Heterojunction interface passivation strategy for Cu(In1-x,Gax)Se2 solar cell with nano-level engineering of Zn-based buffer structure via atomic layer deposition method

Shin, Sang Su; Kim, Kihwan; Yoo, Jinsu; Kim, Ji Hye; Ahn, Sungsook; Cho, Ara; Kim, Dongryeol; Jo, Yonghee; Jeong, Inyoung; Shin, Donghyeop; Yun, Jae Ho; Park, Jonghoo; Park, Joo Hyung

doi:10.1016/j.solmat.2021.111010

Cited by 10 publications

(9 citation statements)

References 60 publications

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“…The resulting JV data for these solar cells (Tables and ; Figures , S10, and S11) show that V oc improved to values comparable to using ZGO 0.32 ESL. Such an effect is in line with previous studies where thin ZnS interlayers at the ESL/CIGS interface improved V oc by lowering the recombination. , While not completely understood, some studies have suggested that Zn reacts with the surface and occupies Cu vacancies that are prevalent on these absorbers. This effectively dopes the surface n-type and has been suggested to push the p–n junction into the absorber and thus lower the influence of interface recombination. − To test if this V oc gain was exclusive to using a DEZ + H 2 S exposure of the ACIGS surface, a similar exposure test was performed with a single Al 2 O 3 ALD cycle (Al(CH 3 ) 3 (trimethylaluminum, TMA) and H 2 O).…”

Section: Resultssupporting

confidence: 90%

“…Such an effect is in line with previous studies where thin ZnS interlayers at the ESL/CIGS interface improved V oc by lowering the recombination. 9,52 While not completely understood, some studies have suggested that Zn reacts with the surface and occupies Cu vacancies that are prevalent on these absorbers. This effectively dopes the surface n-type and has been suggested to push the p−n junction into the absorber and thus lower the influence of interface recombination.…”

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confidence: 99%

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Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Hultqvist,

Keller,

Martin

et al. 2023

ACS Appl. Energy Mater.

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Two inorganic electron-selective layers (ESLs), Sn 1−x Ge x O y (TGO) and Zn 1−x Ge x O y (ZGO), were developed by using atomic layer deposition (ALD) with in situ quartz crystal monitoring. To ensure (Ag,Cu)(In,Ga)Se 2 (ACIGS) solar cell compatibility, a 120 °C ALD process was developed for GeO y using Ge(N(CH 3 ) 2 ) 4 and H 2 O as precursors. In the ALD supercycle approach, the GeO y ALD cycle was interchanged with either ZnO or SnO y cycles to deposit TGO and ZGO with varying conduction band positions (E c ), respectively. The material properties were experimentally verified using X-ray photoelectron spectroscopy and optical absorption and by employing these films as ESLs in ACIGS solar cells. There, the open-circuit voltage initially increased as the Ge content of the TGO and ZGO films increased due to the ESL E c simultaneously shifting up from the low position in ZnO or SnO y to match the ACIGS E c . As the Ge content increased further, the fill factor (FF) of these devices decreased since the ESL E c became positioned significantly above the ACIGS E c , forming an energy barrier as seen from ACIGS. As a result, the efficiency of the ACIGS solar cell peaked for an intermediate Ge content for both TGO and ZGO. Using good TGO and ZGO compositions in ACIGS solar cells gave efficiencies of up to 14.8 and 17.0%, respectively, which were lower than the reference best cell efficiencies of up to 19.5% for CdS and 18.2% for Zn 1−x Sn x O y (ZTO). ZGO was, however, able to shift its E c further up than ZTO, making it a potent ESL for high-band-gap absorbers. Based on the results, we listed a few key properties that are required for a good ACIGS solar cell ESL and gave a few suggestions on how they are linked to the previous success of ZTO.

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Section: Resultssupporting

confidence: 90%

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confidence: 99%

Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Hultqvist,

Keller,

Martin

et al. 2023

ACS Appl. Energy Mater.

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“…It was deduced that the hydroxide in the Zn(O,S) layer causes tunneling recombination at the interface which is reduced using ALD‐deposited ZnS. [ 70 ]…”

Section: Cigse Solar Cellsmentioning

confidence: 99%

Dielectric Front Passivation for Cu(In,Ga)Se₂Solar Cells: Status and Prospect

Wild

Scaffidi

Brammertz

et al. 2022

Adv Energy and Sustain Res

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Cu(In,Ga)Se2 (CIGSe) solar cells are among the most efficient thin‐film solar cells on lab scale. However, this thin‐film technology has relatively large upscaling losses for commercial technology. To tackle this, paradigm shifts are proposed that allow for simpler, cost‐effective, and efficient CIGSe solar cells. Front passivation using dielectric layers is one of the options being investigated as this is widely used in Si technology. Research on front passivation for CIGSe is in an early stage and no improvements are made yet. A close comparison with silicon technology is made to understand why it seems to be more difficult for CIGSe solar cells. In general, chemical passivation is less effective, resulting in higher interface defect densities than seen for Si. Also, field‐effect passivation requires positive charges, which have not been implemented yet on the CIGSe front surface. Finally, for Si passivation, often a high‐temperature annealing step is applied, which is not possible for CIGSe. It is proposed to apply a dielectric tunneling layer with positive fixed charges in combination with an electron transport layer to move forward. A list of potential dielectric layers that could be suitable for CIGSe is provided.

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“…The CdS possesses a low bandgap of 2.4 eV, which is not sufficient to cover the maximum shorter wavelength of photons, resulting in absorption losses. For high efficiency, it is necessary to replace the CdS buffer layer (BL), which still contains the toxic Cd, with better suited BL to form a good heterojunction [33][34][35][36]. Introducing ZnS as a better n-type BL due to its high-bandgap semiconducting and better lattice match with CIGS [34][35][36][37][38][39][40], it has been found that using dielectric passivation layers at the front could increase light absorption and be sufficient to establish long-term stability [34,35].…”

Section: Introductionmentioning

confidence: 99%

Graded Bandgap Ultrathin CIGS Solar Cells

et al. 2023

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In this paper, we physically modeled passivated ultrathin Cu (In1−xGax) Se2 solar cells with different bandgap grading configurations. Firstly, we have designed the cell architecture according to the fabricated model. The novelty in this work is the modeling of passivated u-CIGS solar cells with different bandgap grading profile configurations in order to achieve high efficiency with a thickness of 500 nm. A significant influence on device performance has been observed while changing absorber doping density, electron affinity, and operating temperature (range of 10–70 °C) for the investigated samples. ZnS has been used as a buffer layer to replace the conventional CdS material in order to improve cell efficiency. The impact of the buffer doping density and electron affinity on u-CIGS cell performance is explored. The simulation results show that a high bandgap at the front and rear sides with an acceptor density of 2 × 1016 provide the best electrical cell parameters: Jsc of 31.53 mA/cm2, Voc of 742.78 mV, FF of 77.50%, η of 18.15%. Our findings can be considered guidelines for new single and/or tandem cell optimization to achieve high efficiency.

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Heterojunction interface passivation strategy for Cu(In1-x,Gax)Se2 solar cell with nano-level engineering of Zn-based buffer structure via atomic layer deposition method

Cited by 10 publications

References 60 publications

Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Dielectric Front Passivation for Cu(In,Ga)Se₂Solar Cells: Status and Prospect

Graded Bandgap Ultrathin CIGS Solar Cells

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Heterojunction interface passivation strategy for Cu(In1-x,Gax)Se2 solar cell with nano-level engineering of Zn-based buffer structure via atomic layer deposition method

Cited by 10 publications

References 60 publications

Sn1–xGexOy and Zn1–xGexOy by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se2 Solar Cells

Sn1–xGexOy and Zn1–xGexOy by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se2 Solar Cells

Dielectric Front Passivation for Cu(In,Ga)Se2Solar Cells: Status and Prospect

Graded Bandgap Ultrathin CIGS Solar Cells

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Product

Resources

About

Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Sn_1–xGe_xO_y and Zn_1–xGe_xO_y by Atomic Layer Deposition─Growth Dynamics, Film Properties, and Compositional Tuning for Charge Selective Transport in (Ag,Cu)(In,Ga)Se₂ Solar Cells

Dielectric Front Passivation for Cu(In,Ga)Se₂Solar Cells: Status and Prospect