This paper discussed the effect of different thermal evaporation treatments for nanocomposited MEH-PPV:CNTs thin films towards the performance of organic solar cells. The configuration of the organic solar cells is ITO/MEH-PPV:CNTs/Au. The heating temperature was varied from, as deposited,50°C,75°C, and100°C. From the results, we observed that the efficiency increase slightly before decreasing back at100°C. The highest efficiency was solar cells heated at75°C with efficiency 0.001% which is supported by theI-Vcharacteristics and also by the absorption spectra.

This work focus on optical band gap of nanocomposited MEH-PPV:CNTs thin film. In this research we investigate the behavior of optical band gap when the composition of CNTs powder is increased which directly influence the thickness of the thin film. The experimental process entailed for the black powder of CNTs to be first annealed at 450 °C before mixing it with the polymer solution to ensure that the impurities in the CNTs are all removed. The 20 mg MEH-PPV polymer was dissolved in an aromatic solvent which is toluene with a concentration of 1:1. The composite materials were prepared by adding appropriate amounts of CNTs powder (1, 2, 3 and 4 wt%) into the polymer solution to make various ratios of CNTs powder/polymer composites. The optical properties of the thin film were analyzed by using Perkin Elmer Lambda 750 UV/Vis Spectrometer. Thickness of the thin film is measured using Surface profiler Veeco Dektak 150. In this paper, the optical band gap energy is derived by assuming a direct transition of electron between the edge of the valence band and the conduction band. Our results demonstrates that as the thickness decrease from 62, 60, 59, 58 and 57 nm, the optical band gap showed slight decrement from 2.07, 2.07, 2.05, 2.01 and 2.00 eV for respectively.

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Bulk heterojunction solar cell has received significant attention over the past decade due to low cost power generation and the potential to develop a clean renewable energy source [. We investigated the effect of different type of metal cathodes on the power conversion efficiency of bulk heterojunction solar cell based on a blend of conjugated polymer poly [2-methoxy 5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) with titanium dioxide (TiO2). In this case of study, Aluminum (Al) and gold (Au) has been chosen as the metal cathode due to the difference of work function and their wide application in hybrid solar cell. We show that the choice of metal cathode plays a role in determining overall device efficiency through their impact on short-circuit current, open circuit voltage and fill factor due to the influence of work function. It is found that the device employing Al metal cathode which has low work function is showing a comparable performance to the Au metal electrode with fill factor of over 20 % and a power conversion efficiency of 3.3x10-3 %. Overall it is demonstrated that the matching between the work function of the cathode and photoactive layer MEH-PPV: TiO2 is the most important factor towards best bulk heterojunction solar cell performance.

This paper explained the effect of solvent used to dissolve MEH-PPV powder in preparing the nanocomposited MEH-PPV:CNTs. The ratio of MEH-PPV powder to the solvent used is 1:1 (20 mg/ml). The solvents involved were toluene and tetrahydrofuran (THF). The preparation of the MEH-PPV solution took 48 hours of stirring to ensure that the MEH-PPV powder was well dissolved. After 48 hours of stirring, the black powder of annealed carbon nanotubes (CNTs) was added to the polymer solution. Both polymer solutions were added with 1,2,3 and 4 wt% of CNTs respectively. Nanocomposited MEH-PPV:CNTs thin film which used THF as the solvent is labelled as S1 where else S2 used toluene. The electrical properties of the two sets of samples are characterized by means of current-voltage in dark and under illumination. Where else, optical properties are done by measuring the absorbance and photoluminescence of the samples. From the results, it indicates that the conductivity in S2 is higher compared to conductivity under illumination in S1. Thickness of S2 is higher compared to S1. This indicates that THF as the solvent can ensure the dispersity of the CNTs in the nanocomposites. The optical properties indicate that S1 and S2 showed no peak shifting. Meanwhile in photoluminescence, S1 showed better quenching than S2.

This paper investigates performance of ZnO/SnO2 nanorods structure thin film deposited at two different ZnO seed layer (ZnO seed A and ZnO seed B) for humidity sensor application. ZnO seed A and ZnO seed B were deposited using two different method which were sputtering method and spin coating method respectively. ZnO/SnO2 nanorods structure thin film that has been prepared on ZnO seed A and ZnO seed B using thermal chemical vapor deposition (CVD). The structural properties have been characterized using field emission scanning electron microscopy (FESEM) (JEOL JSM 6701F). Base on the FESEM image the size of ZnO seed A and ZnO seed B were ranging around 75 to 85 nm and 17 to 21 nm respectively. The results analyzed were for ZnO/SnO2 composite nanorods structure size on ZnO seed A and ZnO seed B were averagely around 18 nm to 29 nm. The sensor properties were characterized by using current-voltage (I-V) measurement (Keithley 2400). ZnO/SnO2 nanorods structure thin film deposited on ZnO Seed A performed highest sensitivity with 265 ratio compare to ZnO/SnO2 nanorods structure thin film deposited on ZnO Seed B with 75 ratio of sensitivity.

In recent years, the research on organic solar cells systems based on nanocomposite containing conjugated polymers has lead to great attention with the aim or replacing conventional inorganic solar cells. This nanocomposite can be processed at lower cost, low weight and ease of synthesis with greater versatility than todays solar cell. In this study, we investigated the dependence of physical, optical and electrical properties on the thickness of MEH-PPV: TiO2 nanocomposite thin films for organic solar cell application. It was found the optical properties of photo-active layer MEH-PPV: TiO2 nanocomposite thin films improved with increasing its thickness however the electrical properties decreased. The absorption coefficients of photoactive layer are high in the visible region (400-600 nm) with optimum absorption region at 500 nm. The shift of absorption edge toward longer wavelength with increased of nanocomposite photoactive layer thickness due to narrowing band gap caused by the effects of electron-electron and electron-impurity scattering. In addition the study of illuminated current-voltage (I-V) characteristics revealed the increment of recombination process with increased of photoactive layer thicknesses. It was found such increased in resistivity from 136x103 to 1600x103 Ω.cm is closely related to the electric field and exciton dissociation which is decreased with increased photoactive thickness.