Role of Thickness towards the Optical and Electrical Properties of Photoactive Layer MEH-PPV: TiO2 Nanocomposite Thin Films

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.

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Tin instead of aluminum as a back electrode in P3HT:PC71BM organic solar cell

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac3a1f ◽

2021 ◽

Author(s):

Abdullah Almohammedi ◽

Yasser Abdelrady Masoud Ismail ◽

Mohd Taukeer Khan ◽

Mohamed Benghanem ◽

Saleh N Alamri ◽

...

Keyword(s):

Thin Films ◽

Solar Cells ◽

Solar Cell ◽

Electrical Properties ◽

Thermal Annealing ◽

Organic Solar Cells ◽

Organic Solar Cell ◽

Acid Methyl Ester ◽

Minor Effect ◽

Performance Parameters

Abstract In the present work, a thin film of tin (Sn) metal, instead of aluminum, was deposited as a back electrode, using thermal evaporation, for fabricating organic solar cell composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM). The effect of post-thermal annealing on performance parameters of the solar cell has been investigated at low temperatures (suitable for organic solar cells) up to 180 oC. In addition, effect of thermal annealing on morphological (using scanning electron microscopy) and electrical properties (using Hall Effect setup) of the Sn thin films was reported and discussed here. The obtained minor effect of the thermal annealing on morphological and electrical properties of Sn thin films is offset by an improvement in the performance parameters of solar cells after post-annealing at 160 oC. The present study shows good electrical properties of the Sn thin films which are comparable with those of aluminum thin films.

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Optical and electrical properties of solution processable TiOx thin films for solar cell and sensor applications

MRS Proceedings ◽

10.1557/opl.2011.1080 ◽

2011 ◽

Vol 1352 ◽

Author(s):

Jiguang Li ◽

Lin Pu ◽

Mool C. Gupta

Keyword(s):

Thin Film ◽

Thin Films ◽

Electrical Resistivity ◽

Refractive Index ◽

Solar Cells ◽

Solar Cell ◽

Electrical Properties ◽

Thermal Annealing ◽

Electrical Resistance ◽

Optical And Electrical Properties

ABSTRACTRecently, few tens of nanometer thin films of TiOx have been intensively studied in applications for organic solar cells as optical spacers, environmental protection and hole blocking. In this paper we provide initial measurements of optical and electrical properties of TiOx thin films and it’s applications in solar cell and sensor devices. The TiOx material was made through hydrolysis of the precursor synthesized from titanium isopropoxide, 2-methoxyethanol, and ethanolamine. The TiOx thin films of thickness between 20 nm to 120 nm were obtained by spin coating process. The refractive index of TiOx thin films were measured using an ellipsometric technique and an optical reflection method. At room temperature, the refractive index of TiOx thin film was found to be 1.77 at a wavelength of 600 nm. The variation of refractive index under various thermal annealing conditions was also studied. The increase in refractive index with high temperature thermal annealing process was observed, allowing the opportunity to obtain refractive index values between 1.77 and 2.57 at a wavelength 600 nm. The refractive index variation is due to the TiOx phase and density changes under thermal annealing.The electrical resistance was measured by depositing a thin film of TiOx between ITO and Al electrode. The electrical resistivity of TiOx thin film was found to be 1.7×107 Ω.cm as measured by vertical transmission line method. We have also studied the variation of electrical resistivity with temperature. The temperature coefficient of electrical resistance for 60 nm TiOx thin film was demonstrated as - 6×10-3/°C. A linear temperature dependence of resistivity between the temperature values of 20 – 100 °C was observed.The TiOx thin films have been demonstrated as a low cost solution processable antireflection layer for Si solar cells. The results indicate that the TiOx layer can reduce the surface reflection of the silicon as low as commonly used vacuum deposited Si3N4 thin films.

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STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF Al-DOPED ZnO TRANSPARENT CONDUCTING OXIDE FOR SOLAR CELL APPLICATIONS

Functional Materials Letters ◽

10.1142/s1793604711002330 ◽

2011 ◽

Vol 04 (04) ◽

pp. 401-405 ◽

Cited By ~ 5

Author(s):

W. CHER ◽

S. YICK ◽

S. XU ◽

Z. J. HAN ◽

K. OSTRIKOV

Keyword(s):

Thin Films ◽

Solar Cell ◽

Electrical Properties ◽

Transparent Conducting Oxide ◽

Optical Transmittance ◽

Nitrogen Atmosphere ◽

Optical And Electrical Properties ◽

Glass Substrates ◽

Optimal Annealing Temperature ◽

Post Synthesis

Al -doped zinc oxide (AZO) thin films are deposited onto glass substrates using radio-frequency reactive magnetron sputtering and the improvements in their physical properties by post-synthesis thermal treatment are reported. X-ray diffraction spectra show that the structure of films can be controlled by adjusting the annealing temperatures, with the best crystallinity obtained at 400°C under a nitrogen atmosphere. These films exhibit improved quality and better optical transmittance as indicated by the UV-Vis spectra. Furthermore, the sheet resistivity is found to decrease from 1.87 × 10-3 to 5.63 × 10-4Ω⋅cm and the carrier mobility increases from 6.47 to 13.43 cm2 ⋅ V-1 ⋅ s-1 at the optimal annealing temperature. Our results demonstrate a simple yet effective way in controlling the structural, optical and electrical properties of AZO thin films, which is important for solar cell applications.

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Effect Of Fluorine Doping On The Structural, Optical And Electrical Properties Of Spin Coated Tin Oxide Thin Films For Solar Cells Application

10.36293/sfj.2019.0002 ◽

2019 ◽

Keyword(s):

Thin Films ◽

Solar Cells ◽

Electrical Properties ◽

Tin Oxide ◽

Transparent Conducting Oxide ◽

Optical And Electrical Properties ◽

Fluorine Doping ◽

X Ray Diffraction ◽

X Ray ◽

Transparent Conducting

Transparent conducting oxide (TCO) thin films are materials of significance for their applications in optoelectronics and sun powered cells. Fluorine-doped tin oxide (FTO) is an elective material in the advancement of TCO films. This paper reports the impact of fluorine doping on structural, optical and electrical properties of tin oxide thin films for solar cells application. The sol-gel was prepared from anhydrous stannous chloride, SnCl2 as an originator, 2-methoxyethanol as a solvent, di-ethanolamine as a preservative and ammonium fluoride as the dopant source. FTO precursor solution was formulated to obtain 0, 5, 10, 15 and 20 % doping concentration and deposited on glass substrates by means of spin coater at the rate of 2000 rpm for 40 seconds. After pre-heated at 200 oC, the samples were annealed at 600 oC for 2 h. The structural, optical and electrical characteristics of prepared films were characterized using X-ray diffraction (XRD) analysis, UV-visible spectroscopy and electrical measurement. X-ray diffraction (XRD) investigation of the films demonstrated that the films were polycrystalline in nature with tetragonal-cassiterite structure with most extraordinary pinnacle having a grain size of 17.01 nm. Doping with fluorine decreases the crystallite size. There was increment in the absorbance of the film with increasing wavelength and the transmittance was basically reduced with increasing fluorine doping in the visible region. The energy band gaps were in the range of 4.106-4.121 eV. The sheet resistance were observed to decrease as the doping percentage of fluorine increased with exception at higher doping of 15 and 20 %. In view of these outcomes, FTO thin films prepared could have useful application in transparent conducting oxide electrode in solar cell.

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