Quantum wells in photovoltaic cells

Rohr, Carsten; Connolly, J.P.; Bushnell, D.B.; Ballard, Ian; Abbott, Paul; Daukes, N J Ekins; Barnham, K.W.J.

doi:10.1201/9781420033861.ch5

Cited by 2 publications

(3 citation statements)

References 41 publications

(55 reference statements)

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“…The electronic properties of semiconductors can be tuned in strained-lattice devices − where a thin semiconductor film is grown epitaxially on a lattice larger than its native lattice. This narrows the bandgap and increases charge carrier mobilities.…”

Section: Introductionmentioning

confidence: 99%

Mechano-Electrochemistry and Fuel-Forming Mechano-Electrocatalysis on Spring Electrodes

Svedružić

Gregg

2014

J. Phys. Chem. C

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Each material, in principle, possesses a continuum of electrochemical and electrocatalytic properties that can be reversibly tuned by mechanical stress over its elastic range. As an initial test of this hypothesis we investigate stainless steel extension springs as electrodes. Stretching the springs reversibly doubles the heterogeneous rate constant for electron transfer to a redox species in solution, Ru(NH 3 ) 6 Cl 3 , while the charge transfer rate through a surface film of Ni(II/III) oxy-hydroxide increases ∼4-fold. Straining the springs near their elastic limit in 1 M NaOH increases the electrcatalytic hydrogen evolution current by ∼50% and the oxygen evolution current by ∼300%. Thus, even the small elastic strain (∼0.1% lattice deformation) that can be applied by stretching a spring leads to significant and reversible increases in the rates of: 1) electron transfer to a redox couple in solution, 2) charge transport through a surface film, and 3) electrocatalysis. ■ INTRODUCTIONA single material normally has just one set of electronic properties. However, if the material can be physically deformed by mechanical stressaltering its bond lengths and anglesits electronic structure will change accordingly. In principle, each material possesses a continuum of electronic properties that are reversibly tunable over its elastic range. This hypothesis builds on the ancient field of mechanochemistry which is currently enjoying a renaissance. Mechanochemistry includes any means of causing or promoting chemical reactions via mechanical force and its converse, generating mechanical force from chemical energy. 1−5 Some of the best known examples are found in living systems: hearing, touch, muscle contraction, cell motility, etc. Enzyme active sites, for example, are subject to both static and dynamic mechanical forces, and these may be essential for the catalytic process in some cases (the entatic state hypothesis). 6−13 The electronic properties of semiconductors can be tuned in strained-lattice devices 14−18 where a thin semiconductor film is grown epitaxially on a lattice larger than its native lattice. This narrows the bandgap and increases charge carrier mobilities. Qualitative changes, such as the transition from indirect-todirect bandgap in germanium, can also occur. 15,16 Strained metal monolayers are also obtained by growth on incommensurate substrates. These biaxially strained films show altered surface energetics and catalytic behavior. 19−21 In a similar vein, molecular catalysts are being synthesized with strained bonds to potentially improve their catalytic performance. 22−24 It should be possible to strain molecular catalysts and metal films dynamically and reversibly, although this has not yet been accomplished with molecular catalysts and has only recently been approached with metal and metal oxide films. 21 This capability would provide access to the entire spectrum of electronic properties available from each strained material, rather than just the few discrete data points we have now. Our initial ...

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Section: Introductionmentioning

confidence: 99%

Mechano-Electrochemistry and Fuel-Forming Mechano-Electrocatalysis on Spring Electrodes

Svedružić

Gregg

2014

J. Phys. Chem. C

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“…Calculation of efficiency of the novel PV cell with (5) and (4) shows an increase in efficiency of 17% and gives 17.5% instead 15% without the gold film. This result agrees well with the experimental data [20] where efficiency of organic solar cells, based on the bulk heterojunction system with silver nanoparticles, was increased by 17% as well.…”

Section: Discussionmentioning

confidence: 99%

“…Such chain ionization impact reaction exists in all semiconductors with very low efficiency. However, by this way, efficiency may be increased only using low-dimensional structures such as quantum wells [4], quantum dots [5], or nanocrystals of above 5 nm sizes [6]. Detailed analysis of low dimensional structures that are applicable for the solar light converting was done by Green [7].…”

Section: Introductionmentioning

confidence: 99%

Solar Cells Efficiency Increase Using Thin Metal Island Films

Axelevitch

Golan

2013

Journal of Solar Energy

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Metal nanodimension structures have multiple applications in modern technology. Noncontinuous thin island metal films of several types of metals deposited on dielectric or semiconductor surface introduce a unique behavior. In response to light exposure in certain range, the metal islands present a resonant absorption of light accompanied with a collective behavior of free electrons in these islands. In this paper, we present one of the possible ways to increase the efficiency of solar cells with metal islands imbedded in a semiconductor junction. Rough calculation was performed for a silicon solar cell and showed an increase of 17.5% in the overall efficiency of the cell.

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Quantum wells in photovoltaic cells

Cited by 2 publications

References 41 publications

Mechano-Electrochemistry and Fuel-Forming Mechano-Electrocatalysis on Spring Electrodes

Mechano-Electrochemistry and Fuel-Forming Mechano-Electrocatalysis on Spring Electrodes

Solar Cells Efficiency Increase Using Thin Metal Island Films

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