Low-Temperature Photochemically Activated Ethylene Glycol Sensor Based on Er Modified ZnO Nanorods

Ethylene glycol is a type of volatile organic compound (VOC), and its respiratory products pose significant risks to human and biological cells. Therefore, it is necessary to monitor the concentration of ethylene glycol in the environment. Metal oxide semiconductors (MOSs) exhibit good response to ethylene glycol gas. However, previous reports on ethylene glycol sensors have drawbacks such as high operating temperature and high-energy consumption, which cannot perfectly meet the needs of practical life. In this work, the photosensitive material ZnO was chosen as the sensing material for ethylene glycol, and the rare Earth element Er was composite into it, achieving high response to ethylene glycol under $70~^{\circ }$ C ultraviolet (UV) light. The results showed that the response value of 7% Er/ZnO to 100 ppm ethylene glycol was as high as 156.6, while retaining high selectivity for ethylene glycol gas. The combination of high response value of ethylene glycol and lower operating temperature near room temperature indicates that the sensor based on 7% Er/ZnO achieves a balance between sensitivity, response value, and operating temperature. UV spectroscopy and photoluminescence (PL) spectroscopy characterization confirmed that the energy levels of Er₂O₃ composite ZnO changed, effectively extending the lifetime of photograph-generated carriers. The mechanism of device performance optimization was analyzed through photocurrent testing. This work has basically achieved the photoactivation of ZnO gas sensors, providing ideas for the practical application of ethylene glycol gas monitoring.