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Fahrenbruch, Alan L.; Bube, Richard H.

doi:10.1016/b978-0-12-247680-8.50011-6

Cited by 17 publications

(15 citation statements)

References 134 publications

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“…The decay rate of excitons R d ( x ) is assumed to be of the form R d ( x ) = x /τ x , where τ x is the average lifetime of exciton chosen such that the diffusion length of exciton is 10 nm. The term G ( r ) is assumed to be of the form G false( boldr false) = normal∑ i normalΦ i false( normalν i false) normalα i false( normalν i false) .25em exp [ − normalα i false( normalΔ − y false) ] where Φ i (ν i ) represents the frequency (ν i ) dependent incident photon flux . The incident power is obtained by summing over the intensities at different frequencies.…”

Section: Drift-diffusion Modeling Of Device Characteristicsmentioning

confidence: 99%

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Shah

Ganesan

2009

Macromolecules

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We present results obtained using a drift-diffusion model for the structure-property correlations in photovoltaic devices based on self-assembly of rod-coil block copolymers. We use a selfconsistent field theory model to generate the self-assembly morphologies of rod-coil block copolymers in confined situations. The density and orientational order parameter profiles so-obtained are then used as input to a recently proposed drift-diffusion model which predicts the photovoltaic device characteristics. The latter model allows for prescription of arbitrary morphologies of donor and acceptor phases while simultaneously incorporating the role of anisotropic charge transport of holes and excitons that arise in the ordered phases of rod-coil block copolymers. We present results elucidating the role of morphology of self-assembly, orientation of lamellar phases, domain widths, and the degree of phase separation and orientational ordering, upon the photovoltaic device characteristics.

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Section: Drift-diffusion Modeling Of Device Characteristicsmentioning

confidence: 99%

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Shah

Ganesan

2009

Macromolecules

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“…These high efficiency devices use CdTe in polycrystalline thin-film form as the active absorber layer. In polycrystalline photovoltaic (PV) materials, the electrical properties are often affected by the presence of two-dimensional grain boundaries due to (a) photogenerated carrier recombination and (b) charge trapping and obstruction of carrier transport by localized grain boundary states in the energy bands . Despite these effects, polycrystalline thin-film CdTe solar cells regularly outperform their single crystal counterparts .…”

Section: Introductionmentioning

confidence: 99%

Direct Observation of CdCl₂ Treatment Induced Grain Boundary Carrier Depletion in CdTe Solar Cells Using Scanning Probe Microwave Reflectivity Based Capacitance Measurements

Tuteja¹,

Koirala

Palekis

et al. 2016

J. Phys. Chem. C

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Device grade polycrystalline CdTe films, grown by rf-sputtering (yielding up to 13% efficient devices) and closespaced sublimation (CSS) (yielding up to 16% efficient devices), have been analyzed using scanning microwave impedance microscopy (sMIM). In order to study the effect of Cl on the electronic properties of grain boundaries in CdTe, sMIM based capacitance measurements were performed on the surfaces of asdeposited and CdCl 2 annealed CdTe films. The measurements were performed with an sMIM instrument operating at ∼3 GHz probe signal frequency in conjunction with a combination of ac and dc voltage biases applied to the tip. It was found that CdCl 2 annealed CdTe samples deposited using both CSS and sputtering exhibit carrier depletion along the grain boundaries as compared to the grain bulk. The grain boundary carrier depletion was not observed in samples that have not been CdCl 2 annealed and hence have no incorporated Cl.

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“…The charge collection is determined by the contribution of both drift- and diffusion-based components. The drift-based transport depends upon the electric field in the semiconductor; however, the charge carrier concentration in the semiconductor will define the diffusion-based transport. , The transport equation can be written as where D is the diffusion coefficient of charge carriers, n the carrier concentration, G the generation rate, μ the mobility, E the electric field in the x -direction, Δ n = n – n 0 the excess carrier concentration, t the time, and τ the carrier recombination lifetime. The first term in eq represents the diffusion component of charge transport.…”

mentioning

confidence: 99%

Correlation between Charge Transport Length Scales and Dielectric Relaxation Time Constant in Hybrid Halide Perovskite Semiconductors

2020

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The charge carrier diffusion length and dielectric relaxations are important parameters which decide the performance of various optoelectronic devices, in particular for photovoltaic devices. A comparative study is carried out on the charge transport length scale (L) for passivated and pristine CH3NH3PbI3 (MAPI) thin-film-based perovskite solar cells (PSCs) through scanning photocurrent microscopy (SPM). The SPM study suggested an improved L and degree of ambipolarity of photogenerated charge carriers (electron and hole) in passivated as compared to pristine MAPI-based PSCs. These results were found to be correlated with frequency-dependent photocurrent measurement, which shows that the relaxation time of the charge carrier is relatively lower in passivated MAPI-based PSCs. This mechanism could be explained by trap-assisted recombination, where trap states are induced by ion migration in halide perovskite films. Furthermore, passivation of traps showed an increased degree of ambipolarity in the perovskite semiconductor thin film.

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Junctions

Cited by 17 publications

References 134 publications

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Direct Observation of CdCl₂ Treatment Induced Grain Boundary Carrier Depletion in CdTe Solar Cells Using Scanning Probe Microwave Reflectivity Based Capacitance Measurements

Correlation between Charge Transport Length Scales and Dielectric Relaxation Time Constant in Hybrid Halide Perovskite Semiconductors

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Junctions

Cited by 17 publications

References 134 publications

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Correlations between Morphologies and Photovoltaic Properties of Rod−Coil Block Copolymers

Direct Observation of CdCl2 Treatment Induced Grain Boundary Carrier Depletion in CdTe Solar Cells Using Scanning Probe Microwave Reflectivity Based Capacitance Measurements

Correlation between Charge Transport Length Scales and Dielectric Relaxation Time Constant in Hybrid Halide Perovskite Semiconductors

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Direct Observation of CdCl₂ Treatment Induced Grain Boundary Carrier Depletion in CdTe Solar Cells Using Scanning Probe Microwave Reflectivity Based Capacitance Measurements