F. S. S. Zahid

Investigation on I-V for Different Heating Temperatures of Nanocomposited MEH-PPV:CNTs Organic Solar Cells

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, C, C, and C. From the results, we observed that the efficiency increase slightly before decreasing back at C. The highest efficiency was solar cells heated at C with efficiency 0.001% which is supported by the I-V characteristics and also by the absorption spectra.

Photoconductivity of nanocomposited MEH-PPV: CNTs thin film for organic solar cells application

Our work focused on nanocomposite MEH-PPV: CNTs prepared by spin coating technique. The MEH-PPV which is in powder form (commercially available) was weighted and then dissolved in Toluene and stirred for 48 hours. Then, a small amount of CNTs were added to the MEH-PPV solution. It is sonicated for 1 hour to ensure that CNTs is well dispersed in the MEH-PPV solution. The addition of CNTs in the MEH-PPV solution yields a nanocomposite MEH-PPV:CNTs solution. The electrical properties of the thin films were studied to identify whether the nanocomposite thin films have ohmic capability or vice versa. Optical properties of the thin films were characterized using UV-VIS-NIR spectrophotometer. From the current-voltage characteristics it can be seen that there is no photo response when light is illuminated to the sample of MEH-PPV blend CNTs. The highest conductivity is at 2 wt% concentration of CNT with 100k Sm−1. It also gives the highest value of absorption spectra which is 0.25 for nanocomposite MEH-PPV: CNTs thin film.

Photoconductivity of MEH-PPV:TiO 2 nanocomposite thin film

In this research the photoconductivity of a hybrid nanocomposite thin film based on poly(2-methoxy-5-ethylhexyloxy-1,4-phenylene)vinylene (MEH-PPV) and anatase nanopowder TiO2 are studied. The MEH-PPV:TiO2 nanocomposite thin film deposited on a glass substrate have been prepared at different composition of TiO2 nanopowder (from 5wt% to 20wt%) by spin-coating method. The current-voltage (I–V) characteristics are measured by two point probe solar simulator measured in dark and under illumination. It was found that the photoconductivity showed increment in value as the composition of TiO2 increase in the polymer based solution. The optical characterization is carried out via UV-Visible absorption spectroscopy to investigate the absorbance and optical band gap.

Iodine doped multiwall carbon nanotubes in MEH-PPV:I-MWCNTs nanocomposite for organic solar cell applications

This paper discussed the effect of different composition ratio of Iodine doped multiwalled carbon nanotubes (I-MWCNTs) in MEH-PPV for organic solar cell applications. The I-MWCNTs compositions were varied from 0, 30, 50, 60 and 80 wt% and the effect to the electrical, optical and physical properties were investigated. The MWCNTs was doped with acceptor atoms which is Iodine, before it is being mix to the MEH-PPV solution. This nanocomposited MEH-PPV:I-MWNTs solution was deposited on glass and ITO substrates by spin coating technique. The photo-current showed linearly increased as the composition ratio increase, meanwhile the photoconductivity showed the highest value at 60 wt% with 0.16 Ω/m. This value is supported by the value of absorption coefficient which is around 9.7 × 105 m-1. Therefore, 60 wt% was used to fabricate organic solar cells, which gave efficiency around 0.0008%, Voc = 0.094 V, Jsc = 0.031 mA/cm2 and fill factor = 0.269.

Conductivity enhancement of nanocomposited MEH-PPV:I-MWNT thin film

In this paper, we report the electrical conductivity of nanocomposited MEH-PPV:I-MWNT thin film by varying the composition of Iodine doped multi-walled nanotubes (I-MWNT) in MEH-PPV matrix from 0, 2 and 4 wt%. Electrical conductivity showed increasing in value as the composition of I-MWNT increased from 0, 2 to 4 wt%. The value of conductivity is very outstanding when the polymer was blended with I-MWNT where the value rise from pure MEH-PPV, 81.6 × 10-4 S/m to 67.68 × 104 and 80.28 × 104 S/m for 2 and 4 wt% respectively. The surface morphology was investigated using atomic for microscopy (AFM). Roughness of the thin film showed decrement in value from 5.385 nm, 0.751 nm and 0.643 nm for 0, 2, and 4 wt% respectively. Meanwhile, the absorbance value increase slightly from about 0.16 (0 wt%) to about 0.165 and 0.17 (2 and 4 wt% respectively). The low absorbance shows that low photon is absorbed and therefore, there is no current changes when the sample is illuminated compared to in dark.

Effect of thickness on the electrical and optical properties of MEH-PPV:TiO 2 nanocomposite for organic solar cell application

The performance and properties of organic/inorganic nanocomposited poly[2-methoxy 5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV):TiO2 thin film at different thickness was investigated. MEH-PPV:TiO2 nanocomposite thin film has been prepared on indium tin oxide (ITO) substrate using spin-coating method with different deposition time from 1 to 10 times at room temperature. The effect of different thickness on the electrical and optical properties of MEH-PPV:TiO2 was characterized by using solar simulator under AM 1.5, 100mW/cm2 white light illumination and UV-Vis-NIR spectrophotometer respectively. From the current-voltage (I–V) measurement the result shows for 3 times of deposition, at thickness 719.413 nm gives the highest photoconductivity value, 35.2336×103 S.m−1. While for photoconductivity of 5, 7 and 10 times of deposition, there is no significant improvement were obtained. The optical properties were found to be strongly dependent on the thickness of nanocomposite thin films. The absorption coefficient reveals an improvement as the number of thickness increases with strong absorption at wavelength of 500 nm in visible ranges and 310 nm in UV ranges respectively.