Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Small. 2023 Jul;19(27):e2207165. doi: 10.1002/smll.202207165. Epub 2023 Mar 28.
Photoactivated gas sensors that are fully integrated with micro light-emitting diodes (µLED) have shown great potential to substitute conventional micro/nano-electromechanical (M/NEMS) gas sensors owing to their low power consumption, high mechanical stability, and mass-producibility. Previous photoactivated gas sensors mostly have utilized ultra-violet (UV) light (250-400 nm) for activating high-bandgap metal oxides, although energy conversion efficiencies of gallium nitride (GaN) LEDs are maximized in the blue range (430-470 nm). This study presents a more advanced monolithic photoactivated gas sensor based on a nanowatt-level, ultra-low-power blue (λ = 435 nm) µLED platform (µLP). To promote the blue light absorbance of the sensing material, plasmonic silver (Ag) nanoparticles (NPs) are uniformly coated on porous indium oxide (In O ) thin films. By the plasmonic effect, Ag NPs absorb the blue light and spontaneously transfer excited hot electrons to the surface of In O . Consequently, high external quantum efficiency (EQE, ≈17.3%) and sensor response (ΔR/R (%) = 1319%) to 1 ppm NO gas can be achieved with a small power consumption of 63 nW. Therefore, it is highly expected to realize various practical applications of mobile gas sensors such as personal environmental monitoring devices, smart factories, farms, and home appliances.
与微发光二极管（µLED）完全集成的光激活气体传感器由于其低功耗、高机械稳定性和大规模生产能力，已经显示出替代传统微/纳机电（M/NEMS）气体传感器的巨大潜力。以前的光激活气体传感器大多利用超紫外线（UV）光（250-400nm）来激活高带隙金属氧化物，尽管氮化镓（GaN）LED 的能量转换效率在蓝色范围内（430-470nm）达到最大值。本研究提出了一种更先进的基于纳瓦特级、超低功耗蓝色（λ=435nm）µLED 平台（µLP）的单片光激活气体传感器。为了提高传感材料对蓝光的吸收，在多孔氧化铟（In O ）薄膜上均匀涂覆了等离子体银（Ag）纳米颗粒（NPs）。通过等离子体效应，Ag NPs 吸收蓝光并将激发的热电子自发地转移到 In O 的表面。因此，在 63nW 的小功耗下，可以实现对 1ppm NO 气体的高外量子效率（EQE，约 17.3%）和传感器响应（ΔR/R（%）=1319%）。因此，非常有望实现移动气体传感器的各种实际应用，如个人环境监测设备、智能工厂、农场和家用电器。
