Effects of Copper Substitution by Alkali Metals on the Properties of Chalcopyrites for Tandem Applications: Insights from Theory (original) (raw)
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Journal of Physics and Chemistry of Solids, 2005
The amazing opto-electronic properties of pseudo-ternaries Cu(In,Ga)(S,Se) 2 compounds are, for a great deal, related to their defect chemistry, for which ab initio calculation have already provided new insights. As Indium and Gallium are rare and expensive elements, the search of an alternative may become an important issue. Ab initio calculation of energies and electronic structures of various chalcopyrite type structures replacing In by other elements has been performed exploring over 16 compounds with some 10 different elements of the periodic table. Among the different possibilities, the substitution of In by the isoelectronic couples such as (Zn, Sn) and other cationic couples having an average valency of III have been evaluated in details, as well as the influence of the anion (S or Se). The most important point defects and defect complexes have been explored. Low copper vacancy (V Cu ) and defect complexes (such as V Cu CZn Cu ) formation energies have been found in these new compounds: for instance the formation energy of V Cu in Cu 2 SnZnSe 4 is 0.49 eV as compared to 0.48 eV in CuInSe 2 (CIS). In addition to point defect characteristics, different electronic properties (such as band structure, bonding character) are compared to the one of CIS, which is considered as our reference structure. The method used is based on the density functional theory within the framework of pseudo-potentials and plane waves basis. The results are discussed in view of the existing data, models and calculations. Based on these properties as well as the ionic/covalent bonding character some trends are exposed. q
2010_TFCE_44_4_384_Experiment_Verification.pdf
The composition of complex compounds, from the solutions of which the electrodeposition of Ag-Cu, Cu-Co, and Bi-Co alloys and Fe as a multivalent metal is possible or impossible, is predicted on the basis of a stochastic model for choosing ligands that makes it possible to determine the allowable range of the values of the stability constants of complexes, the reduction of which occurs with the formation of an alloy. The reliability of the prediction and, consequently, the adequacy of the stochastic model for choosing ligands are experimentally verified.
AN ABSTRACT OF THE THESIS OF Robert Kykyneshi for the degree of Master of Science in Physics
2011
approved: Bulk properties of CuSc1..MgO2, CuSci..MgO2+, BaCu2S2, Bai..KCu2S2, BaCu2Se2 and Bai.KCu2Se2 are investigated supporting the search for highly conductive p-type thin films. Mg is an efficient dopant in CuScO2 with conductivity up to l.5.102 S/cm. Oxidation of CuScO2:Mg leads to further increase in conductivity up to 0.5 S/cm. The amount of oxygen entering the material is dependent on the Mg content with an observed maximum of y=0.23 in the 5 at. % Mg doped sample. Mg doping above 6 at. % leads to saturated or slightly decreased conductivities in CuScO2. In the case of BaCu2S2:K and BaCu2Se2:K, conductivities of 420 S/cm and 740 S/cm are achieved at room temperature with 10 at. % potassium doping with no observable saturation, 2 orders of magnitude higher than in the corresponding undoped forms. A change from activated to metallic type conduction mechanism is observed in Bai.KCu2S2 at x>0.005. The Seebeck effect measurements demonstrate p-type conductivity for all sample...
Thin Solid Films, 2017
The present contribution is a summary of an event that was organized as a special evening session in Symposium V "Chalcogenide Thin-Film Solar Cells" at the E-MRS 2016 Spring Meeting, Lille, France. The presentations in this session were given by the coauthors of this paper. These authors present retrospectives of key developments in the field of Cu(In,Ga)(S,Se) 2 solar cells as they themselves had witnessed in their laboratories or companies. Also, anecdotes are brought up, which captured interesting circumstances in that evolutionary phase of the field. Because the focus was on historical perspectives rather than a comprehensive review of the field, recent developments intentionally were not addressed.
Predicting the stable rhodium based chalcopyrites with remarkable optical properties
Journal of Applied Physics, 2019
The ternary chalcopyrite compounds and related structures are well known for their noteworthy electronic and optical properties. The interaction between monovalent and trivalent atoms has a significant influence on their electronic as well as optical behavior. In the present work, a density functional theory based first-principles calculation is performed to investigate the structural, electronic, lattice dynamical, and optical properties of rhombohedral CuRhX 2 (X = S, Se, Te) compounds. The electronic band structure of these compounds depicts semiconducting nature with an indirect bandgap of 1.8, 1.17, and 0.75 eV for CuRhS 2 , CuRhSe 2 , and CuRhTe 2 , respectively. There is a greater hole mobility and p-type conductivity in these compounds due to strong p-d hybridization. The phonon dispersion curves of these compounds confirm their dynamical stability as there is no imaginary frequency for any of the phonon modes in the entire Brillouin zone (BZ). Furthermore, we discuss mode compatibility at the zone center of the BZ and other high symmetry points of the BZ. The Raman spectra of CuRhX 2 demonstrate two Raman active modes, namely, the E g and A 1g. The frequency of Raman active modes E g and A 1g decreases due to the increase in Rh-X bond length. The static dielectric constants fall in the range of 8.7-10.4. The absorption coefficient of these compounds is in the range of 1.5-2.0 eV depending upon the ionic radii of chalcogen atoms. Thus, it can be deduced that these systems can be efficiently used in solar energy converters in the UV as well as in the visible region.
Effect of Na substitution on electronic and optical properties of CuInS2 chalcopyrite semiconductor
Journal of Solid State Chemistry, 2015
We observe significant effects of structural distortion on electronic and optical properties of CdGa 2 X 4 (X = S, Se, Te) defect chalcopyrite. The calculation is carried out within Density functional theory based tight binding linear muffin tin orbital (TB-LMTO) method. Structural parameters and band gap of CdGa 2 X 4 agree well with the available experimental values within LDA limit. Change in band gap due to structural distortion is 3.63%, 4.0%, and 8.8% respectively. We observe significant change in optical properties also due to this effect. Effects on optical properties come mainly from optical matrix elements. Our results of these response functions agree well with the available experimental values.
Structure modifications in chalcopyrite semiconductors
2000
The microstructure of epitaxial CuInS 2 , CuGaSe 2 and polycrystalline CuInS 2 ®lms was studied by transmission electron microscopy. We found that the vapour-phase epitaxy of CuInS 2 below the transition temperature T c results in ®lms with chalcopyrite and CuAu-like structures. The formation of CuAu-like ordered phases within the ®lms is independent of the substrate orientation, whereas the amount of CuAu-like ordered Cu and In atoms can be in¯uenced by the substrate orientation. The co-existence of chalcopyrite and CuAu-like ordering of the metal atoms was also found in polycrystalline CuInS 2 ®lms prepared by sulphurization of Cu/In metal precursor at a temperature below T c . In contrast, vapour-phase epitaxy of CuGaSe 2 below T c provides only ®lms with the chalcopyrite structure. The experimental ®nding is in good agreement with the results of ®rst-principle band-structure calculations. q 2000 Elsevier Science S.A. All rights reserved.
Optik, 2018
Investigation of the physical properties of chalcopyrite materials using ab-initio methods have been carried out to simulate a new structure of thin-films photovoltaic cells with high conversion efficiency. The Density Functional Theory calculations have been performed using Wien2k computational package by employing the full-potential linearized augmented plane wave method. Structural and electronic properties of chalcopyrite semiconducting material Copper-Indium-Gallium-Selenium i.e. CuIn 1-x Ga x Se 2 have been investigated using local density approximation for the exchange-correlation potential. The electronic structures and linear optical properties have been studied using both the semi-local Becke-Johnson potential and its modified form i.e. mBJ and TB-mBJ. Computational results are in good agreement with those acquired experimentally. The viability of alloys in realization of ultra-thin-film based (CIGS) solar cells with high performance has been proposed after simulation and analysis study using one of solar cell simulation tools. The studied material exhibits capability to become a promising candidate for fabrication of optoelectronic and photovoltaic devices. x Ga x Se 2 solar cells. CIGS thin films have been elaborated using different techniques including, selenization of sequentially stacked precursors [8], physical evaporation [9] and rapid thermal process [10]. On the other hand, some theoretical performances are found
Physical Review, 1969
The first paper of this series showed that the portion of the total correlation energy, which remains after two types of correlation effects specific to X (number of electrons), symmetry state, and Z are taken out, is quite similar in nature to correlation in closed shells. This remainder, the "all-external energy" is expected to be by and large made up of pair correlations whose values are transferable through N, symmetry state, and Z as predicted in the theory by Sinanoglu. The present paper analyzes the all-external correlation energies of 8, C, N, 0, F, Ne, and Na into their irreducible all-external pair components. The predicted additivity and transferability of all-external pairs are found to hold within the error limits of experimental correlation energies. A set of such pair-correlation values applicable to a great many states and ions of 1s 2sm2p type are obtained. Together with the calculated values of the two other types of correlation effects, these yield nonrelativistic atomic energies to a root-mean-square deviation of 0.05 eV. A semiempirical method for the prediction of atomic energy levels of general nonclosed-shell species, excited configurations and states as well as ground states is presented. The method is applied to predictions of electron affinities, excited states of negative ions, excitation energies, intermultiplet separations, and term-splitting ratios. Results of the method are compared with experiment and other semiempirical and nonempirical methods.