Luo Junxian, Liu Shen, Chen Peijing, Chen Yanping, Zhong Junlan, Wang Yiping
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education/Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Shenzhen Key Laboratory of Photonic Devices and Sensing Systems for Internet of Things, Guangdong and Hong Kong Joint Research Centre for Optical Fibre Sensors, Shenzhen University, Shenzhen 518060, China.
ACS Appl Mater Interfaces. 2022 Jun 29;14(25):29357-29365. doi: 10.1021/acsami.2c04105. Epub 2022 Jun 15.
Nanofilm resonators combine ultracompact and highly mechanically sensitive properties, making them intriguing devices for sensing applications. For trace hydrogen detection, we demonstrate an optomechanical nanofilm resonator by employing a Pd- and Au-decorated graphene onto a fiber end facet. The Pd layer is a sensitive layer for selective absorption of hydrogen. Hydrogen sensing is achieved by all-optical measuring of the resonant frequencies shift of the optomechanical nanofilm resonator induced by hydrogen-related mechanical stress change. Using the approach, we realize highly sensitive hydrogen sensing at room temperature with a low detection limit, challenging the state-of-the-art. When the measured hydrogen concentration increases from 0 to 1000 ppm (v/v), the mechanical resonance frequencies of the sensor at 511.7 kHz, 1253.4 kHz, and 2231.7 kHz blue-shift by 100.4 kHz, 257.5 kHz, and 400.6 kHz, respectively. The response and recovery time are 120.3 and 91.3 s at a 1000 ppm hydrogen concentration. Such a sensor exhibits a low detection limit of 741 ppb and good repeatability in the measurement process, which makes the practical application of the sensor possible.
纳米薄膜谐振器兼具超紧凑和高机械灵敏度的特性，使其成为传感应用中极具吸引力的器件。对于痕量氢气检测，我们通过在光纤端面采用钯和金修饰的石墨烯来展示一种光机械纳米薄膜谐振器。钯层是用于选择性吸收氢气的敏感层。氢气传感通过对光机械纳米薄膜谐振器因氢气相关机械应力变化而引起的谐振频率偏移进行全光学测量来实现。采用这种方法，我们在室温下实现了具有低检测限的高灵敏度氢气传感，对现有技术构成了挑战。当测量的氢气浓度从0增加到1000 ppm（v/v）时，传感器在511.7 kHz、1253.4 kHz和2231.7 kHz处的机械谐振频率分别蓝移100.4 kHz、257.5 kHz和400.6 kHz。在1000 ppm氢气浓度下，响应时间和恢复时间分别为120.3秒和91.3秒。这种传感器具有741 ppb的低检测限和测量过程中的良好重复性，这使得该传感器的实际应用成为可能。
