A closer look into metastable effects of Cu(In,Ga)Se<sub>2</sub> solar cells

Lavrenko, Tetiana; Walter, Thomas; Plesz, Balázs

doi:10.1002/pssc.201600197

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…Wavelengths in the UV are not known to harm CIGS, but rather induce metastable effects depending on the absorber/buffer interface. [21][22][23][24] Additionally, the intensity of plasma radiation does barely scale with applied power, but rather with pressure. Together, this leads to the conclusion that the damage is not radiation based.…”

Section: Influence Of Sputter Parameters On Carrier Lifetimementioning

confidence: 99%

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

Hertwig

Nishiwaki

2022

Solar RRL

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Herein, the detrimental impact of radio frequency (RF)‐sputtering on bare Cu(In,Ga)Se2 photovoltaic absorbers in view of vacuum‐deposited buffer layers is evaluated, and the possible mitigation strategies are explored. Carrier lifetimes are measured using time‐resolved photoluminescence before and after buffer deposition and exposure to the plasma environment. When directly applied on bare Cu(In,Ga)Se2 absorbers, RF‐sputtering is severely limiting the device performance, with oxygen ions emanating from the target having a stronger effect than argon ions from the process gas. The possibilities to avoid sputter damage by atomic layer deposited Zn1−xMgxO and chemical bath deposited CdS buffer layers are shown, and the ability of the latter to restore damaged surfaces is highlighted. Absorber performance is also investigated for absorbers stored in air, N2, or ultra‐high vacuum. The reduction in carrier lifetime is reflected in the reduced open‐circuit voltage of solar cells. SCAPS simulations are used to investigate possibilities to minimize the effect of sputter damage. Finally, options on how to minimize sputter damage during buffer deposition as well as on how to modify the absorber to be less sensitive are discussed.

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Section: Influence Of Sputter Parameters On Carrier Lifetimementioning

confidence: 99%

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

Hertwig

Nishiwaki

2022

Solar RRL

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“…the lower efficiencies observed after HLS using apparatus #1 are attributable to dark heat-soaking effects. [20][21][22] Although a clear understanding of metastable acceptor phenomena in…”

Section: Datementioning

confidence: 99%

An over 18%-efficient completely buffer-free Cu(In,Ga)Se₂ solar cell

Ishizuka¹,

Nishinaga²,

Koida³

et al. 2018

Appl. Phys. Express

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In this letter, an independently certified photovoltaic efficiency of 18.4% demonstrated from a completely buffer-layer-free Cu(In,Ga)Se2 (CIGS) solar cell is reported. A Si-doped CIGS thin film was used as the photoabsorber layer and a conductive B-doped ZnO (BZO) front electrode layer was directly deposited on the CIGS layer. Metastable acceptor activation by heat-light soaking treatment was performed to maximize the efficiency. The results presented here are expected to serve as a benchmark for simplified-structure CIGS devices as well as a reference for discussions on the role of buffer layers used in conventional CIGS solar cells.

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Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

Ishizuka

Nishinaga

Iioka

et al. 2018

Advanced Energy Materials

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In this communication, novel and simplified structure Cu(In,Ga)Se2 (CIGS) solar cells, which nominally consist of only a CIGS photoabsorber layer sandwiched between back and front contact layers but yet demonstrate high photovoltaic efficiencies, are reported. To realize this accomplishment, Si‐doped CIGS films grown by the three‐stage coevaporation method, B‐doped ZnO transparent conductive oxide front contact layers deposited by chemical vapor deposition, and heat–light soaking treatments are used. Si‐doping of CIGS films is found to modify the film surfaces and grain boundary properties and also affect the alkali metal distribution profiles in CIGS films. These effects are expected to contribute to improvements in buffer‐free CIGS device performance. Heat–light soaking treatments, which are occasionally performed to improve conventional buffer‐based CIGS device performance, are found to be also effective in enhancing buffer‐free CIGS photovoltaic efficiencies. This result suggests that the mechanism behind the beneficial effects of heat–light soaking treatments originates from CIGS bulk issues and is independent of the buffer materials. Consequently, over 16.5% efficiencies, including an independently certified value, are demonstrated from completely buffer‐free CIGS photovoltaic devices.

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A closer look into metastable effects of Cu(In,Ga)Se₂ solar cells

Cited by 4 publications

References 13 publications

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

An over 18%-efficient completely buffer-free Cu(In,Ga)Se₂ solar cell

Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

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A closer look into metastable effects of Cu(In,Ga)Se2 solar cells

Cited by 4 publications

References 13 publications

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se2 Absorbers for Photovoltaic Applications

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se2 Absorbers for Photovoltaic Applications

An over 18%-efficient completely buffer-free Cu(In,Ga)Se2 solar cell

Si‐Doped Cu(In,Ga)Se2 Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

Contact Info

Product

Resources

About

A closer look into metastable effects of Cu(In,Ga)Se₂ solar cells

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

Investigation and Mitigation of Sputter Damage on Co‐Evaporated Cu(In,Ga)Se₂ Absorbers for Photovoltaic Applications

An over 18%-efficient completely buffer-free Cu(In,Ga)Se₂ solar cell

Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer