnr schematic diagram

by alternating forward and reverse bias voltage in sub millisecond time, they can continuously "read" the light detection pixels when illuminating the array

this experiment makes researchers believe that by integrating a simple control circuit to convert any detected signal into brightness adjustment, several new display features can be easily realized

for example, brightness can be automatically adjusted in response to changes in external light intensity. However, light detection can be performed at the pixel level to compensate for shadows on the screen, or finger proximity is detected and interpreted as a new touch free command

researcher Shandong new material industry has a strong industrial foundation and strong market space. Imagine the single pixel sensing ability of this dhnr-led, which can also support direct imaging or scanning of the screen. Another possible application of dhnr-led dual luminescence and light detection operation mode is to convert closely coupled LED displays (actually large nanoled arrays) into large-scale parallel data communication and processing components to perform direct data communication between displays

in addition, the light detection in the dhnr light response led is similar to the photoelectric (PV) effect. The display can collect or remove energy from the environmental light source without integrating separate solar cells, making the display more efficient. The last use case in the research theory also proved in experiments that LEDs can be coupled to supercapacitors

moonsub shim, a professor at the University of Illinois who led the study, said, "we have cooperated with Dow Chemical to apply for a patent for this technology. Therefore, it will bring certain commercial benefits in the future."

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