C₆₀/Zeolite Semiconductor Electrode and the Gas Sensing

Abstract

Sodium Y type zeolite synthesized with homogeneous gels was deposited as thin films on tantalum toothcombs type electrode. C 60 molecules were deposited on the zeolite electrode surface by sublimation in a vacuum and were encapsulated in zeolite supercages by the thermal diffusion. The encapsulation was indicated by a decrease of the pore volume measured by argon gas adsorption. The potassium deposited K-C 60 /zeolite electrode as well as zeolite and C 60 /zeolite electrodes showed the behaviors characteristic to semiconductors in their measurements of currents in dark with temperature. The dependence of their dark currents on temperature was similar, which suggests that carrier formation through thermal band-gap excitation will be mainly caused by zeolite. The C 60 /zeolite and K-C 60 /zeolite electrodes showed rapid current responses repeatedly at 298 K under UV light irradiation. The introduction of oxygen gas to the C 60 /zeolite electrode under UV light irradiation resulted in both rapid and slow current decays with time. The current decreased and that remained in the rapid current decay were interpreted as contributions mainly from n-type (80%) and p-type character (20%), respectively. The slow current decay was interpreted by diffusion of oxygen into zeolite supercages. Ethylene sensing on the C 60 /zeolite electrode was possible in dark and showed a pressure dependency of Langmuir type isotherm. The result implies that such sensing is caused by compressing ethylene molecules in zeolite supercages.

A Low Cost Compact Measurement System Constructed Using a Smart Electrochemical Sensor for the Real-Time Discrimination of Fruit Ripening

“…An olefin detector based on the metal-organic framework was obtained to measure the ethylene gas by quenching fluorescence [ 20 ]. An electrochemical ethylene sensor constructed by a C60/Zeolite semiconductor electrode was investigated to monitor the ethylene gas in a wide concentration range [ 21 ]. A low-cost gas sensor produced by the graphite line-patterning technique was used to characterize banana ripening by examining the distinct pattern of signals [ 22 ].…”

Gas sensing using porous materials for automotive applications

“…A composite comprised of zeolite Y cages as hosts for C 60 has also been developed. 116 Two types of composites, C 60 /zeolite Y and K-C 60 /zeolite Y, were deposited onto tantalum comb-type electrodes providing semiconductor sensors. In the presence of ethylene, the composites exhibited measurable changes in conductivity.…”

Exploitation of Unique Properties of Zeolites in the Development of Gas Sensors

“…In another study, C 60 was deposited on zeolite Y films on a tantalum toothcomb type electrode, followed by thermal treatment to get the C 60 into the zeolite cages [ 47 ]. The zeolite-C60 composites as well as potassium-C60-zeolite electrodes exhibited semiconductor characteristics.…”