Paderborn University , Warburger Straße 100, 33098 Paderborn, Germany.
ACS Sens. 2018 Jan 26;3(1):191-199. doi: 10.1021/acssensors.7b00845. Epub 2018 Jan 5.
Some metal oxide semiconductors, such as tungsten trioxide or tin dioxide, are well-known as resistive transducers for gas sensing and offer high sensitivities down to the part per billion level. Electrical signal read-out, however, limits the information obtained on the electronic properties of metal oxides to a certain frequency range and its application because of the required electrical contacts. Therefore, a novel approach for building an optical transducer for gas reactions utilizing metal oxide photonic crystals is presented here. By the rational design of the structure and composition it is possible to synthesize a functional material which allows one to obtain insight into its electronic properties in the optical frequency range with simple experimental measures. The concept is demonstrated by tungsten trioxide inverse opal structure as optical transducer material for hydrogen sensing. The sensing behavior is analyzed in a temperature range from room temperature to 500 °C and in a wide hydrogen concentration range (3000 ppm to 10%). The sensing mechanism is mainly the refractive index change resulting from hydrogen intercalation in tungsten trioxide, but the back reaction has also impact on the optical properties of this system. Detailed chemical reaction studies provide suggestions for specific sensing conditions.
一些金属氧化物半导体，如三氧化钨或二氧化锡，作为气体传感的电阻式传感器是众所周知的，其灵敏度可低至十亿分之一。然而，由于需要电接触，电信号读取将金属氧化物的电子特性的信息获取限制在一定的频率范围内及其应用。因此，本文提出了一种利用金属氧化物光子晶体构建用于气体反应的光学传感器的新方法。通过合理的结构和组成设计，可以合成一种功能材料，允许通过简单的实验测量在光学频率范围内获得对其电子特性的深入了解。该概念通过作为光学传感器材料的三氧化钨反蛋白石结构用于氢气传感进行了演示。在室温至 500°C 的温度范围内以及在宽浓度范围（3000ppm 至 10%）下分析了传感行为。传感机制主要是由于氢气在三氧化钨中的插层引起的折射率变化，但逆反应也对该系统的光学性质有影响。详细的化学反应研究为特定的传感条件提供了建议。
