M. Yahya

Optimizing of the inkjet printing technique parameters for fabrication of bulk heterojunction organic solar cells

The inkjet printing technique is a promising alternative deposition technique due to its effectiveness in material use and large area coverage. However, the printed film morphology critically depends on the droplets characteristics. This paper reports the optimizing of several key printing parameters, such as pulse voltages, drop spacing and waveform setting for obtaining the high quality droplets and printed film for organic solar cell application. The organic printed film is an active layer of bulk heterojunction solar cells that is composed of blended poly (3-octylthiophene)(P3OT) and (6,6)-phenyl C71 butyric acid methyl ester (PCBM). The film was printed on ITO coated glass substrate. The absorption and morphology study of the printed film and the performance of photovoltaic devices characterized by current-voltage measurement in the dark and under illumination are reported. The dependence of setting of printing parameters on the droplets and film quality will be discussed.

Characterization of SnO2 Nanoparticles Prepared by Two Different Wet Chemistry Methods

Effects of synthesis techniques, namely sol gel method and direct growth method on the nanostructural and optical properties of SnO2 have been investigated. The XRD results confirmed that both samples are single phase SnO2. The crystallite size of SnO2 prepared by sol-gel and direct growth method were approximately 10 nm and 15 nm respectively. The FE-SEM micrographs displayed that SnO2 nanoparticles prepared by sol gel method exhibited a round shape with approximate particle size of 10 nm while the direct growth method produced SnO2 nanorod with length and width of 570 nm and 55 nm respectively. The direct Eg for both SnO2 nanospheres and nanorods are 3.98 eV and 3.94 eV respectively, Due to quantum confinement effect, both nanomaterials exhibited strong blue shift compared to bulk material with Eg of 3.6 eV.

The growth of Sn doped ZnO nanobelts and their properties

Sn doped ZnO nanobelts have been synthesized by using thermal evaporation method. Sn powder was mixed with the ZnO and graphite grain powder as the growth reactant for obtaining doped ZnO nanobelts. This nanobelts was prepared under nitrogen ambient and at temperature 1000°C. The nanobelts formed were observed under X-ray diffraction (XRD), scanning electron microscope (SEM) and analysis of its electrical and optical properties also was determined. The growth mechanisms of the Sn doped ZnO nanobelt and its potential applications are further discussed.

Enhanced-photoluminescence properties of CdTe quantum dots prepared from the ternary surfactant mixture system

This paper reports the synthesis and characterization of CdTe system in the ternary surfactant mixture. The quantum dots was prepared by quick injection of tri-n-octylphosphine telluride (TOPTe) into reactor that contains a hot mixed cadmium acetate hydrate, 1-octadecene, n-octadecyl phosphoric acid (ODPA), octadecylamine (ODA) and oleic acid (OA). We found that the surfactant of ODPA, OA and ODA were very important for the enhancement at the Photoluminescence (PL) properties CdTe quantum dots.

Facile Approach for Preparing CdSe/CdTe Heterostucture Quantum Dots

This paper reports a simple strategy to synthesize CdSe/CdTe heterostucture Quantum Dots (QDs) via successive injection of selenium and tellurium precursors into cadmium precursor at 350° C. In typical process, it was found that the heterostucture QDs exhibited a totally new absorption and photoluminescence (PL) properties that are different from individual CdSe and CdTe properties. For example, its PL emissions Quantum Yield (QY) were triple of CdSe and five times of CdTe high quantum QY, the heterostucture QDs should be potential used in LED and solar cell applications.

The Dependence of Donor:Acceptor Ratio on the Photovoltaic Performances of Blended poly (3‐octylthiophene‐2,5‐diyl) and (6,6)‐phenyl C71 butyric acid methyl ester Bulk Heterojunction Organic Solar Cells

Bulk heterojunction organic solar cells using blended poly (3‐octylthiophene‐2,5‐diyl)(P3OT) and (6,6)‐phenyl C71 butyric acid methyl ester (PC71BM) have been fabricated. P3OT and PC71BM were used as the electron donor (D) and acceptor (A), respectively. Both materials were mixed and dissolved in dichlorobenzene with three different D:A ratios i.e. 1:3, 1:1 and 3:1 (weight) while maintained at the concentration of 2 wt% (26 mg/ml). The blended thin films were sandwiched between the indium tin oxide (ITO) coated glass and the aluminum film. This paper reports the influence of donor:acceptor ratio on the performance of solar cell devices measured by current‐voltage measurement both in the dark and under 1.5 AM solar illumination. It was found that all devices showed the photovoltaic effect with poor diode behavior and the donor:acceptor ratio significantly influenced on the performance of bulk heterojunction organic solar cells.