Preparation of Ag-doped ZnO/CuO Heterojunction Gas Sensor with Room Temperature
| Autor: | CHAO, SYUN-RU, 趙珣如 |
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| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 In this study, inkjet printing technology was used to prepare a looped electrode composed of silver nanoparticles on flexible polyimide (PI) films. Pure ZnO and CuO were synthesized by hydrothermal method. ZnO, CuO and Ag doped ZnO/CuO were used as sensing layer and coated onto sliver electrode. To improve the traditional semiconductor gas sensor needs to be applied the high temperature environment, the gas sensing was tested under room temperature with UV LED. Silver particles was synthesized by a simple polyol reduction method. The silver nanoparticle was formulated into 5 wt% silver ink, and the ink was filled in a commercially available EPSON T50 printer ink cartridge. The silver loop type electrode is printed on the polyimide film and then coated with a layer of gas sensitive material, wherein the sensing layer is ZnO (N-type), CuO (P-type), the formation of heterogeneous interface (P-N Junction) of ZnO mixed with CuO (ZnO/CuO), and silver doped ZnO/CuO to complete the preparation of sensors. The sensors are placed in a homemade gas sensing chamber, and the sensing test is carried out under reducing gas atmosphere (0-400 ppm) at room temperature with a low wattage UV-LED (10 W) lamp irradiated. The sensors was connected to a source meter (Keithley 2400), and the current value was read at different reducing gas concentrations. After the computer software was recorded, the sensing performance of the gas sensor at room temperature was investigated. The gas sensing results revealed that the Ag doped Zno/CuO based gas sensor has superior gas sensing properties like, high response(95.9), good stability, and fast response (3 s) and recovery (5 s) time towards 50 ppm acetone gas at room temperature compared to pure ZnO(37.7/4 s/6 s), CuO(28.3/34 s/12 s)and ZnO/CuO(63.2/5 s/7 s) based sensors. The sensed instantaneous current value significantly changed with increasing acetone gas concentration, and was an effective acetone gas sensor. The sensors with UV-LED can effectively improve the limitations of conventional metal oxide semiconductor gas sensors operating at high operating temperature, and Ag doped ZnO/CuO gas sensor have good sensing ability for the acetone gas with low ppm concentration at room temperature. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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