Highly Integrated In Situ Photoenergy Gas Sensor with Deep Ultraviolet LED

According to the demands of the Internet of Things (IoTs), a gas sensor is demanded to be small, portable, and easy to integrate with the environment or structure in its application. Herein, an ingenious form of in situ photoenergy gas sensor integrated with a deep ultraviolet light-emitting diode (LED) has been designed to achieve ppb level NO₂ gas detection at room temperature. In this gas sensor, the deep ultraviolet LED based on AlGaN materials, which has a wider band gap and higher photoexcitation energy, acts as the substrate with emission at 280 nm. The ZnO nanorods of the gas-sensing material were directly grown on 2 inch AlGaN-based LEDs containing thousands of independent light-emitting chips, leading to photosensitive materials with uniform and controllable, as well as a sensor with low power consumption and mass manufacture with low cost. The result shows that responses of over 500% to 500 ppb of NO₂ were observed by in situ irradiation of just 3 mW optical power. Meanwhile, sensitivity without real-time photoenergy is defined as the ratio of the resistance change rate in pollutant to that in air has been presented. Interestingly, the prototype gets in situ photoenergy charge for 5 min and then has responses of over 200% to 500 ppb of NO₂ for 5 days in the dark. It may open a new avenue for the integrated microchip design of a gas sensor and give a novel sight into the sensitivity study without real-time assisted energy.