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1 – 2 of 2Yankun Tang, Ming Zhang, Kedong Chen, Sher Ali Nawaz, Hairong Wang, Jiuhong Wang and Xianqing Tian
Detecting O2 gas in a confined space at room temperature is particularly important to monitor the work process of precision equipment. This study aims to propose a miniaturized…
Abstract
Purpose
Detecting O2 gas in a confined space at room temperature is particularly important to monitor the work process of precision equipment. This study aims to propose a miniaturized, low-cost, mass-scale produced O2 sensor operating around 30°C.
Design/methodology/approach
The O2 sensor based on lanthanum fluoride (LaF3) solid electrolyte thin film was developed using MEMS technology. The principle of the sensor was a galvanic cell H2O, O2, Pt | LaF3 | Sn, SnF2 |, in which the Sn film was prepared by magnetron sputtering, and the LaF3 film was prepared by thermal resistance evaporation.
Findings
Through pretreatments, the sensor’s response signal to 40% oxygen concentration was enhanced from 1.9 mV to 46.0 mV at 30°C and 97.0% RH. Tests at temperatures from 30°C to 50°C and humidity from 32.4% RH to 97.0% RH indicated that the output electromotive force (EMF) has a linear relationship with the logarithm of the oxygen concentration. The sensitivity of the sensor increases with an increase in both humidity and temperature in the couple mode, and the EMF of the sensor follows well with the Nernst equation at different temperatures and humidity.
Practical implications
This research could be applied to monitor the oxygen concentration below 25% in confined spaces at room temperature safely without a power supply.
Originality/value
The relationship between temperature and humidity coupling and the response of the sensor was obtained. The nano-film material was integrated with the MEMS process. It is expected to be practically applied in the future.
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Aleksandra Drygała, Marek Szindler, Magdalena Szindler and Ewa Jonda
The purpose of this paper is to improve the efficiency of dye-sensitized solar cells (DSSCs) which present promising low-cost alternative to the conventional silicon solar cells…
Abstract
Purpose
The purpose of this paper is to improve the efficiency of dye-sensitized solar cells (DSSCs) which present promising low-cost alternative to the conventional silicon solar cells mainly due to comparatively low manufacturing cost, ease of fabrication and relatively good efficiency. One of the undesirable factor in DSSCs is the electron recombination process that takes place at the transparent conductive oxide/electrolyte interface, on the side of photoelectrode. To reduce this effect in the structure of the solar cell, a TiO2 blocking layer (BL) by atomic layer deposition (ALD) was deposited.
Design/methodology/approach
Scanning electron microscope, Raman and UV-Vis spectroscopy were used to evaluate the influence of BL on the photovoltaic properties. Electrical parameters of manufactured DSSCs with and without BL were characterized by measurements of current-voltage characteristics under standard AM 1.5 radiation.
Findings
The TiO2 BL prevents the physical contact of fluorine-doped tin oxide (FTO) and the electrolyte and leads to increase in the cell’s overall efficiency, from 5.15 to 6.18%. Higher density of the BL, together with larger contact area and improved adherence between the TiO2 layer and FTO surface provide more electron pathways from TiO2 to FTO which facilitates electron transfer.
Originality/value
This paper demonstrates that the introduction of a BL into the photovoltaic device structure is an important step in technology of DSSCs to improve its efficiency. Moreover, the ALD is a powerful technique which allows for the highly reproducible growth of pinhole-free thin films with excellent thickness accuracy and conformality at low temperature.
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