Synthesis and characterization of novel oxygenated CdSe window layer for CdTe thin film solar cells

Bao, Zheng; Liu, Longxiao; Yang, Xiaoyan; Tang, Ping; Yang, Ke; Lu, Hongting; He, Siying; Liu, Jiyang; Liu, Xiaolan; Li, Bing

doi:10.1016/j.mssp.2017.01.003

Cited by 22 publications

(9 citation statements)

References 22 publications

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“…[ 8 ] These defects can be found both in the CdSe x Te 1− x layer [ 9–12 ] and at the SnO 2 :F (FTO)/CdSe front interface. [ 13,14 ] Although many attempts have been made to improve the front interface quality, [ 15,16 ] so far no efforts solve the dilemma and all the cells show efficiency less than 15%.…”

Section: Introductionmentioning

confidence: 99%

Improving CdTe‐Based Thin‐Film Solar Cell Efficiency with the Oxygenated CdSe Layer Prepared by Sputtering Process

Zhou²,

Qin³

et al. 2020

Physica Status Solidi (a)

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Sputtered CdSe window layer can improve the short-circuit current density (J sc) of CdTe-based thin-film solar cell, however, meanwhile degrade the open-circuit voltage (V oc) and fill factor (FF). Herein, an oxygenation process is introduced during CdSe sputtering to improve this window layer's property for better device performance. The influence of oxygen on the CdSe is similar as the effect of oxygen on CdS. Incorporation of oxygen into the CdSe film promotes the formation of CdSeO 3 phase. Both V oc and FF of the CdTe solar cells are improved due to the formation of CdSeO 3 , and high efficiency (Eff.) of 18.6% is achieved. Efficiency improvement at module level is also demonstrated after applying the CdSe:O process in production line. This progress contributes to the CdTe-based thin-film module production for further efficiency improvement and cost reduction.

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Section: Introductionmentioning

confidence: 99%

Improving CdTe‐Based Thin‐Film Solar Cell Efficiency with the Oxygenated CdSe Layer Prepared by Sputtering Process

Zhou²,

Qin³

et al. 2020

Physica Status Solidi (a)

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“…Despite the increased J SC , Cd(Se,Te) solar cells did not immediately realize significantly improved PCEs due to the compromised open-circuit voltage (V OC ) 3,8,9 . For a long time, only First Solar Inc, a leading Cd(Se,Te) module manufacturer, was able to fabricate Cd(Se,Te) solar cells showing PCEs significantly higher than that of CdTe solar cells 10 .…”

mentioning

confidence: 99%

20%-efficient polycrystalline Cd(Se,Te) thin-film solar cells with compositional gradient near the front junction

Bista

Awni

et al. 2022

Nat Commun

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Bandgap gradient is a proven approach for improving the open-circuit voltages (VOCs) in Cu(In,Ga)Se2 and Cu(Zn,Sn)Se2 thin-film solar cells, but has not been realized in Cd(Se,Te) thin-film solar cells, a leading thin-film solar cell technology in the photovoltaic market. Here, we demonstrate the realization of a bandgap gradient in Cd(Se,Te) thin-film solar cells by introducing a Cd(O,S,Se,Te) region with the same crystal structure of the absorber near the front junction. The formation of such a region is enabled by incorporating oxygenated CdS and CdSe layers. We show that the introduction of the bandgap gradient reduces the hole density in the front junction region and introduces a small spike in the band alignment between this and the absorber regions, effectively suppressing the nonradiative recombination therein and leading to improved VOCs in Cd(Se,Te) solar cells using commercial SnO2 buffers. A champion device achieves an efficiency of 20.03% with a VOC of 0.863 V.

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“…This is due to the small bandgap (E g ) of CdS film and large lattice mismatch between CdS and CdTe [10]. Using CdSe window layer can enhance J sc [11][12][13][14] but the open circuit voltage (V OC ) and fill factor (FF) decrease [11,12]. The work of ours and others shows that using CdS/CdSe composite window layer can enhance J sc and maintain V OC and thus improve the device efficiency [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 88%

Properties of CdSe1−xSx films by magnetron sputtering and their role in CdTe solar cells

Wang

et al. 2020

J Mater Sci: Mater Electron

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CdS/CdSe composite window layer is a better candidate than CdS or CdSe single layer for CdTe solar cells. In order to find the underlying reason, the properties of co-sputtered CdSe 1-x S x thin films with different compositions (0 x 1) were examined. XRD patterns show that all CdSe 1-x S x films (0 x 1) are polycrystalline with hexagonal structures and the prominent peak position shows an increasing trend with the increase of x. This suggests that CdSe 1-x S x window layer with a gradient composition, formed during the hightemperature growth and heat treatment of CdTe films, has the gradient lattice constant, meaning the less defect density. This is beneficial to the device performance. Hall measurements show that CdS 1-x Se x films (x C 0.772) are n-type semiconductors with carrier concentrations ranging from 10 15 cm -3 to 10 16 cm -3 . It reveals that CdS/CdSe bi-layers can form a strong built-in electric field with CdTe layer as CdS does. The electronic band structure of CdSe 1-x S x window layer with a gradient composition suggests that the spikes formed in the conduction band are lower than 0.3 eV, which would not impede the electron transport. The valence band alignment is beneficial for the hole transport. Therefore, an appropriate band alignment can be formed between CdSe 1-x S x and CdTe layers. These results reveal that CdSe 1-x S x film is a good candidate as the window layer for high-efficiency CdTe solar cells considering its structural, optical and electrical properties as well as its electronic structure.

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Synthesis and characterization of novel oxygenated CdSe window layer for CdTe thin film solar cells

Cited by 22 publications

References 22 publications

Improving CdTe‐Based Thin‐Film Solar Cell Efficiency with the Oxygenated CdSe Layer Prepared by Sputtering Process

Improving CdTe‐Based Thin‐Film Solar Cell Efficiency with the Oxygenated CdSe Layer Prepared by Sputtering Process

20%-efficient polycrystalline Cd(Se,Te) thin-film solar cells with compositional gradient near the front junction

Properties of CdSe1−xSx films by magnetron sputtering and their role in CdTe solar cells

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