New insights into the Mo/Cu(In,Ga)Se2 interface in thin film solar cells: Formation and properties of the MoSe2 interfacial layer

Klinkert, Torben; Theys, B.; Patriarche, G.; Jubault, Marie; Donsanti, Frédérique; Guillemoles, Jean‐François; Lincot, Daniel

doi:10.1063/1.4964677

Cited by 33 publications

(16 citation statements)

References 24 publications

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“…For instance, in the preparation of CIGSSe solar cells, selenization of CIGS on Mo substrate is usually conducted at 450–540 °C for tens of minutes. This selenization process can lead to the generation of CIGSSe, together with selenization of Mo substrate surface to MoSe 2 , indicating the excellent permeation capability of selenium across the entire metal sulfide film at high temperature . Therefore, this method is difficult to generate gradient composition.…”

Section: Methodsmentioning

confidence: 99%

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Zhang

Jiang

et al. 2017

Solar RRL

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To efficiently convert solar energy into electricity at low cost with long‐term stability is one of the major tasks in solar cell research and applications. Antimony sulfide‐selenide [Sb2(S1−xSex)3] with a tunable bandgap in the range of 1.1–1.8 eV are considered promising photovoltaic materials due to their low‐toxicity, long‐term durability, and abundant element availability. Herein, selenium‐graded Sb2(S1−xSex)3 is synthesized through diffusion controlled solid‐state reaction between selenium and pre‐formed Sb2S3 film. In the device, sulfur‐rich Sb2(S1−xSex)3 with large bandgap leads to high voltage output, while narrow‐bandgap selenium‐rich Sb2(S1−xSex)3 expands spectral response toward longer wavelength. As a consequence, the device yields an open‐circuit voltage comparable to Sb2S3 solar cell, along with a significantly enhanced photocurrent density of 19.43 mA cm−2, finally delivering a certified power conversion efficiency of 5.71%, which is the highest certified value in planar heterojunction solar cells based on Sb2(S1−xSex)3. Initial stability examination shows that the device can maintain 88% efficiency after storing for 90 days in moderate humidity and ambient light irradiation. This investigation offers an effective strategy to the fabrication of composition‐graded Sb2(S1−xSex)3 for long‐term stable devices. The methodology may be extended for the fabrication of a broad class of composition‐graded metal sulfide/selenide for solar cell performance enhancement.

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Section: Methodsmentioning

confidence: 99%

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Zhang

Jiang

et al. 2017

Solar RRL

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“…Interestingly, this barrier is lowered in the presence of Na [75]. The effect of MoSe 2 orientation on the Mo/MoSe 2 /absorber junction has been experimentally studied in the case of CIGSe technology [76,77]. It was found that while the back contact/ absorber contact resistance is twice as low for the MoSe 2 c-axis parallel orientation, the influence of Na plays a more important role on the contact resistance than the MoSe 2 orientation.…”

Section: Electrical Properties Of the Back Contactmentioning

confidence: 99%

Back and front contacts in kesterite solar cells: state-of-the-art and open questions

et al. 2019

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We review the present state-of-the-art within back and front contacts in kesterite thin film solar cells, as well as the current challenges. At the back contact, molybdenum (Mo) is generally used, and thick Mo(S, Se) 2 films of up to several hundred nanometers are seen in record devices, in particular for selenium-rich kesterite. The electrical properties of Mo(S, Se) 2 can vary strongly depending on orientation and indiffusion of elements from the device stack, and there are indications that the back contact properties are less ideal in the sulfide as compared to the selenide case. However, the electronic interface structure of this contact is generally not well-studied and thus poorly understood, and more measurements are needed for a conclusive statement. Transparent back contacts is a relatively new topic attracting attention as crucial component in bifacial and multijunction solar cells. Front illuminated efficiencies of up to 6% have so far been achieved by adding interlayers that are not always fully transparent. For the front contact, a favorable energy level alignment at the kesterite/CdS interface can be confirmed for kesterite absorbers with an intermediate [S]/([S]+[Se]) composition. This agrees with the fact that kesterite absorbers of this composition reach highest efficiencies when CdS buffer layers are employed, while alternative buffer materials with larger band gap, such as Cd 1−x Zn x S or Zn 1−x Sn x O y , result in higher efficiencies than devices with CdS buffers when sulfurrich kesterite absorbers are used. Etching of the kesterite absorber surface, and annealing in air or inert atmosphere before or after buffer layer deposition, has shown strong impact on device performance. Heterojunction annealing to promote interdiffusion was used for the highest performing sulfide kesterite device and air-annealing was reported important for selenium-rich record solar cells. Cu 2 ZnSnS 4 (CZTS) absorbers for solar cell applications was first reported by Ito and Nakazawa [1]. Early results on CZTS device performance were reported by Friedlmeier et al [2], Seol et al [3], and Katagiri et al [4]. Later a group at IBM reached record performances with power conversion efficiencies (PCEs) above 10% for CZTSSe devices in 2010 [5] and the current record PCE of 12.6% in 2013 [6]. In 2018, researchers from DGIST reached the same performance, 12.6%, but for a larger device area [7]. The device structure used for kesterite solar cells was originally copied from that of Cu(In, Ga)Se 2 , (CIGSe) TFSCs, and is formed by sequential deposition, upon a soda lime glass substrate, of a Mo back contact, the absorber, a CdS buffer layer, and a ZnO/ZnO:Al bi-layer window (i.e. transparent top contact). This structure, schematically shown for CZTSSe in figure 1, is not necessarily ideal for kesterite solar cells, and extensive work has been invested into studies of alternative backand front contacts and related deposition processes. In this paper, the state-of-the-art and current open questions related to the back and front c...

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“…Considering the experience accumulated for other chalcogenides such as CIGSSe, the adhesion onto glass/Mo substrates is expected to be good, if one can control the formation of Mo(S,Se) 2 and the synthesis parameters. In fact, the uncontrolled sulfurization/selenization of Mo can have a strong impact on the adhesion properties of the absorber on the substrate [100].…”

Section: Morphological Propertiesmentioning

confidence: 99%

Physical routes for the synthesis of kesterite

et al. 2019

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This paper provides an overview of the physical vapor technologies used to synthesize Cu 2 ZnSn(S,Se) 4 thin films as absorber layers for photovoltaic applications. Through the years, CZT(S,Se) thin films have been fabricated using sequential stacking or co-sputtering of precursors as well as using sequential or co-evaporation of elemental sources, leading to high-efficient solar cells. In addition, pulsed laser deposition of composite targets and monograin growth by the molten salt method were developed as alternative methods for kesterite layers deposition. This review presents the growing increase of the kesterite-based solar cell efficiencies achieved over the recent years. A historical description of the main issues limiting this efficiency and of the experimental pathways designed to prevent or limit these issues is provided and discussed as well. A final section is dedicated to the description of promising process steps aiming at further improvements of solar cell efficiency, such as alkali doping and bandgap grading. intensive research on Cu 2 ZnSn(S,Se) 4 (CZT(S,Se)) kesterite compounds as CRM-free absorber layers for PV applications is essential. This article aims at establishing a complete overview of the physical routes used for the synthesis of kesterite thin films as absorber layers in solar cells. The following sections are devoted to that objective and will take on the main issues which have been raised so far as well as how the processes have evolved through the years to meet the requirements of the market. Some major advancements in terms of deposition or post-deposition treatments are introduced. Advantages and drawbacks of each of the physical methods presented in this review are described in detail and compared to other physical or chemical synthesis routes. Physical routes: status overviewWe performed an extensive identification of the common processes and methods used for the synthesis of kesterite thin films or for the design of solar cell devices. In order to avoid unnecessary repetitions along this paper, this section first explains these well-known and commonly used experimental processes and methods. Historically, based on the similarities between kesterite and chalcopyrite compounds, the standard device structure adopted for Cu(In,Ga)(S,Se) 2 (CIGSSe) was directly extended to CZTSSe, by simply replacing the CIGSSe absorber layer with a p-type CZTSSe thin film. CZTSSe solar cells are then typically produced using a soda-lime glass (SLG) substrate coated with a sputtered Mo layer acting as rear metallic contact. Typical sputter-deposited Mo layer thickness is around 500 nm up to 1 μm [12]. The kesterite absorber is then deposited onto the Mo layer.The fabrication of this absorber consists in the deposition of a precursor layer via a physical or a chemical route, which is then annealed in a reactive atmosphere containing either S (sulfurization) or Se (selenization). As a common result of the reactive annealing, a thin Mo(S,Se) 2 layer is naturally formed at the CZTSSe/Mo interface, betw...

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New insights into the Mo/Cu(In,Ga)Se2 interface in thin film solar cells: Formation and properties of the MoSe2 interfacial layer

Cited by 33 publications

References 24 publications

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Back and front contacts in kesterite solar cells: state-of-the-art and open questions

Physical routes for the synthesis of kesterite

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New insights into the Mo/Cu(In,Ga)Se2 interface in thin film solar cells: Formation and properties of the MoSe2 interfacial layer

Cited by 33 publications

References 24 publications

Selenium‐Graded Sb2(S1−xSex)3 for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Selenium‐Graded Sb2(S1−xSex)3 for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Back and front contacts in kesterite solar cells: state-of-the-art and open questions

Physical routes for the synthesis of kesterite

Contact Info

Product

Resources

About

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

Selenium‐Graded Sb₂(S_1−xSe_x)₃ for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%