Atomic and electronic structure of perfect dislocations in the solar absorber materials 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">CuInSe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
 and 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">CuGaSe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
 studied by first-principles calculations

Barragan-Yani, Daniel; Albe, Karsten

doi:10.1103/physrevb.95.115203

“…This appears to be very unlikely, taking into account that grain boundaries appear as active recombination centers whereas dislocations do not quench the luminescence [144]. Deep defects have been predicted to form in dislocations around an energy of about 0.5 eV above the valence band [145], which is not in agreement with the defect energy of the DS state. We therefore assign the DS state tentatively to a point defect, namely, the Cu III −1/−2 state, keeping in mind that this assignment does not provide a good explanation as to why the density of states should be so broad.…”

Section: B Deep Defectsmentioning

confidence: 96%

Electronic defects in Cu(In,Ga)Se2 : Towards a comprehensive model

Spindler

¹

,

Babbe

²

,

Wolter

³

et al. 2019

Phys. Rev. Materials

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The electronic defects in any semiconductor play a decisive role for the usability of this material in an optoelectronic device. Electronic defects determine the doping level as well as the recombination centers of a solar cell absorber. Cu(In, Ga)Se 2 is used in thin-film solar cells with high and stable efficiencies. The electronic defects in this class of materials have been studied experimentally by photoluminescence, admittance, and photocurrent spectroscopies for many decades now. The literature results are summarized and compared to new results by photoluminescence of deep defects. These observations are related to other experimental methods that investigate the physicochemical structure of defects. To finally assign the electronic defect signatures to actual physicochemical defects, a comparison with theoretical predictions is necessary. In recent years the accuracy of these calculations has greatly improved by the use of hybrid functionals. A comprehensive model of the electronic defects in Cu(In, Ga)Se 2 is proposed based on experiments and theory. The consequences for solar cell efficiency are discussed.

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“…The Burgers vectors were identified as 1/4 [ 201] and 1/2 [110] [21,47], while the dislocation cores (equal to the top atomic lines of the introduced half planes) consist of either only Se ions or only cations [48], Cu depletion within an approximately 3 nm wide region around a dislocation core was measured by means of atom-probe tomography (APT) [48]. A recent ab-initio study on full dislocations in CuInSe 2 and CuGaSe 2 [49] does not indicate any deep defect states associated to most of the 60° dislocation configurations.…”

Section: Dislocations and Partial Dislocationsmentioning

confidence: 99%

Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se₂ thin films for solar cells – a review

Abou‐Ras

¹

,

Schmidt

²

,

Schäfer

³

et al. 2016

Physica Rapid Research Ltrs

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The present review gives an overview of the various reports on properties of line and planar defects in Cu(In,Ga)(S,Se)2 thin films for high‐efficiency solar cells. We report results from various analysis techniques applied to characterize these defects at different length scales, which allow for drawing a consistent picture on structural and electronic defect properties. A key finding is atomic reconstruction detected at line and planar defects, which may be one mechanism to reduce excess charge densities and to relax deep‐defect states from midgap to shallow energy levels. On the other hand, nonradiative Shockley–Read–Hall recombination is still enhanced with respect to defect‐free grain interiors, which is correlated with substantial reduction of luminescence intensities. Comparison of the microscopic electrical properties of planar defects in Cu(In,Ga)(S,Se)2 thin films with two‐dimensional device simulations suggest that these defects are one origin of the reduced open‐circuit voltage of the photovoltaic devices. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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“…For example, Bader charge analysis is frequently used to understand redox processes and related phenomena in intercalation battery cathodes [6][7][8][9] . Charge densities are critical for solar cell materials properties as well 10,11 . Similarly, charge density redistribution is often used to understand trends in catalytic activity [12][13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Equivariant graph neural networks for fast electron density estimation of molecules, liquids, and solids

Jørgensen

¹

,

Bhowmik

²

2022

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Electron density $$\rho (\overrightarrow{{{{\bf{r}}}}})$$ ρ ( r → ) is the fundamental variable in the calculation of ground state energy with density functional theory (DFT). Beyond total energy, features and changes in $$\rho (\overrightarrow{{{{\bf{r}}}}})$$ ρ ( r → ) distributions are often used to capture critical physicochemical phenomena in functional materials. We present a machine learning framework for the prediction of $$\rho (\overrightarrow{{{{\bf{r}}}}})$$ ρ ( r → ) . The model is based on equivariant graph neural networks and the electron density is predicted at special query point vertices that are part of the message-passing graph, but only receive messages. The model is tested across multiple datasets of molecules (QM9), liquid ethylene carbonate electrolyte (EC) and LixNiyMnzCo(1-y-z)O2 lithium ion battery cathodes (NMC). For QM9 molecules, the accuracy of the proposed model exceeds typical variability in $$\rho (\overrightarrow{{{{\bf{r}}}}})$$ ρ ( r → ) obtained from DFT done with different exchange-correlation functionals. The accuracy on all three datasets is beyond state of the art and the computation time is orders of magnitude faster than DFT.

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Atomic and electronic structure of perfect dislocations in the solar absorber materials CuInSe2 and CuGaSe2 studied by first-principles calculations

Cited by 8 publications

References 41 publications

Electronic defects in Cu(In,Ga)Se2 : Towards a comprehensive model

Electronic defects in Cu(In,Ga)Se2 : Towards a comprehensive model

Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se₂ thin films for solar cells – a review

Equivariant graph neural networks for fast electron density estimation of molecules, liquids, and solids

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Atomic and electronic structure of perfect dislocations in the solar absorber materials CuInSe2 and CuGaSe2 studied by first-principles calculations

Cited by 8 publications

References 41 publications

Electronic defects in Cu(In,Ga)Se2 : Towards a comprehensive model

Electronic defects in Cu(In,Ga)Se2 : Towards a comprehensive model

Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se2 thin films for solar cells – a review

Equivariant graph neural networks for fast electron density estimation of molecules, liquids, and solids

Contact Info

Product

Resources

About

Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se₂ thin films for solar cells – a review