Abstract In this work, a new room-temperature ammonia gas sensor based on n-type copper oxide (CuO) semiconductor was fabricated by 3D printing with fused deposition modeling (FDM) technique and sintering method. The polylactic acid (PLA) was blended together with Cu particles and extruded into the filament form for FDM printing. The PLA/Cu composite was printed and calcined in a furnace to obtain semiconducting CuO. The structural characterization results of 3D printed sensor showed monoclinic CuO phase and scaffold structures, which provided active porous sites for enhanced gas adsorption and room-temperature gas-sensing performances. According to gas-sensing data, the 3D printed CuO gas sensor exhibited good repeatability, high stability (>3 months), low humidity dependency (25–65 %RH), high sensitivity and selectivity towards ammonia at room temperature. The sensor response increased linearly with increasing NH3 concentration from 25 to 200 ppm. The sensing mechanism of the 3D printed CuO sensor was proposed based on the resistance change via reaction on adsorbed surface oxygen species or direct electron transfer between ammonia molecules and CuO. This approach could open up new ways to fabricate semiconductor gas sensors with controllable sizes and shapes for future gas-sensing applications.

中文翻译：

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用于室温下氨检测的 3D 打印 CuO 半导体气体传感器

摘要 在这项工作中，采用熔融沉积建模 (FDM) 技术和烧结方法，通过 3D 打印制造了一种基于 n​​ 型氧化铜 (CuO) 半导体的新型室温氨气传感器。聚乳酸 (PLA) 与铜颗粒混合在一起并挤出成细丝形式用于 FDM 打印。PLA/Cu 复合材料被印刷并在炉中煅烧以获得半导体 CuO。3D打印传感器的结构表征结果显示出单斜CuO相和支架结构，为增强气体吸附和室温气敏性能提供了活性多孔位点。根据气体传感数据，3D 打印的 CuO 气体传感器表现出良好的重复性、高稳定性（>3 个月）、低湿度依赖性（25-65%RH）、在室温下对氨具有高灵敏度和选择性。传感器响应随着 NH3 浓度从 25 ppm 增加到 200 ppm 而线性增加。3D打印CuO传感器的传感机制是基于吸附表面氧物质的反应或氨分子与CuO之间的直接电子转移引起的电阻变化。这种方法可以开辟新的方法来制造具有可控尺寸和形状的半导体气体传感器，以用于未来的气体传感应用。