PeLEDs: Using Perovskites To Create LEDs Which Also Sense Light

With both of the dominant display technologies today – LCD and OLED – being far from perfect, there is still plenty of room in the market for the Next Big Thing. One of the technologies being worked on is called PeLED, for Perovskite LED. As a semiconductor material, it can both be induced to emit photons as well as respond rather strongly to incoming photons. That is a trick that today’s displays haven’t managed without integrating additional sensors. This technology could be used to create e.g. touch screens without additional hardware, as recently demonstrated by [Chunxiong Bao] and colleagues at Linköping University in Sweden and Nanjing University in China.

Their paper in Nature Electronics describes the construction of photo-responsive metal halide perovskite pixels, covering the typical red (CsPbI3−xBrx), green (FAPbBr3), and blue (CsPbBr3−xClx) wavelengths. The article also describes the display’s photo-sensing ability to determine where a finger is placed on the display. In addition, it can work as an ambient light sensor, a scanner, and a solar cell to charge a capacitor. In related research by [Yun Gao] et al. in Nature Electronics, PeLEDs are demonstrated with 1 microsecond response time.

As usual with perovskites, their lack of stability remains their primary obstacle. In the article by [Chunxiong Bao] et al. the manufactured device with red pixels was reduced to 80% of initial brightness after 18.5 hours. While protecting the perovskites from oxygen, moisture, etc. helps, this inherent instability may prevent PeLEDs from ever becoming commercialized in display technology. Sounds like a great challenge for the next Hackaday Prize!

12 thoughts on “PeLEDs: Using Perovskites To Create LEDs Which Also Sense Light

  1. Could that be used for adaptive brightness? Sense if it’s bright or dark and adjust the backlight level? Currently devices require camera or sensor to detect light level

  2. Perhaps a heterogeneous array is a better option.

    I can’t imagine the sensing actually REQUIRING a ‘retina’ sensor density to be useful.

    Maybe only use a single color PeLED of the longest lasting type, then deposit OLEDs for the other 2 colors?

    The paper talks about red degrading by 20% after 18ish hours. I can’t imagine blue is going to last 8000 hours. So maybe we need a hybrid panel with a different sub pixel layout that only illuminates the PeLEDs under specific/rare conditions while still using them to sense light.

    1. I thought the same, they are already sensors, you know, diodes like 1N4148 also, even 1N400x can catch some sort of solar radiation, or the good old 2N3055 with a hole in the hat. Those were the days!

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