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» متحسس الرطوبة للكوبلت فثالوسيانين المحضّر بالصب النقطي // Cobalt-Phthalocyanine Humidity Sensor Prepared by Drop Casting
متحسس الرطوبة للكوبلت فثالوسيانين المحضّر بالصب النقطي // Cobalt-Phthalocyanine Humidity Sensor Prepared by Drop Casting
رسالة متاحة للتحميل - علوم الفيزياء
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متحسس الرطوبة للكوبلت فثالوسيانين المحضّر بالصب النقطي
Cobalt-Phthalocyanine Humidity Sensor Prepared by Drop Casting
لــ : معتز سعدي بدري
ماجستير علوم الفيزياء
جامعة بغداد - كلية العلوم 2015
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Abstract
Cobalt Phthalocyanine (CoPc) films have been prepared by drop casting and thermal evaporation technique on glass substrate at RT under vacuum of 5x10–6 mbar with a rate of deposition equals to 22 nm/min
The optical measurements represented by UV-Visible spectrum showed two bands of absorption (B and Q). The CoPc thin films have a direct energy gap (Eg) equals to 3.41eV and two trap energies equal to (1.84 and 1.64)eV. Also the optical constants such as absorption coefficient, refractive index, extinction coefficient and dielectric constant have been calculated.
The structural and morphological properties of CoPc films have been studied by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) techniques. (XRD) studies show that the structure of the films prepared by drop casting is polycrystalline with a monoclinic structure while thin films prepared by vacuum thermal evaporation have a single crystalline structure for two temperatures (RT and 428K) with (100) orientation . The grain size of average equals to about 76nm of CoPc films were determined by (XRD) and (AFM), while the roughness of average equals to about 4nm was determined by (AFM) and (SEM) methods.
The electrical properties (capacitance and resistance), which have been employed as a humidity sensor and investigated at different relative humidity levels and frequencies, indicate that the capacitance increases nonlinearly with relative humidity while the resistance decreases, and both of capacitance and resistance decrease nonlinearly with increasing frequency at a given relative humidity.
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