Noh Jinhong, Kwon Soon-Hwan, Park Sunghoon, Kim Kyoung-Kook, Yoon Yong-Jin
Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
Department of Advanced Convergence Technology, Research Institute of Advanced Convergence Technology, Korea Polytechnic University, Siheung-si 15073, Korea.
Sensors (Basel). 2021 Mar 5;21(5):1826. doi: 10.3390/s21051826.
Because the oxides of nitrogen (NO) cause detrimental effects on not only the environment but humans, developing a high-performance NO gas sensor is a crucial issue for real-time monitoring. To this end, metal oxide semiconductors have been employed for sensor materials. Because in general, semiconductor-type gas sensors require a high working temperature, photoactivation has emerged as an alternative method for realizing the sensor working at room temperature. In this regard, titanium dioxide (TiO) is a promising material for its photocatalytic ability with ultraviolet (UV) photonic energy. However, TiO-based sensors inevitably encounter a problem of recombination of photogenerated electron-hole pairs, which occurs in a short time. To address this challenge, in this study, TiO nanorods (NRs) and Pt nanoparticles (NPs) under a UV-LED were used as an NO gas sensor to utilize the Schottky barrier formed at the TiO-Pt junction, thereby capturing the photoactivated electrons by Pt NPs. The separation between the electron-hole pairs might be further enhanced by plasmonic effects. In addition, it is reported that annealing TiO NRs can achieve noteworthy improvements in sensing performance. Elucidation of the performance enhancement is suggested with the investigation of the X-ray diffraction patterns, which implies that the crystallinity was improved by the annealing process.
由于氮氧化物（NO）不仅会对环境造成有害影响，还会危害人类健康，因此开发一种高性能的NO气体传感器对于实时监测至关重要。为此，金属氧化物半导体已被用作传感器材料。一般来说，半导体型气体传感器需要较高的工作温度，光活化已成为实现室温下工作的传感器的一种替代方法。在这方面，二氧化钛（TiO₂）因其具有利用紫外（UV）光子能量的光催化能力而成为一种有前途的材料。然而，基于TiO₂的传感器不可避免地会遇到光生电子-空穴对在短时间内复合的问题。为应对这一挑战，在本研究中，将紫外发光二极管（UV-LED）照射下的TiO₂纳米棒（NRs）和铂纳米颗粒（NPs）用作NO气体传感器，以利用TiO₂-Pt结处形成的肖特基势垒，从而通过Pt NPs捕获光活化电子。电子-空穴对之间的分离可能会通过等离子体效应进一步增强。此外，据报道，对TiO₂ NRs进行退火可以显著提高传感性能。通过对X射线衍射图谱的研究对性能增强进行了阐释，这表明退火过程提高了结晶度。
