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228 results on '"Mola, Genene Tessema"'

17. Enhanced Collection of Photocurrents Using Core–Shell Quantum Dots Decorated Polymer Composite Films

Author

Ogundele, Abiodun Kazeem and Mola, Genene Tessema

Abstract

Core–shell semiconductor quantum dots (SQDs) were synthesized via the microwave irradiation method from cadmium and zinc sulfides (CdxS/Zn1–xS). The SQDs were incorporated into the electron transport layer of thin film polymer solar cells (TFPSCs) to assist in light trapping and charge collection processes. The up and down conversion of radiation in SQDs is expected to boost absorption between the lower energy bandgap core and wide energy bandgap shell, respectively. The investigation employs apolymers blend consisting of a poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ehylhexyl)-carbonyl]thieno[3,4-b]thiophenediyl]]:[6,6]-phenyl C71butyric acid methyl ester (PTB7:PC71BM) as a photoactive medium of the solar cells. Consequently, the experimental evidence suggested that the inclusion of SQDs significantly improved the power conversion efficiency (PCE) of the solar cell as a result of increased energy transfer, exciton generation, and charge collection processes in TFPSCs. Furthermore, the performances of the solar cells are found to be dependent on the concentration of the SQD in the transport layer, where the highest PCE of 7.13% was measured at an optimal concentration of 0.375 wt %. This is an important development of the investigation with a recorded increment in PCE by nearly 23% from the reference cell.

Published
2024
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48. An Ultra-compact Plasmonic Modulator Using Elasto-optic Effect and Resonance Phenomena.

Author

Vaidya, Tanvi, Chauhan, Diksha, Mola, Genene Tessema, and Dwivedi, Ram Prakash

Subjects
PLASMONICS, RESONANCE effect, DIELECTRIC waveguides, OPTICAL modulation, REFRACTIVE index, SIMULATION software, DIELECTRICS
Abstract

We theoretically demonstrate an ultra-compact plasmonic modulator and switch of sub-micron size using elasto-optic effect with quite acceptable modulation ratio. The device is based on metal-dielectric-metal waveguide structure and uses resonance phenomena. The modulation mechanism originates by electrically changing thickness of dielectric layer made of elasto-optic material, which changes the effective refractive index of propagating optical mode. All the results are obtained using FEM simulation software. The seamless integration of optical beam modulation bears significant potential towards broadband, compact and efficient communication links and circuits. [ABSTRACT FROM AUTHOR]

Published
2023
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49. The impact of Ag/Co nanocomposite on organic charge transport medium for improved photocurrent in polymer solar cell.

Author

Ike, Jude N., Jili, Ncedo, Kumar, Amit, Sharma, Gaurav, and Mola, Genene Tessema

Subjects
COBALT, NANOCOMPOSITE materials, NANOPARTICLES, SOLAR cells, PHOTOCURRENTS
Abstract

Tuning charge transport properties using silver‐cobalt bimetallic nanoparticles is investigated to enhance the photo‐current collection in polymer solar cells. The silver‐cobalt nanoparticles were not only augmenting the charge transport processes but also expected to trap light by way of reflection. The polymers blend consisting of poly‐(3‐hexylthiophene) (P3HT):[6,6]‐phenyl C61 butyric acid methyl ester (PC61BM) is used in the fabrication of polymer solar cells. The experimental results indicated that the solar cells' performance depended on the concentration of Ag/Co in the hole transport layer (HTL). Nevertheless, the high‐power conversion efficiency value of up to 4.21% was observed, at the concentration of 0.1% by weight, which is much higher than pristine solar cells due to improved measured photocurrents from the devices. This is a significant improvement in PCE by 66.4% compared to the undoped transport medium. Ag/Co nanocomposite is found to be more stable under ambient laboratory conditions. [ABSTRACT FROM AUTHOR]

Published
2023
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