Oxide route for production of Cu2ZnSnS4 solar cells by pulsed laser deposition

Gansukh, Mungunshagai; Mariño, Simón López; Rodriguez, Moises Espindola; Engberg, Sara Lena Josefin; Martinho, Filipe; Hajijafarassar, Alireza; Stamate, Eugen; Hansen, Ole; Schou, Jørgen; Canulescu, Stela

doi:10.1016/j.solmat.2020.110605

Cited by 19 publications

(13 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CZTS and ACZTS films were grown by pulsed laser deposition (PLD), using a similar procedure which led to an efficiency of solar cells produced by PLD of 5.4% 16 . The CZTS and ACZTS films were deposited at room temperature on Mo-coated soda-lime glass substrates placed at a distance of 5 cm from the target.…”

Section: Methodsmentioning

confidence: 99%

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Gansukh

Rodriguez

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

Energy band alignment at the heterointerface between CdS and kesterite Cu2ZnSnS4 (CZTS) and its alloys plays a crucial role in determining the efficiency of the solar cells. Whereas Ag alloying of CZTS has been shown to reduce anti-site defects in the bulk and thus rise the efficiency, the electronic properties at the interface with the CdS buffer layer have not been extensively investigated. In this work, we present a detailed study on the band alignment between n-CdS and p-CZTS upon Ag alloying by depth-profiling ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). Our findings indicate that core-level peaks and the valence band edge of CdS exhibit a significant shift to a lower energy (larger than 0.4 eV) upon the etching of the CdS layer, which can be assigned due to band bending and chemical shift induced by a change in the chemical composition across the interface. Using a simplified model based on charge depletion layer conservation, a significantly larger total charge region depletion width was determined in Ag-alloyed CZTS as compared to its undoped counterpart. Our findings reveal a cliff-like band alignment at both CdS/CZTS and CdS/Ag-CZTS heterointerfaces. However, the conduction-band offset decreases by more than 0.1 eV upon Ag alloying of CZTS. The approach demonstrated here enables nanometer-scale depth profiling of the electronic structure of the p–n junction and can be universally applied to study entirely new platforms of oxide/chalcogenide heterostructures for next-generation optoelectronic devices.

show abstract

Section: Methodsmentioning

confidence: 99%

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Gansukh

Rodriguez

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…We can provide an additional example from another work by our group. We have also produced CZTS devices based on PLD of single targets, using oxide-based targets and sulfide-based targets . For sulfide-based targets, the precursors consist of a mix of sulfide binaries generally with a high S/metals ratio (close to 1, in particular for low laser fluences), and indeed, we do not see any evidence of double-layer formation, even in absorbers with thicknesses above 2 μm, processed in the same 1S annealing conditions described in this work.…”

Section: Resultsmentioning

confidence: 57%

“…A fifth case, shown in Figure e, can be found in alternative kesterite synthesis routes based on oxide precursors. The example of Figure e corresponds to a CZTS device based on pulsed laser deposition from an oxide target, which we have discussed in previous work …”

Section: Survey Of the Occurrence Of Double-layered Kesterites In The...mentioning

confidence: 99%

“…The example of Figure 1e corresponds to a CZTS device based on pulsed laser deposition from an oxide target, which we have discussed in previous work. 42 In this work, we will discuss mostly the cases of Figure 1a−c. There are a number of instances of this kind of double layer appearing in the literature, and important direct or indirect insights on its dynamics appear across multiple publications.…”

Section: Survey Of the Occurrence Of Double-layered Kesterites In The...mentioning

confidence: 99%

See 1 more Smart Citation

Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review

Martinho

López-Mariño

Espíndola‐Rodríguez

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

In kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cell research, an asymmetric crystallization profile is often obtained after annealing, resulting in a bilayered -or double-layered -CZTSSe absorber. So far, only segregated pieces of research exist to characterize the appearance of this double layer, its formation dynamics and its effect on the performance of devices. In this work, we review the existing research on double-layered kesterites and evaluate the different mechanisms proposed. Using a cosputtering-based approach, we show that the two layers can differ significantly in morphology, composition and optoelectronic properties, and complement the results with a large statistical dataset of over 850 individual CZTS solar cells. By reducing the absorber thickness from above 1000 nm to 300 nm, we show that the double layer segregation is alleviated. In turn, we see a progressive improvement in the device performance for lower thickness, which alone would be inconsistent with the well-known case of ultrathin CIGS solar cells. We therefore attribute the improvements to the reduced double-layer occurrence, and find that the double layer limits the efficiency of our devices to below 7%. By comparing the results with CZTS grown on monocrystalline Si substrates, without a native Na supply, we show that the alkali metal supply does not determine the double layer formation, but merely reduces the threshold for its occurrence. Instead, we propose that the main formation mechanism is the early migration of Cu to the surface during annealing and formation of Cu2-xS phases, in a self-regulating process akin to the Kirkendall effect. Finally, we comment on the generality of the mechanism proposed, by comparing our results to other synthesis routes, including our own in-house results from solution processing and pulsed laser deposition of sulfide-and oxide-based targets. We find that although the double layer occurrence largely depends on the kesterite synthesis route, the common factors determining the double layer occurrence appear to be the presence of metallic Cu and/or a chalcogen deficiency in the precursor matrix. We suggest that understanding the limitations imposed by the double layer dynamics could prove useful to pave the way for breaking the 13% efficiency barrier for this technology.

show abstract

“…Currently, the commonly used vacuum methods include sputtering, [7][8][9][10] evaporation, [11][12][13][14] and pulsed laser deposition. [15][16][17] For example, Yan et al obtained 11.01% efficient Cu 2 ZnSnS 4 solar cells via cosputtering Cu/ZnS/SnS materials with the heterojunction heat treatment. [18] Li et al achieved Cu 2 ZnSnSe 4 solar cells with 11.95% efficiency fabricated by sputtering a Cu-Zn-Sn-Se quaternary compound target.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the Ratio of Sn⁴⁺ and Sn²⁺ in Cu₂ZnSn(S,Se)₄ Precursor Solution via Air Environment for Highly Efficient Solar Cells

Liang

Xie

et al. 2021

Solar RRL

View full text Add to dashboard Cite

The use of different Sn valence states (such as Sn4+ and Sn2+) in the Cu2ZnSn(S,Se)4 (CZTSSe) precursor solution is especially important for the quality of the subsequent growth of the CZTSSe films. The latest study has found that replacing SnCl2·2H2O with anhydrous SnCl4 can remarkably improve the performance of CZTSSe solar cells, but it needs to be operated in the glovebox. Herein, for the precursor solution, SnCl4·5H2O powder is used instead of anhydrous SnCl4 in air environment, and the proportion of Sn4+ and Sn2+ precursor solutions is further systematically studied. When the ratio of Sn4+ to Sn2+ is 1:1, a uniform, compact, and noncracking CZTSSe thin film is obtained, effectively alleviating the interface recombination and reducing the concentration of deep‐level defects. In particular, the concentration of CuZn antisite defects is decreased by an order of magnitude, and the carrier recombination and band tail effect are alleviated. When JSC is maintained, VOC and FF are considerably improved. Finally, CZTSSe thin‐film solar cells are fabricated with an efficiency of over 11%. Herein, the feasibility of controlling the ratio of Sn4+ to Sn2+ in the CZTSSe precursor solution for higher efficiency of CZTSSe thin‐film solar cells is demonstrated.

show abstract

Oxide route for production of Cu2ZnSnS4 solar cells by pulsed laser deposition

Cited by 19 publications

References 46 publications

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review

Optimizing the Ratio of Sn⁴⁺ and Sn²⁺ in Cu₂ZnSn(S,Se)₄ Precursor Solution via Air Environment for Highly Efficient Solar Cells

Contact Info

Product

Resources

About

Oxide route for production of Cu2ZnSnS4 solar cells by pulsed laser deposition

Cited by 19 publications

References 46 publications

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review

Optimizing the Ratio of Sn4+ and Sn2+ in Cu2ZnSn(S,Se)4 Precursor Solution via Air Environment for Highly Efficient Solar Cells

Contact Info

Product

Resources

About

Optimizing the Ratio of Sn⁴⁺ and Sn²⁺ in Cu₂ZnSn(S,Se)₄ Precursor Solution via Air Environment for Highly Efficient Solar Cells