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خصائص الاغشية الرقيقة للمركب MEH-PPV المشوب بالمعدن كمتحسس غازي == Characterization of metal doped MEH-PPV Thin films for gas sensor
Author name:
نور مثنى جبار
Supervisor name:
مصطفى محمد علي حسين
General topic:
Physics
Specific topic:
Laser Physics and Electro-optics
Degree:
Master
University:
University of Baghdad
Language:
English
University location:
Baghdad
Key words:
- MEH-PPV
- gas sensor
First pages:
T107045 - p.pdf
Abstract:
Abstract In this study, optimized thin films were prepared to measure the gas sensor. Thin films of the nanocomposite were prepared from mixing poly(2- methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV):Ferric Chloride (FeCl3) with different weight ratios and were prepared by spin coating and drop casting methods. Some physical properties of the thin films of pure MEH-PPV nanocomposite and doping FeCl3 were measured at different weight ratios (0.03wt%, 0.06wt%, 0.09wt% and .0.12wt%). When (FTIR) was measured, it was found that a physical reaction occurred and no chemical one between MEH-PPV and FeCl3. As for the measurement of (FESEM), the pure sample MEH-PPV was homogeneous, but when FeCl3 was added in different weight percentages (0.03wt%, 0.06wt%, 0.09 wt% and 0.12wt%) prominent circles were formed indicating the formation of adsorption and it increases as the concentration percentage increases, and the highest adsorption appears in MEH-PPV:FeCl3 (0.06%). Also, by measuring (EDX), The results demonstrate that there are no unwanted elements in the samples. Some elements were found this may due to the contaminator champers which used to test. It also indicates the presence of small peaks of iron (Fe) and chlorine (Cl). Carbon peaks indicate (C) and oxygen (O) to the presence of the chemical elements of MEH-PPV. And when the (UV-Vis) was measured, Determining the band gap for thin films, where it was found that there are two energy gaps, the first region is Q band, and this was an nonsystematic behavior, and the second region is B band, and here the energy gap increases when the ratio of doping increases. It is noted that the MEHPPV polymer has an absorption peak at the wavelength of 490 nm, and when FeCl3 is added, a blue shift is noticed towards short wavelengths at 453 nm. When the Hall effect was measured, it was found that the conductivity and carrier mobility increase when the doping concentration ratio increases. As well as for the measurement of sensors based on MEH-PPV:FeCl3, a Abstract II noticeable response appeared when the sensor was exposed to H2S gas at a concentration of 25 ppm, where the maximum sensitivity at MEHPPV/FeCl3 (0.06%) was 57.36% at an operating temperature of 175°C with a response time (9sec) and recovery time (55.8sec)
Summary:
4133a9d302.pdf
References:
9172438d87.pdf
