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Solar cells

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Full-Text Articles in Physics

Solar Cells, D. Venkataraman Jan 2019

Solar Cells, D. Venkataraman

Science and Engineering Saturday Seminars

Solar cells convert the sun's energy into electrical energy. In this workshop, I will discuss the processes involved in solar cell and various types of solar cells that are being developed as an alternative to silicon solar cells. I will also demonstrate how students can build a solar cell from readily available materials.


Bandgap Profiling In Cigs Solar Cells Via Valence Electron Energy-Loss Spectroscopy, Julia I. Deitz, Shankar Karki, Sylvain X. Marsillac, Tyler J. Grassman Mar 2018

Bandgap Profiling In Cigs Solar Cells Via Valence Electron Energy-Loss Spectroscopy, Julia I. Deitz, Shankar Karki, Sylvain X. Marsillac, Tyler J. Grassman

Electrical & Computer Engineering Faculty Publications

A robust, reproducible method for the extraction of relative bandgap trends from scanning transmission electron microscopy (STEM) based electron energy-loss spectroscopy (EELS) is described. The effectiveness of the approach is demonstrated by profiling the bandgap through a CuIn1-xGaxSe2 solar cell that possesses intentional Ga/(In + Ga) composition variation. The EELS-determined bandgap profile is compared to the nominal profile calculated from compositional data collected via STEM-based energy dispersive X-ray spectroscopy. The EELS based profile is found to closely track the calculated bandgap trends, with only a small, fixed offset difference. This method, which is particularly advantageous ...


Zr-Doped Tio2 As A Thermostabilizer In Plasmon-Enhanced Dye-Sensitized Solar Cells, Anastasia Pasche, Bernd Grohe, Silvia Mittler, Paul A. Charpentier Sep 2017

Zr-Doped Tio2 As A Thermostabilizer In Plasmon-Enhanced Dye-Sensitized Solar Cells, Anastasia Pasche, Bernd Grohe, Silvia Mittler, Paul A. Charpentier

Physics and Astronomy Publications

Harvesting solar energy is a promising solution toward meeting the world’s evergrowing energy demand. Dye-sensitized solar cells (DSSCs) are hybrid organic–inorganic solar cells with tremendous potential for commercial application, but they are plagued by in efficiency due to their poor sunlight absorption. Plasmonic silver nanoparticles (AgNPs) have been shown to enhance the absorptive properties of DSSCs, but their plasmonic resonance can cause thermal damage resulting in cell deterioration. Hence, the influence of Zr-doped TiO2 on the efficiency of plasmon-enhanced DSSCs was studied, showing that 5 mol.% Zr-doping of the photoactive TiO2 material can improve the photovoltaic performance of ...


Band Offsets At The Interface Between Crystalline And Amorphous Silicon From First Principles, Karol Jarolimek, E. Hazrati, R. A. De Groot, D. A. De Wijs Jul 2017

Band Offsets At The Interface Between Crystalline And Amorphous Silicon From First Principles, Karol Jarolimek, E. Hazrati, R. A. De Groot, D. A. De Wijs

Center for Applied Energy Research Faculty Publications

The band offsets between crystalline and hydrogenated amorphous silicon (a−Si∶H) are key parameters governing the charge transport in modern silicon heterojunction solar cells. They are an important input for macroscopic simulators that are used to further optimize the solar cell. Past experimental studies, using x-ray photoelectron spectroscopy (XPS) and capacitance-voltage measurements, have yielded conflicting results on the band offset. Here, we present a computational study on the band offsets. It is based on atomistic models and density-functional theory (DFT). The amorphous part of the interface is obtained by relatively long DFT first-principles molecular-dynamics runs at an elevated temperature ...


Reflective Efficiencies Of Materials For Applications Of Bifacial Solar Cells, Michael Metter May 2016

Reflective Efficiencies Of Materials For Applications Of Bifacial Solar Cells, Michael Metter

Senior Theses

The bifacial solar cell is superior to its monofacial predecessor due to its ability to convert both incident light on top and reflected light from below into energy. The scattering of the reflected light is affected by the property of the material on which it is interacting. To date, little work has been contributed to studying the properties of these materials to determine optimal quantities for bifacial solar cells. In the first experiment, reflective efficiencies compared to the angle of reflection were explored for different grit of sandpaper in order to develop an understanding of how surface texture impacts reflectivity ...


Hybrid Type-I Inas/Gaas And Type-Ii Gasb/Gaas Quantum Dot Structure With Enhanced Photoluminescence, Hai-Ming Ji, Baolai Liang, Paul J. Simmonds, Bor-Chau Juang, Tao Yang, Robert J. Young, Diana L. Huffaker Apr 2015

Hybrid Type-I Inas/Gaas And Type-Ii Gasb/Gaas Quantum Dot Structure With Enhanced Photoluminescence, Hai-Ming Ji, Baolai Liang, Paul J. Simmonds, Bor-Chau Juang, Tao Yang, Robert J. Young, Diana L. Huffaker

Paul J. Simmonds

We investigate the photoluminescence (PL) properties of a hybrid type-I InAs/GaAs and type-II GaSb/GaAs quantum dot (QD) structure grown in a GaAs matrix by molecular beam epitaxy. This hybrid QD structure exhibits more intense PL with a broader spectral range, compared with control samples that contain only InAs or GaSb QDs. This enhanced PL performance is attributed to additional electron and hole injection from the type-I InAs QDs into the adjacent type-II GaSb QDs. We confirm this mechanism using time-resolved and power-dependent PL.These hybrid QD structures show potential for high efficiency QD solar cell applications.


Graphene-Semiconductor Heterojunctions And Devices, Tzu-Min Ou Apr 2015

Graphene-Semiconductor Heterojunctions And Devices, Tzu-Min Ou

Electrical, Computer & Energy Engineering Graduate Theses & Dissertations

In this thesis we explore the potential of versatile graphene-semiconductor heterojunctions in photodetection and field-effect transistor (FET) applications. The first part of the thesis studies near-infrared photodiode (NIR PD) based on a graphene- n-Si heterojunction in which graphene is used as the absorbing medium. Graphene is chosen for its absorption in NIR wavelengths to which Si is not responsive. Most graphene detectors in the literature are photoconductors that have a high dark current. The graphene-Si heterojunction PD has a large Schottky barrier height that suppresses the dark current and enhances the current rectification and the photon detectivity.

The fabricated graphene-Si ...


Hybrid Type-I Inas/Gaas And Type-Ii Gasb/Gaas Quantum Dot Structure With Enhanced Photoluminescence, Hai-Ming Ji, Baolai Liang, Paul J. Simmonds, Bor-Chau Juang, Tao Yang, Robert J. Young, Diana L. Huffaker Mar 2015

Hybrid Type-I Inas/Gaas And Type-Ii Gasb/Gaas Quantum Dot Structure With Enhanced Photoluminescence, Hai-Ming Ji, Baolai Liang, Paul J. Simmonds, Bor-Chau Juang, Tao Yang, Robert J. Young, Diana L. Huffaker

Physics Faculty Publications and Presentations

We investigate the photoluminescence (PL) properties of a hybrid type-I InAs/GaAs and type-II GaSb/GaAs quantum dot (QD) structure grown in a GaAs matrix by molecular beam epitaxy. This hybrid QD structure exhibits more intense PL with a broader spectral range, compared with control samples that contain only InAs or GaSb QDs. This enhanced PL performance is attributed to additional electron and hole injection from the type-I InAs QDs into the adjacent type-II GaSb QDs. We confirm this mechanism using time-resolved and power-dependent PL.These hybrid QD structures show potential for high efficiency QD solar cell applications.


Atmospheric Pressure Chemical Vapor Deposition Of Functional Oxide Materials For Crystalline Silicon Solar Cells, Kristopher Davis Jan 2015

Atmospheric Pressure Chemical Vapor Deposition Of Functional Oxide Materials For Crystalline Silicon Solar Cells, Kristopher Davis

Electronic Theses and Dissertations

Functional oxides are versatile materials that can simultaneously enable efficiency gains and cost reductions in crystalline silicon (c-Si) solar cells. In this work, the deposition of functional oxide materials using atmospheric pressure chemical vapor deposition (APCVD) and the integration of these materials into c-Si solar cells are explored. Specifically, thin oxide films and multi-layer film stacks are utilized for the following purposes: (1) to minimize front surface reflectance without increasing parasitic absorption within the anti-reflection coating(s); (2) to maximize internal back reflectance of rear passivated cells, thereby increasing optical absorption of weakly absorbed long wavelength photons (? > 900 nm); (3 ...


Electron And Hole Drift Mobility Measurements On Thin Film Cdte Solar Cells, Qi Long, Steluta A. Dinca, Eric A. Schiff, Ming Yu, Jeremy Theil Jul 2014

Electron And Hole Drift Mobility Measurements On Thin Film Cdte Solar Cells, Qi Long, Steluta A. Dinca, Eric A. Schiff, Ming Yu, Jeremy Theil

Physics

We report electron and hole drift mobilities in thin film polycrystalline CdTe solar cells based on photocarrier time-of-flight measurements. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range of 10–100 cm2/Vs, and holes are in the range of 1–10 cm2/Vs. The electron drift mobilities are about a thousand times smaller than those measured in single crystal CdTe with time-of-flight; the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl2; treatment had little effect ...


Manufacture And Investigation Of Organic Composite Polymer Based Films For Advanced Flexible Solar Cells, Raffie Arshak Dec 2013

Manufacture And Investigation Of Organic Composite Polymer Based Films For Advanced Flexible Solar Cells, Raffie Arshak

Masters

Modern society has created big challenges in the area of sustainable supply of energy to satisfy the needs of growing population and to account for depleting fossil fuel resources. The Irish Government has set targets for the energy sector by 2020, with 33% of electricity to be generated from renewable sources. Organic photovoltaic devices offer several advantages over expensive silicon solar cells, including deposition of ultra-thin films by spin-coating, printing and spray-coating. This in turn provides for the exciting possibility to make lightweight, flexible solar cells for a broad range of existing and emerging applications for security, military and medicine ...


Photothermal Deflection Spectroscopy Of Amorphous, Nanostructured And Nanocomposite Thin Films, Muhammad Shafiq Ahmed Oct 2013

Photothermal Deflection Spectroscopy Of Amorphous, Nanostructured And Nanocomposite Thin Films, Muhammad Shafiq Ahmed

Electronic Thesis and Dissertation Repository

The energy needs of the modern world are growing day by day, while sources of non-renewable fossil fuels are limited, so there is a need to efficiently use the existing resources and explore renewable energy sources. In order to harvest, store and efficiently utilize renewable energy, we need to explore new materials and improve the performance of existing ones. Among others, hydrogenated amorphous silicon (a-Si:H) with high optical absorption in the visible range of electromagnetic spectrum, is a low cost material for solar cells. But the efficiency of such solar cells is comparatively low because of intrinsic defects associated ...


Investigations Into B-O Defect Formation-Dissociation In Cz-Silicon And Their Effect On Solar Cell Performance, Prakash M. Basnyat May 2013

Investigations Into B-O Defect Formation-Dissociation In Cz-Silicon And Their Effect On Solar Cell Performance, Prakash M. Basnyat

Dissertations

About 30% of the total market share of industrial manufacture of silicon solar cells is taken by single crystalline Czochralski (CZ) grown wafers. The efficiency of solar cells fabricated on boron-doped Czochralski silicon degrades due to the formation of metastable defects when excess electrons are created by illumination or minority carrier injection during forward bias. The recombination path can be removed by annealing the cell at about 200° C but recombination returns on exposure to light.

Several mono-crystalline and multi-crystalline solar cells have been characterized by methods such as laser beam induced current (LBIC), Four-Probe electrical resistivity etc. to better ...


Plasmonic Nanostructures For The Absorption Enhancement Of Silicon Solar Cells, Nathan Matthias Burford May 2013

Plasmonic Nanostructures For The Absorption Enhancement Of Silicon Solar Cells, Nathan Matthias Burford

Theses and Dissertations

In this work, computational investigation of plasmonic nanostructures was conducted using the commercial finite element electromagnetics solver Ansys® HFSS. Arrays of silver toroid nanoparticles located on the surface of an amorphous silicon thin-film absorbing layer were studied for particle sizes ranging from 20 nm to 200 nm in outer diameter. Parametric optimization by calculating an approximation of the photocurrent enhancement due to the nanoparticles was performed to determine optimal surface coverage of the nanoparticles. A comparison was made between these optimized nanotoroid arrays and optimized nanosphere arrays based on spectral absorption enhancement and potential photocurrent enhancement in an amorphous silicon ...


Making Solar Cells, D. Venkataraman Jan 2013

Making Solar Cells, D. Venkataraman

Nanotechnology Teacher Summer Institutes

Overview of solar energy and photovoltaic cells. Making a cuprous oxide cell activity.


Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Systems, Marco Olguin Jan 2013

Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Systems, Marco Olguin

Open Access Theses & Dissertations

The present research involves the study of donor-acceptor (D/A) dyad complexes from a charge transfer energy perspective. The aim is to provide insight and predictive understanding into the charge transfer processes of the molecular-level components in donor-acceptor based organic solar cells using computational methods to describe photochemical processes at the quantum mechanical level within the Density Functional Theory (DFT) approximation. Predictive understanding is anchored in reproducing experimental results, wherein the present work a perturbative excited-state DFT method is described in detail and shown to give Charge Transfer (CT) energies in excellent agreement with benchmark experimental data. With an accurate ...


Extension To Pv Optics To Include Front Electrode Design In Solar Cells, Debraj Guhabiswas Dec 2012

Extension To Pv Optics To Include Front Electrode Design In Solar Cells, Debraj Guhabiswas

Dissertations

Proper optical designing of solar cells and modules is of paramount importance towards achieving high photovoltaic conversion efficiencies. Modeling softwares such as PV OPTICS, BIRANDY and SUNRAYS have been created to aid such optical designing of cells and modules; but none of these modeling packages take the front metal electrode architecture of a solar cell into account.

A new model, has been developed to include the front metal electrode architecture to finished solar cells for optical calculations. This has been implemented in C++ in order to add a new module to PV OPTICS (NREL’s photovoltaic modeling tool) to include ...


Plasmonic And Photonic Designs For Light Trapping In Thin Film Solar Cells, Liming Ji Dec 2012

Plasmonic And Photonic Designs For Light Trapping In Thin Film Solar Cells, Liming Ji

Theses and Dissertations

Thin film solar cells are promising to realize cheap solar energy. Compared to conventional wafer cells, they can reduce the use of semiconductor material by 90%. The efficiency of thin film solar cells, however, is limited due to insufficient light absorption. Sufficient light absorption at the bandgap of semiconductor requires a light path more than 10x the thickness of the semiconductor. Advanced designs for light trapping are necessary for solar cells to absorb sufficient light within a limited volume of semiconductor. The goal is to convert the incident light into a trapped mode in the semiconductor layer.

In this dissertation ...


Investigation Of Vopcpho As An Acceptor Material For Bulk Heterojunction Solar Cells, Shahino Mah Abdullah Aug 2012

Investigation Of Vopcpho As An Acceptor Material For Bulk Heterojunction Solar Cells, Shahino Mah Abdullah

Shahino Mah Abdullah

In this study, we have successfully demonstrated a new system of donor–acceptor blend for bulk heterojunction solar cells of poly(3-hexylthiophene) (P3HT) by using vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO) as acceptor material. A broad absorption over the whole visible range (450–750 nm) is achieved. Utilizing this blend system in solar cell fabrication, ITO/PEDOT:PSS/P3HT:VOPcPhO/Al solar cells have been fabricated and characterized in open air. A maximum power conversation efficiency up to 1.09% has been recorded. To confirm the charge transport, the electron and hole mobility of VoPcPhO has been measured. The ...


Electron Drift-Mobility Measurements In Polycrystalline Cuin1-Xgaxse2 Solar Cells, Steluta A. Dinca, Eric A. Schiff, William N. Shafarman, Brian Egaas, Rommel Noufi, David L. Young Mar 2012

Electron Drift-Mobility Measurements In Polycrystalline Cuin1-Xgaxse2 Solar Cells, Steluta A. Dinca, Eric A. Schiff, William N. Shafarman, Brian Egaas, Rommel Noufi, David L. Young

Physics

We report photocarrier time-of-flight measurements of electron drift mobilities for the p-type CuIn1-xGaxSe2 films incorporated in solar cells. The electron mobilities range from 0.02 to 0.05 cm^2/Vs and are weakly temperature-dependent from 100–300 K. These values are lower than the range of electron Hall mobilities (2-1100 cm2/Vs) reported for n-type polycrystalline thin films and single crystals. We propose that the electron drift mobilities are properties of disorder-induced mobility edges and discuss how this disorder could increase cell efficiencies.


Properties Of Cu(In,Ga) Se2 Thin Films And Solar Cells Deposited By Hybrid Process, S. Marsillac, H. Khatri, K. Aryal, R. W. Collins Feb 2012

Properties Of Cu(In,Ga) Se2 Thin Films And Solar Cells Deposited By Hybrid Process, S. Marsillac, H. Khatri, K. Aryal, R. W. Collins

Electrical & Computer Engineering Faculty Publications

Cu(In,Ga)Se-2 solar cells were fabricated using a hybrid cosputtering/evaporation process, and efficiencies as high as 12.4% were achieved. The films were characterized by energy-dispersive X-ray spectroscopy, glancing incidence X-ray diffraction, scanning electron microscopy, auger electron spectroscopy, and transmittance and reflectance spectroscopy, and their properties were compared to the ones of films deposited by coevaporation. Even though the films were relatively similar, the ones deposited by the hybrid process tend to have smaller grains with a slightly preferred orientation along the (112) axis and a rougher surface. Both types of films have uniform composition through the ...


Fundamental Properties Of Functional Zinc Oxide Nanowires Obtained By Electrochemical Method And Their Device Applications, Athavan Nadarajah Jan 2012

Fundamental Properties Of Functional Zinc Oxide Nanowires Obtained By Electrochemical Method And Their Device Applications, Athavan Nadarajah

Dissertations and Theses

We report on the fundamental properties and device applications of semiconductor nanoparticles. ZnO nanowires and CdSe quantum dots were used, prepared, characterized, and assembled into novel light-emitting diodes and solar cells. ZnO nanowire films were grown electrochemically using aqueous soluble chloride-based electrolytes as precursors at temperatures below 90° C. Dopants were added to the electrolyte in the form of chloride compounds, which are AlCl3, CoCl2, CuCl2, and MnCl2. The optical, magnetic, and structural properties of undoped and transition-metal-ion doped ZnO nanowires were explored. Our results indicate that the as-grown nanowire structures have considerable internal strain, resulting ...


Thermodynamic Limit To Photonic-Plasmonic Light-Trapping In Thin Films On Metals, Eric A. Schiff Nov 2011

Thermodynamic Limit To Photonic-Plasmonic Light-Trapping In Thin Films On Metals, Eric A. Schiff

Physics

We calculate the maximum optical absorptance enhancements in thin semiconductor films on metals due to structures that diffuse light and couple it to surface plasmon polaritons. The calculations can be used to estimate plasmonic effects on light-trapping in solar cells. The calculations are based on the statistical distribution of energy in the electromagnetic modes of the structure, which include surface plasmon polariton modes at the metal interface as well as the trapped waveguide modes in the film. The enhancement has the form 4n2+/h (n – film refractive index, λ – optical wavelength, h – film thickness), which is an ...


Molecular Beam Epitaxy Of Metamorphic InYGa1−YP Solar Cells On Mixed Anion GaasXP1−X/Gaas Graded Buffers, Stephanie Tomasulo, John Simon, Paul J. Simmonds, Jonathan Biagiotti, Minjoo L. Lee Apr 2011

Molecular Beam Epitaxy Of Metamorphic InYGa1−YP Solar Cells On Mixed Anion GaasXP1−X/Gaas Graded Buffers, Stephanie Tomasulo, John Simon, Paul J. Simmonds, Jonathan Biagiotti, Minjoo L. Lee

Paul J. Simmonds

The authors have grown metamorphic InyGa1−yP on optimized GaAsxP1−x/GaAs graded buffers via solid source molecular beam epitaxy(MBE) for multijunction solar cell applications. In this work, the authors show that a previously developed kinetic growth model can be used to predict the composition of mixed anion GaAsxP1−x alloys on GaAs as a function of substrate temperature and group-V flux. The advantages of using a high growth temperature of 700 °C are then described, including the minimized dependence of composition on small temperature variations, a linear dependence ...


Scanning Capacitance Spectroscopy On N+-P Asymmetrical Junctions In Multicrystalline Si Solar Cells, Chun-Sheng Jiang, Jennifer T. Heath, Helio R. Moutinho, Mowafak M. Al-Jassim Jan 2011

Scanning Capacitance Spectroscopy On N+-P Asymmetrical Junctions In Multicrystalline Si Solar Cells, Chun-Sheng Jiang, Jennifer T. Heath, Helio R. Moutinho, Mowafak M. Al-Jassim

Faculty Publications

We report on a scanning capacitance spectroscopy (SCS) study on the n+-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in the literature ...


Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani Jan 2011

Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani

Electronic Theses and Dissertations

Metal nano particles are investigated as scattering centers on front surface of thin-film solar cells to improve efficiency. The principle is that scattering, which is enhanced near the plasmon resonance frequency of the particle and depends on particle size, increases the effective optical path length of incident light, leading to more light absorption in active layer of thin film solar cell. The particular types of particles investigated here are known as "metal-black", well known as an IR absorber for bolometric infrared detectors. Gold-black was deposited on commercial thin-film solar cells using a thermal evaporator in a nitrogen ambient at pressures ...


Metamorphic Gaasp Buffers For Growth Of Wide-Bandgap Ingap Solar Cells, J. Simon, S. Tomasulo, P. J. Simmonds, M. Romero, M. L. Lee Dec 2010

Metamorphic Gaasp Buffers For Growth Of Wide-Bandgap Ingap Solar Cells, J. Simon, S. Tomasulo, P. J. Simmonds, M. Romero, M. L. Lee

Paul J. Simmonds

GaAsxP1−x graded buffers were grown via solid source molecular beam epitaxy(MBE) to enable the fabrication of wide-bandgap InyGa1−yP solar cells. Tensile-strained GaAsxP1−x buffers grown on GaAs using unoptimized conditions exhibited asymmetric strain relaxation along with formation of faceted trenches, 100–300 nm deep, running parallel to the [011] direction. We engineered a 6 μm thick grading structure to minimize the faceted trench density and achieve symmetric strain relaxation while maintaining a threading dislocation density of ≤106 cm−2. In comparison, compressively-strained graded GaAsx ...


Pulsed Laser Deposition Of Graphite Counter Electrodes For Dye-Sensitized Solar Cells, Krishna P. Acharya, Himal Khatri, Sylvain Marsillac, Bruno Ullrich, Pavel Anzenbacher, Mikhail Zamkov Nov 2010

Pulsed Laser Deposition Of Graphite Counter Electrodes For Dye-Sensitized Solar Cells, Krishna P. Acharya, Himal Khatri, Sylvain Marsillac, Bruno Ullrich, Pavel Anzenbacher, Mikhail Zamkov

Electrical & Computer Engineering Faculty Publications

We report on pulsed laser deposition of graphite onto flexible plastic and conductive glass substrates for use as a counter electrode in dye-sensitized solar cells. The efficiency of as-prepared graphite electrodes was tested using CdS-sensitized solar cell architecture resulting in external quantum efficiency comparable to that of conventional platinum counter electrodes. This work highlights the possibility of using pulsed laser deposited graphite as a low-cost alternative to platinum, which could be fabricated both on flexible and rigid substrates.


Design Of Organic Tandem Solar Cells Using Pcpdtbt: Pc61 Bm And P3ht: Pc71bm, Gon Namkoong, Patrick Boland, Keejoo Lee, James Dean Jan 2010

Design Of Organic Tandem Solar Cells Using Pcpdtbt: Pc61 Bm And P3ht: Pc71bm, Gon Namkoong, Patrick Boland, Keejoo Lee, James Dean

Electrical & Computer Engineering Faculty Publications

We conducted optical and electrical simulations with the goal of determining the optimal design for conjugated polymer-fullerene tandem solar cells using poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta[2,1- b;3,4- b′] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT): [6,6]-phenyl C61 butyric acid methyl ester (PC61 BM) as a bottom cell and poly(3-hexylthiophene) (P3HT): [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as a top cell. The effects of photon density, absorption, balanced and unbalanced charge carrier transport, and bimolecular recombination in the two subcells were incorporated into the ...


Nanowire Solar Cell Sensitized With Ii-Vi Quantum Dot Layer, Athavan Nadarajah, Robert Campbell Word, Kaitlyn Vansant, Rolf Könenkamp Jan 2008

Nanowire Solar Cell Sensitized With Ii-Vi Quantum Dot Layer, Athavan Nadarajah, Robert Campbell Word, Kaitlyn Vansant, Rolf Könenkamp

Physics Faculty Publications and Presentations

We report first results on a new solar cell consisting of a p-i-n hetero-junction formed between n-type transparent nanowires, undoped semiconductor quantum dots and a wide bandgap p-type polymer layer. The overall structure is SnO2/ZnO/CdSe/MEH-PPV with MEH-PPV standing for poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene]. Microscopic studies on the structure of the quantum dot layer before and after anneal indicates a morphology change from a quantum dot assembly to a continuous polycrystalline thin film. The charge transfer between the absorber layer and the adjacent layers is improved as the layer is converted from the quantum dot ...