Anomalous persistent photoconductivity in Cu2ZnSnS4 thin films and solar cells

Abelenda, A.; Sánchez, María Cristina Polo; Ribeiro, G. M.; Fernandes, Paulo A.; Salomé, Pedro M. P.; Cunha, A. F. da; Leitão, J. P.; Silva, M.I.N. da; González, J. C.

doi:10.1016/j.solmat.2015.02.001

Cited by 21 publications

(10 citation statements)

References 43 publications

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“…When projecting CZTS bandgap fluctuation into 1D layer or uniform 2D bulk for simulation, we can use a reduced effective bandgap (E g,eff ) for flat band approximation [46]. Therefore bandgapfluctuation induced tailing states in disordered CZTS may translate into enhanced carrier concentration and hence larger saturation current in device model where idealized semiconductor is assumed.…”

Section: Disorder In Bulkmentioning

confidence: 99%

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Yan

et al. 2017

Solar Energy Materials and Solar Cells

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In this work we perform comprehensive characterization on a 6.9% pure sulphide Cu 2 ZnSnS 4 (CZTS) device and construct a 2D device model in Sentaurus TCAD to identify possible roots of performance bottlenecks. Electrical and optical parameters of the absorber from comprehensive electrical and optical characterization, together with other necessary parameters from literature, we successfully reproduce measured current density-voltage (J-V) and external quantum efficiency (EQE) curves. Absorption coefficient is extracted by fitting measured internal quantum efficiency (IQE). At the buffer/absorber interface, a surface recombination velocity of 1×10 5 cm/s is identified to adequately describe measured spectral response at the near-interface region. Furthermore, a bulk lifetime of ~29 ns is extracted from effective lifetime modelling in conjunction with time resolved photoluminescence (TRPL) results. The key underlying V oc deficit, ~200 mV, is pinpointed to bandgap fluctuation, which is backed by the simulation study on both QE tail and steady state photoluminescence.

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Section: Disorder In Bulkmentioning

confidence: 99%

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Yan

et al. 2017

Solar Energy Materials and Solar Cells

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“…The CZTSSe compound is characterized by a strong self‐doping and high compensation . The interaction between defects, with relevance for the donors, create electrostatic fluctuating potentials along the film (), which determines critically the electronic energy levels structure and the dynamics of the charge carriers in the material . One of the important issues in the physical characterization of an optoelectronic material is the influence of structural properties and growth conditions on the electronic energy levels structure and charge carriers dynamics.…”

Section: Introductionmentioning

confidence: 99%

Optical and structural investigation of Cu₂ZnSnS₄ based solar cells

Teixeira

Salomé

Sousa

et al. 2016

Physica Status Solidi (b)

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The structural and optical properties of two solar cells in which the Cu2ZnSnS4 absorber layer was sulphurized by two different methods (S flux and graphite box), were studied. The grain sizes are dependent on the sulphurization method, the larger ones being obtained for the sulphurization in a S flux. The optical properties were investigated by photoluminescence (PL). A broad and asymmetric band was observed for the sample with the larger grains, whereas for the other one a very broad emission was obtained, mostly influenced by the CdS buffer layer. The dependence on the excitation power revealed the influence of fluctuating potentials created by strong doping and high compensation of the absorber layer. Radiative recombination channels are quite different from the ones typical of semiconductor materials with flat bands. A relationship between the PL intensity from the absorber layer measured at low temperatures, and the final PV performance is established. Thus, we propose that PL can be used as an evaluation experimental technique in order to decide if a certain absorber should be processed into a full solar cell or not.

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“…The development of nontoxic new absorber materials, with earth-abundant constituents, represents a promising alternative solution. Substitution of the chalcopyrite CIGS by the kesterite absorber Cu 2 ZnSn(S,Se) 4 (CZTS), [9] where abundant Zn and Sn are used instead of In and Ga, while keeping similar optoelectronic properties [10] and the same CIGSbased solar cell structure, [11] is one of the alternatives. However, the conversion efficiency of CZTS-based solar cells has been stagnant at 12.6% since 2014.…”

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confidence: 99%

Deciphering the Role of Defects in the Ambipolar Electrical Transport in Nanocrystalline Sb₂Se₃ Thin Films

González

Limborço

Ribeiro‐Andrade

et al. 2021

Adv Elect Materials

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The role of two defects in the ambipolar character of nanocrystalline selenium poor Sb2Se3 is studied. At low temperature, the electrical transport in Sb2Se3 thin films with nm‐sized crystallites and grains is dominated by the ionization of a shallow acceptor, while at high temperature a deep donor is the leading one. The ionization energy of the deep donor agrees with theoretical reports for selenium vacancies. However, the value of the ionization energy of the shallow acceptor is in contradiction with theoretical reports pointing out to an unreported shallow defect. These findings have been confirmed by two independent experimental techniques, Electron Paramagnetic Resonance, and electrical transport as a function of temperature. The mobility of the free carriers has been found not to be limited by grain potential barriers (GPB), in contrast with polycrystalline thin films. Both findings, new shallow acceptor and zero height GPB, constitute advantages for the design of nanostructured Sb2Se3‐based solar cells and other optoelectronic devices. These results not only provide useful information for the growth of nanocrystalline Sb2Se3 thin films with ambipolar transport properties, but also about the complexity of defect physics in low‐symmetry and Q1D semiconductors.

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Anomalous persistent photoconductivity in Cu2ZnSnS4 thin films and solar cells

Cited by 21 publications

References 43 publications

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Optical and structural investigation of Cu₂ZnSnS₄ based solar cells

Deciphering the Role of Defects in the Ambipolar Electrical Transport in Nanocrystalline Sb₂Se₃ Thin Films

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Anomalous persistent photoconductivity in Cu2ZnSnS4 thin films and solar cells

Cited by 21 publications

References 43 publications

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Sentaurus modelling of 6.9% Cu2ZnSnS4 device based on comprehensive electrical & optical characterization

Optical and structural investigation of Cu2ZnSnS4 based solar cells

Deciphering the Role of Defects in the Ambipolar Electrical Transport in Nanocrystalline Sb2Se3 Thin Films

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Product

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Optical and structural investigation of Cu₂ZnSnS₄ based solar cells

Deciphering the Role of Defects in the Ambipolar Electrical Transport in Nanocrystalline Sb₂Se₃ Thin Films