A Temporary Barrier Effect of the Alloy Layer During Selenization: Tailoring the Thickness of MoSe2 for Efficient Cu2ZnSnSe4 Solar Cells

Li, Jianjun; Zhang, Yi; Zhao, Wei; Nam, Dahyun; Cheong, Hyeonsik; Wu, Li; Zhou, Zhiqiang; Sun, Yun

doi:10.1002/aenm.201402178

Cited by 148 publications

(108 citation statements)

References 30 publications

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“…[20][21][22] However, this may be negligible since the thickness of Mo(Se,S) 2 is only ≈12% of the Mo thickness (0.5 µm) in Z6 ( Figure S3, Supporting Information).…”

Section: Discussion Of Secondary Phasesmentioning

confidence: 96%

“…[20][21][22] Similar to the situation on Cu(In,Ga)Se 2 (CIGS) solar cells, a thin (≈10 nm) interfacial MoSe 2 layer is helpful to improve the adhesion between the CZTSSe fi lm and the Mo back contact and to help form an ohmic contact. [ 23 ] However, an over-thick MoSe 2 layer will deteriorate the electrical contact and increases R SL .…”

Section: Introductionmentioning

confidence: 94%

“…[ 22 ] Both methods can signifi cantly reduce R S , with method (1) reducing the thickness of MoSe 2 layer to <10 nm. [ 20 ] In this work, we focus on the second FF loss factor, i.e., the series resistance, and discuss various sources of R S in our highperformance kesterite devices with different E g (1.0-1.5 eV) or varying S/(S + Se) ratio. We perform color J-V and high intensity color J SC -V OC to investigate the electrical characteristics of the front (CdS/CZTSSe) and rear (CZTSSe/Mo) junction.…”

Section: Introductionmentioning

confidence: 99%

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Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Tai

Gunawan

Kuwahara

et al. 2015

Advanced Energy Materials

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of 8.4% has a V OC,def of 789 mV. [ 3 ] The V OC,def issue in CZTSSe solar cells has been investigated extensively and various intrinsic factors have been proposed: low dielectric constant, [ 4,5 ] fl uctuating potential of conduction and valence bands, [5][6][7] high defect density, [ 8 ] deep defects, and nonradiative channels in the CZTSSe absorbers. [ 9 ] Given the signifi cant increase of V OC,def with S/(S + Se) ratio, there could be additional extrinsic factors related to S-content to explain the high V OC,def in CZTSSe with high S/(S + Se) ratio (e.g., formation of secondary phases).The second pressing issue in kesterite technology is the relatively low device fi ll factor (FF). [ 10 ] For example, the current champion CZTSSe device has FF = 69.8% [ 1 ] compared to FF = 79.4% in the champion Cu(In,Ga)Se 2 solar cell with the same E g of 1.13 eV. [ 11 ] In general, there are several mechanisms of FF loss in solar cells (in approximate order of their negative impact in kesterite devices): (1) V OC and ideality factor ( n ) loss; [ 12 ] (2) series resistance ( R S ) loss; [ 12 ] (3) voltage-dependent collection effi ciency (VDCE) loss [ 13 ] and (4) shunt conductance ( G S ) loss. [ 12 ] The nature of the V OC defi cit problem has been discussed in refs. [ 5 ] and [ 6 ] , and therefore we focus on the second factor ( R S loss) in this work. R S is usually extracted from the light-JV (LJV) curve, and thus denoted by R SL . The R SL values of the champion CZTSe, CZTSSe, and CZTS solar cells are 0.5, [ 2 ] 0.7, [ 1 ] and 1.4 Ω cm 2 , [ 3 ] respectively, while other literature also report a high R SL for CZTS. [14][15][16] The extraordinarily high R SL could be due to the formation of (high E g ) interfacial secondary phases, which act as a charge blocking

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“…[20][21][22] However, this may be negligible since the thickness of Mo(Se,S) 2 is only ≈12% of the Mo thickness (0.5 µm) in Z6 ( Figure S3, Supporting Information).…”

Section: Discussion Of Secondary Phasesmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Tai

Gunawan

Kuwahara

et al. 2015

Advanced Energy Materials

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“…The detailed selenization process was described in refs. , Before the CZTSe films were treated by AS vapor, the CZTSe films were immersed in 25 wt.% NH 3 · H 2 O solution for 5 min to etch the oxide compounds at the surfaces of absorbers and then dried by nitrogen. Then the etched absorbers were treated with (NH 4 ) 2 S vapor.…”

Section: Methodsmentioning

confidence: 99%

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

et al. 2018

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The interfaces are very important for kesterite‐structured solar cells. In this study, a facile room temperature chemical sulfurization process is developed to modify the surface of the CZTSe films, which can prevent the decomposition of kesterite film at high temperature during the traditional sulfurization process and thus introducing the deep defects in the absorber layer. It is found that the (NH4)2S vapor sulfurizes the surfaces of the CZTSe thin films previously etched by ammonia. Consequently, the surface defects are passivated by the incorporated sulfur, and the interfacial band alignment is improved at the junction. The open circuit voltage (VOC) of the solar cell device is improved from 364 mV to 406 mV, with the cell efficiency increased to 9.04% when the (NH4)2S vapor treatment time is optimized at 25 min. This study affords a new perspective for enhancing the performance of kesterite‐based thin film solar cells using a facile surface sulfurization approach.

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“…Another demonstrated route has been the soft alloying of the metallic precursors before selenization [10].…”

Section: Introductionmentioning

confidence: 99%

Modeling the Back Contact of Cu₂ZnSnSe₄Solar Cells

Cozza

Ruiz

Duché

et al. 2016

IEEE J. Photovoltaics

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In this paper, we analyze the theoretical impact of the Molybdenum (Mo) back contact and the MoSe 2 interfacial layer on the performances of a Cu 2 ZnSnSe 4 (CZTSe)-based solar cell. MoSe 2 layers are formed spontaneously in the Mo/CZTSe interface during the annealing of the absorber, but disagreeing interpretations about their actual role in affecting the device figures of merit (V O C , J S C , FF, and η) have been proposed in the literature. In our approach, we have simulated three structures presenting different conditions at the back contact: ideal-contact/CZTSe (flat-band), Mo/CZTSe, and Mo/MoSe 2 /CZTSe. For these three layers, an accurate explanation of the selection of critical material parameters is given. The numerical simulations, performed with SCAPS 3.2.01, show that the low values of Mo work function (≤ 4.95 eV) would have a strong detrimental effect on the V O C and FF of the cell if no interfacial layers were present at the Mo/CZTSe interface. On the other hand, a beneficial effect of the MoSe 2 layer on the V O C of the device is demonstrated when this layer is included in the structure. This trend is confirmed by experimental measurements. The expected band diagram of the full ZnO/CdS/CZTSe/MoSe 2 /Mo structure is provided.

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A Temporary Barrier Effect of the Alloy Layer During Selenization: Tailoring the Thickness of MoSe₂ for Efficient Cu₂ZnSnSe₄ Solar Cells

Cited by 148 publications

References 30 publications

Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

Modeling the Back Contact of Cu₂ZnSnSe₄Solar Cells

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A Temporary Barrier Effect of the Alloy Layer During Selenization: Tailoring the Thickness of MoSe2 for Efficient Cu2ZnSnSe4 Solar Cells

Cited by 148 publications

References 30 publications

Fill Factor Losses in Cu2ZnSn(SxSe1−x)4 Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Fill Factor Losses in Cu2ZnSn(SxSe1−x)4 Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

Modeling the Back Contact of Cu2ZnSnSe4Solar Cells

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Product

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A Temporary Barrier Effect of the Alloy Layer During Selenization: Tailoring the Thickness of MoSe₂ for Efficient Cu₂ZnSnSe₄ Solar Cells

Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Fill Factor Losses in Cu₂ZnSn(S_xSe_1−x)₄ Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Modeling the Back Contact of Cu₂ZnSnSe₄Solar Cells