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- Abou-Ras, Daniel, et al.
(författare)
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Innovation highway : Breakthrough milestones and key developments in chalcopyrite photovoltaics from a retrospective viewpoint
- 2017
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 633, s. 2-12
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Scragg, Jonathan, 1983-, et al.
(författare)
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Cu–Zn disorder and band gap fluctuations in Cu2ZnSn(S,Se)4 : Theoretical and experimental investigations
- 2016
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 253:2, s. 247-254
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Tidskriftsartikel (refereegranskat)abstract
- Cu2ZnSn(S,Se)4 (CZTS(e)) solar cells suffer from low-open-circuit voltages that have been blamed on the existence of band gap fluctuations, with different possible origins. In this paper, we show from both theoretical and experimental standpoints that disorder of Cu and Zn atoms is in all probability the primary cause of these fluctuations. First, quantification of Cu–Zn disorder in CZTS thin films is presented. The results indicate that disorder is prevalent in the majority of practical samples used for solar cells. Then, ab initio calculations for different arrangements and densities of disorder-induced [CuZn + ZnCu] defect pairs are presented and it is shown that spatial variations in band gap of the order of 200 meV can easily be caused by Cu–Zn disorder, which would cause large voltage losses in solar cells. Experiments using Raman spectroscopy and room temperature photoluminescence combined with in situ heat-treatments show that a shift in the energy of the dominant band-to-band recombination pathway correlates perfectly to the order-disorder transition, which clearly implicates Cu–Zn disorder as the cause of band gap fluctuations in CZTS. Our results suggest that elimination or passivation of Cu–Zn disorder could be very important for future improvements in the efficiency of CZTS(e)-based solar cells.
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| 3. |
- Sendler, Jan, et al.
(författare)
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Photoluminescence studies in epitaxial CZTSe thin films
- 2016
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 120:12
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial Cu2ZnSnSe4 (CZTSe) thin films were grown by molecular beam epitaxy on GaAs(001) using two different growth processes, one containing an in-situ annealing stage as used for solar cell absorbers and one for which this step was omitted. Photoluminescences (PL) measurements carried out on these samples show no dependence of the emission shape on the excitation intensity at different temperatures ranging from 4K to 300 K. To describe the PL measurements, we employ a model with fluctuating band edges in which the density of states of the resulting tail states does not seem to depend on the excited charge carrier density. In this interpretation, the PL measurements show that the annealing stage removes a defect level, which is present in the samples without this annealing.
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