scholarly journals Characterization of CuO/n-Si heterojunction solar cells produced by thermal evaporation

2018 ◽  
Vol 36 (4) ◽  
pp. 668-674 ◽  
Author(s):  
Reşit Özmenteş ◽  
Cabir Temirci ◽  
Abdullah Özkartal ◽  
Kadir Ejderha ◽  
Nezir Yildirim
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Thermal Evaporation ◽  
Front Surface ◽  
Band Gap Energy ◽  
Monoclinic Crystal ◽  
Photovoltaic Properties ◽  
X Ray ◽  
Heterojunction Solar Cells ◽  
Monoclinic Crystal Structure

AbstractCopper(II) oxide (CuO) in powder form was evaporated thermally on the front surface of an n-Si (1 0 0) single crystal using a vacuum coating unit. Structural investigation of the deposited CuO film was made using X-ray difraction (XRD) and energy dispersive X-ray analysis (EDX) techniques. It was determined from the obtained results that the copper oxide films exhibited single-phase CuO properties in a monoclinic crystal structure. Transmittance measurement of the CuO film was performed by a UV-Vis spectrophotometer. Band gap energy of the film was determined as 1.74 eV under indirect band gap assumption. Current-voltage (I-V) measurements of the CuO/n-Si heterojunctions were performed under illumination and in the dark to reveal the photovoltaic and electrical properties of the produced samples. From the I-V measurements, it was revealed that the CuO/n-Si heterojunctions produced by thermal evaporation exibit excellent rectifying properties in dark and photovoltaic properties under illumination. Conversion efficiencies of the CuO/n-Si solar cells are comparable to those of CuO/n-Si produced by other methods described in the literature.

Narrow band gap conjugated polymer for improving the photovoltaic performance of P3HT:PCBM ternary blend bulk heterojunction solar cells

2015 ◽  
Vol 6 (6) ◽  
pp. 962-972 ◽  
Author(s):  
M. G. Murali ◽  
Arun D. Rao ◽  
Sarita Yadav ◽  
Praveen C. Ramamurthy
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Conjugated Polymer ◽  
Narrow Band ◽  
Bulk Heterojunction ◽  
Photovoltaic Performance ◽  
Ternary Blend ◽  
Photovoltaic Properties ◽  
Heterojunction Solar Cells ◽  
Bulk Heterojunction Solar Cells

A new low band gap conjugated polymer PBDO-T-TDP is synthesized and used as a sensitizer in P3HT:PCBM based BHJ solar cells and its effect on their photovoltaic properties is investigated by blending them at various weight ratios.

Thermally Evaporated AgGaTe2 Thin Films For Low-Cost p-AgGaTe2/n-Si Heterojunction Solar Cells

2002 ◽  
Vol 744 ◽  
Author(s):  
Krishna C. Mandal ◽  
Anton Smirnov ◽  
Utpal N. Roy ◽  
Arnold Burger
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Photoelectron Spectroscopy ◽  
Antireflection Coating ◽  
Chalcopyrite Structure ◽  
Solar Simulator ◽  
Photovoltaic Properties ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Heterojunction Solar Cells

ABSTRACTHigh quality polycrystalline AgGaTe2 (AGT) thin films were deposited on H-terminated n-Si substrates by controlled thermal evaporation method at various substrate temperatures (300–500 K). X-ray diffraction (XRD) studies showed that all films were of chalcopyrite structure and while the films were deposited at 300 K had random grain orientation, the films deposited at higher substrate temperature (500 K) showed preferred (112) orientation. The composition of the films was thoroughly analyzed by energy dispersive x-ray analysis (EDAX) and by x-ray photoelectron spectroscopy (XPS) with and without argon ion etching. The ultraviolet-visible (UV-Vis) spectra showed the optical bandgap of 1.16 eV, with sharper band edge for the films deposited at higher temperature. The films were p-type and the resistivities of the as deposited at 300 and 500 K were 2.8 × 104 and 1.2 × 103 Ω. cm respectively. p-AgGaTe2/n-Si heterojunction solar cells, having an active area of 0.12 cm2 and without any antireflection coating, were fabricated. It was observed that the films deposited at 500 K produced junctions with improved photovoltaic properties. Under solar simulator AM1 illumination, the improved junctions exhibited an efficiency of 4.8% whereas the films deposited at 300 K showed an efficiency of 2.1%.

CuO Nanoparticles Based Bulk Heterojunction Solar Cells: Investigations on Morphology and Performance

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Aruna P. Wanninayake ◽  
Subhashini Gunashekar ◽  
Shengyi Li ◽  
Benjamin C. Church ◽  
Nidal Abu-Zahra
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Energy Gap ◽  
Bulk Heterojunction ◽  
Polymer Solar Cells ◽  
Band Gap Energy ◽  
Cuo Nanoparticles ◽  
Scanning Calorimetry ◽  
Heterojunction Solar Cells ◽  
And Performance

Copper oxide (CuO) is a p-type semiconductor having a band gap energy of 1.5 eV, which is close to the ideal energy gap of 1.4 eV required for solar cells to allow good solar spectral absorption. The inherent electrical characteristics of CuO nanoparticles make them attractive candidates for improving the performance of polymer solar cells (PSCs) when incorporated in the active polymer layer. The incorporation of CuO nanoparticles in P3HT/PC70BM solar cells at the optimum concentration yields 40.7% improvement in power conversion efficiency (PCE). The CuO nanoparticles in the size range of 100–150 nm have an effective average band gap of 2.07 eV. In addition, the X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses show improvement in P3HT crystallinity, and surface analysis by atomic force microscope (AFM) shows an increase in surface roughness of the PSCs. The key factors namely photo-absorption, exciton diffusion, dissociation, charge transport, and charge collection inside the PSCs which affect the external quantum efficiency (EQE) and PCE of these cells are analyzed.

scholarly journals Impact of fluorine substitution upon the photovoltaic properties of benzothiadiazole-fluorene alternate copolymers

RSC Advances ◽  
2015 ◽  
Vol 5 (57) ◽  
pp. 46386-46394 ◽  
Author(s):  
Luke Cartwright ◽  
Ahmed Iraqi ◽  
Yiwei Zhang ◽  
Tao Wang ◽  
David. G. Lidzey
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Bulk Heterojunction ◽  
Photovoltaic Properties ◽  
Fluorine Substitution ◽  
Heterojunction Solar Cells ◽  
Bulk Heterojunction Solar Cells ◽  
The Impact

The impact of replacing hydrogen with fluorine in efficient moderate-band gap alternating benzothiadiazole-fluorene copolymers is studied. The optical, electrochemical, thermal and photovoltaic properties in bulk heterojunction solar cells are investigated.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

Role of Surface Band Gap Widening in Cu(In, Ga)(Se, S)2 Thin-Films for the Photovoltaic Performance of ZnO/CdS/Cu(In, Ga)(Se, S)2 Heterojunction Solar Cells

2003 ◽  
Vol 763 ◽  
Author(s):  
U. Rau ◽  
M. Turcu
Keyword(s):  
Thin Films ◽  
Surface Layer ◽  
Solar Cells ◽  
Fermi Level ◽  
Band Gap ◽  
Photovoltaic Performance ◽  
Heterojunction Solar Cells ◽  
Fermi Level Pinning ◽  
Device Efficiency

AbstractNumerical simulations are used to investigate the role of the Cu-poor surface defect layer on Cu(In, Ga)Se2 thin-films for the photovoltaic performance of ZnO/CdS/Cu(In, Ga)Se2 heterojunction solar cells. We model the surface layer either as a material which is n-type doped, or as a material which is type-inverted due to Fermi-level pinning by donor-like defects at the interface with CdS. We further assume a band gap widening of this layer with respect to the Cu(In, Ga)Se2 bulk. This feature turns out to represent the key quality of the Cu(In, Ga)Se2 surface as it prevents recombination at the absorber/CdS buffer interface. Whether the type inversion results from n-type doping or from Fermi-level pinning is only of minor importance as long as the surface layer does not imply a too large number of excess defects in its bulk or at its interface with the normal absorber. With increasing number of those defects an n-type layer proofs to be less sensitive to material deterioration when compared to the type-inversion by Fermi-level pinning. For wide gap chalcopyrite solar cells the internal valence band offset between the surface layer and the chalcopyrite appears equally vital for the device efficiency. However, the unfavorable band-offsets of the ZnO/CdS/Cu(In, Ga)Se2 heterojunction limit the device efficiency because of the deterioration of the fill factor.

scholarly journals Size and Concentration Determination of Colloidal Nanocrystals by Small-Angle X-Ray Scattering

2018 ◽  
Author(s):  
Jorick Maes ◽  
Nicolo Castro ◽  
Kim De Nolf ◽  
Willem Walravens ◽  
Benjamin Abécassis ◽  
...  
Keyword(s):  
Band Gap ◽  
Small Angle ◽  
Accurate Determination ◽  
Band Gap Energy ◽  
Colloidal Nanocrystals ◽  
X Ray ◽  
Absolute Scale ◽  
X Ray Scattering ◽  
Ray Scattering

<div> <div> <div> <p>The accurate determination of the dimensions of a nano-object is paramount to the de- velopment of nanoscience and technology. Here, we provide procedures for sizing quasi- spherical colloidal nanocrystals (NCs) by means of small-angle x-ray scattering (SAXS). Using PbS NCs as a model system, the protocols outline the extraction of the net NC SAXS pattern by background correction and address the calibration of scattered x-ray intensity to an absolute scale. Different data analysis methods are compared, and we show that they yield nearly identical estimates of the NC diameter in the case of a NC ensemble with a monodisperse and monomodal size distribution. Extending the analysis to PbSe, CdSe </p> </div> </div> <div> <div> <p>and CdS NCs, we provide SAXS calibrated sizing curves, which relate the NC diameter and the NC band-gap energy as determined using absorbance spectroscopy. In compari- son with sizing curves calibrated by means of transmission electron microscopy (TEM), we systematically find that SAXS calibration assigns a larger diameter than TEM calibration to NCs with a given band gap. We attribute this difference to the difficulty of accurately sizing small objects in TEM images. To close, we demonstrate that NC concentrations can be directly extracted from SAXS patterns normalized to an absolute scale, and we show that SAXS-based concentrations agree with concentration estimates based on absorption spectroscopy.</p></div></div></div>

Sign in / Sign up

Export Citation Format

Share Document