An optical humidity sensor based on CdTe nanocrystals modified porous silicon

作者：Hu Jing; Wu Peng; Deng Dongyan; Jiang Xiaoming; Hou Xiandeng^*; Lv Yi

来源：Microchemical Journal, 2013, 108: 100-105.

DOI：10.1016/j.microc.2012.10.005

• CdTe nanocrystals
• Porous silicon
• Photoluminescence
• Humidity sensor

In this work, mimicking the preparation of solid catalyst in heterogeneous catalysis, a composite for sensing was constructed by the loading of mercaptopropionic acid (MPA) capped CdTe nanocrystals (NCs) on the porous silicon surface (PSi/CdTe NCs composite). Since water vapor could effectively enhance the photoluminescence of CdTe NCs on PSi, the as-prepared composite was engineered into an optical humidity sensor. Time-resolved fluorescence measurements showed that the loading of CdTe NCs onto PSi and post-photoradiation led to the generation of surface traps on the surface of CdTe NCs. Upon adsorption of water molecules, the amounts of surface traps were effectively decreased, thus providing PL improvement By employing the proper modification strategy, this humidity sensor achieved the convenience and repeatability in construction of the sensing layer, good sensitivity and stability. This humidity sensor also shows good selectivity against common volatile organic compounds. For absolute humidity, the linear range was 2-40 mu g/mL in N-2 or 1.3-26.7 mu g/mL in dry air, both with a limit of detection of 0.3 mu g/mL For relative humidity (RH), the linear range could be from 12% to 93% at 20 degrees C. This sensor was also successfully applied in the RH determination of real air samples, with results well agreed with a commercial hygrometer.

• 出版日期2013-5
• 单位四川大学