First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides (original) (raw)
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Investigation of chalcogenide absorber materials for photovoltaic applications
2012
The synthesis of morphologically good thin chalcogenide films via the two-stage route is a chemical challenge. The reactivity towards the chalcogen-bearing reactants of the different metals within the precursor film is a trade-off between thermodynamic driving force and kinetics of binary sulfide formation. In this work, CuSbS2 and Cu3BiS3 thin films were produced by conversion of stacked and co-electroplated metal precursor layers in the presence of elemental sulfur vapour. Ex-situ XRD and SEM/EDS analyses of RTP treated samples were employed to study the reaction sequence and create ‘‘Time-Temperature-Reaction’’ diagrams for the description of the reaction kinetics. Modified Pilling–Bedworth coefficients were introduced for the interpretation of the experimental results. The chalcogenizing conditions have a strong influence on the following aspects: (1) Extent of intermediate phase segregation and/or crystallite size (2) Thermodynamic (de)stabilization at low temperature (3) Therm...
Physica status solidi, 2017
We investigated the use of ternary and quaternary chalcogenide compounds based on Cu, Zn, Sn and Si for use as high band gap absorber layers in thin film photovoltaics. We have investigated the fabrication of Cu2Zn(Sn,Si)Se4, Cu2Si(S,Se)3 and Cu8Si(S,Se)6 thin film layers. Whereas Cu2Zn(Sn,Si)Se4 and Cu2Si(S,Se)3 appeared to be difficult to fabricate, because the Si did not intermix well with the rest of the elements at the typical process temperatures used for glass substrates, Cu2ZnSiSe4 and Cu8Si(S,Se)6 could be formed. The fabricated layers were polycrystalline with a typical thickness of about 1 µm. We also fabricated solar cells with the different absorber materials, using a standard Mo back contact and CdS/ZnO buffer layer combination, but despite very bright photoluminescence response of the Cu8SiS6 and Cu8SiSe6 layers at an energy of about 1.84 eV and 1.3 eV respectively, the measured efficiencies remained below 0.1 % due to particularly low photocurrents.
Solution-processed Cu(In,Ga)(S,Se) 2 absorber yielding a 15.2% efficient solar cell
Progress in Photovoltaics: Research and Applications, 2012
The remarkable potential for inexpensive upscale of solution processing technologies is expected to enable chalcogenidebased photovoltaic systems to become more widely adopted to meet worldwide energy needs. Here, we report a thin-film solar cell with solution-processed Cu(In,Ga)(S,Se) 2 (CIGS) absorber. The power conversion efficiency of 15.2% is the highest published value for a pure solution deposition technique for any photovoltaic absorber material and is on par with the best nonvacuum-processed CIGS devices. We compare the performance of our cell with a world champion vacuum-deposited CIGS cell and perform detailed characterization, such as biased quantum efficiency, temperature-dependent electrical measurement, time-resolved photoluminescence, and capacitance spectroscopy.
Zeitschrift für anorganische und allgemeine Chemie, 2012
Light harvesting chalcogenide materials have strong potential applications for photovoltaic due, in part, to the ability of their structures to accommodate shift from the ideal stoichiometry. This study is devoted to the chemical and structural investigations of two specific series of materials, Cu(In,Ga)Se 2 (CIGSe) and Cu 2 ZnSnS 4 (CZTS). Both of them receive currently a strong incentive in the domain of thin film solar cells. On the basis of accurate chemical analy
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Przegląd Elektrotechniczny (Electrical Review), 2015
A method for calculation of the Cu(In,Ga)(S,Se)2-layer parameters (space-charge region width, diffusion length, built-in potential and concentration of non-compensated acceptors) in solar cell is proposed. The method is based on analysis of the quantum efficiency spectra within the framework of a solar-cell unidimensional model.
2015
DFT analyses of band structure dispersion and of contribution of different anionic sub-groups to the studied electronic structure together with the anisotropy of optical functions were performed for the two promising solar cell crystals Cu2ZnSnS4 and Cu2ZnSnSe4. We have applied the state-of-the-art full potential linear augmented plane wave (FPLAPW) method in a scalar relativistic version. Exchange and correlation potential were introduced within a framework of the local density approximation (LDA) and gradient approximation (GGA). We show that Cu2ZnSnS4 as well as Cu2ZnSnSe4 crystals possess a direct energy band gap situated around the center of the BZ. Careful analysis of the total density of states together with the partial contribution of the particular orbital were performed for evaluations of contribution of corresponding bonds to the origin of the chemical bonds. Role of replacing of S by Se is analyzed in the details for the electronic density of states with respect to
Journal of Applied Physics, 2020
Chalcopyrites are a demonstrated material platform for realizing efficient thin-film photovoltaics, with the most well known Cu(In,Ga)Se2 (CIGS)-based solar cells exceeding 23%. Several factors, including flexibility in tuning the absorber bandgap, enhanced surface treatments, and the electrically benign nature of common defects are responsible for the existing high performance and future promise in chalcopyrite-based photovoltaic devices. The introduction of Cu-poor phases (also known as ordered-vacancy compounds or OVCs) between the absorber and buffer layers in CIGS solar cells is known to enhance device performance; however, the overall properties and role of OVCs remain poorly understood. Using first principles calculations based on the density functional theory with screened hybrid functionals, we explore the electronic structure and stability of OVCs and their band offsets with defect-free chalcopyrite layers in Cu- and Ag-based compounds (ABX2 where A=Cu, Ag; B=In, Ga, Al; a...
DFT analyses of band structure dispersion and of contribution of different anionic sub-groups to the studied electronic structure together with the anisotropy of optical functions were performed for the two promising solar cell crystals Cu 2 ZnSnS 4 and Cu 2 ZnSnSe 4 . We have applied the state-of-the-art full potential linear augmented plane wave (FPLAPW) method in a scalar relativistic version. Exchange and correlation potential were introduced within a framework of the local density approximation (LDA) and gradient approximation (GGA). We show that Cu 2 ZnSnS 4 as well as Cu 2 ZnSnSe 4 crystals possess a direct energy band gap situated around the center of the BZ. Careful analysis of the total density of states together with the partial contribution of the particular orbital were performed for evaluations of contribution of corresponding bonds to the origin of the chemical bonds. Role of replacing of S by Se is analyzed in the details for the electronic density of states with respect to the nature of chemical bonds. The principal analysis is performed for the dispersion of the optical constants. The influence of the different chemical bonds into the dispersion of the optical functions is analyzed in order to optimize the optical features with respect to the requirements of the solar cell elements.