Co-Solvent Enhanced Zinc Oxysulfide Buffer Layers in Kesterite Copper Zinc Tin Selenide Solar Cells

K. Xerxes Steirer; Rebekah L. Garris; Jian V. Li; Michael J. Dzara; Paul F. Ndione; Kannan Ramanathan; Ingrid Repins; Glenn Teeter; Craig L. Perkins

doi:10.1039/C5CP01607J

Co-Solvent Enhanced Zinc Oxysulfide Buffer Layers in Kesterite Copper Zinc Tin Selenide Solar Cells

K. Xerxes Steirer, Rebekah L. Garris, Jian V. Li, Michael J. Dzara, Paul F. Ndione, Kannan Ramanathan, Ingrid Repins, Glenn Teeter, Craig L. Perkins

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Abstract

A co-solvent, dimethylsulfoxide (DMSO), is added to the aqueous chemical "bath" deposition (CBD) process used to grow ZnOS buffer layers for thin film Cu₂ZnSnSe₄ (CZTSe) solar cells. Device performance improves markedly as fill factors increase from 0.17 to 0.51 upon the co-solvent addition. X-ray photoelectron spectroscopy (XPS) analyses are presented for quasi-in situ CZTSe/CBD-ZnOS interfaces prepared under an inert atmosphere and yield valence band offsets equal to -1.0 eV for both ZnOS preparations. When combined with optical band gap data, conduction band offsets exceed 1 eV for the water and the water/DMSO solutions. XPS measurements show increased downward band bending in the CZTSe absorber layer when the ZnOS buffer layer is deposited from water only. Admittance spectroscopy data shows that the ZnOS deposited from water increases the built-in potential (V_bi) yet these solar cells perform poorly compared to those made with DMSO added. The band energy offsets imply an alternate form of transport through this junction. Possible mechanisms are discussed, which circumvent the otherwise large conduction band spike between CZTSe and ZnOS, and improve functionality with the low-band gap absorber, CZTSe (E_g = 0.96 eV).

Original language	American English
Pages (from-to)	15355-15364
Number of pages	10
Journal	Physical Chemistry Chemical Physics
Volume	17
Issue number	23
DOIs	https://doi.org/10.1039/C5CP01607J https://doi.org/10.1039/c5cp01607j
State	Published - 2015

Bibliographical note

Publisher Copyright:
© 2015 the Owner Societies.

NREL Publication Number

NREL/JA-5K00-63824

Keywords

admittance
buffers
conduction band
Cu2ZnSnSe4
CZTS
CZTSe
defects
kesterite
photoelectron spectroscopic (UPS)
solar cells
UPS
UV-VIS
XPS

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title = "Co-Solvent Enhanced Zinc Oxysulfide Buffer Layers in Kesterite Copper Zinc Tin Selenide Solar Cells",

abstract = "A co-solvent, dimethylsulfoxide (DMSO), is added to the aqueous chemical {"}bath{"} deposition (CBD) process used to grow ZnOS buffer layers for thin film Cu2ZnSnSe4 (CZTSe) solar cells. Device performance improves markedly as fill factors increase from 0.17 to 0.51 upon the co-solvent addition. X-ray photoelectron spectroscopy (XPS) analyses are presented for quasi-in situ CZTSe/CBD-ZnOS interfaces prepared under an inert atmosphere and yield valence band offsets equal to -1.0 eV for both ZnOS preparations. When combined with optical band gap data, conduction band offsets exceed 1 eV for the water and the water/DMSO solutions. XPS measurements show increased downward band bending in the CZTSe absorber layer when the ZnOS buffer layer is deposited from water only. Admittance spectroscopy data shows that the ZnOS deposited from water increases the built-in potential (Vbi) yet these solar cells perform poorly compared to those made with DMSO added. The band energy offsets imply an alternate form of transport through this junction. Possible mechanisms are discussed, which circumvent the otherwise large conduction band spike between CZTSe and ZnOS, and improve functionality with the low-band gap absorber, CZTSe (Eg = 0.96 eV).",

keywords = "admittance, buffers, conduction band, Cu2ZnSnSe4, CZTS, CZTSe, defects, kesterite, photoelectron spectroscopic (UPS), solar cells, UPS, UV-VIS, XPS",

author = "Steirer, {K. Xerxes} and Garris, {Rebekah L.} and Li, {Jian V.} and Dzara, {Michael J.} and Ndione, {Paul F.} and Kannan Ramanathan and Ingrid Repins and Glenn Teeter and Perkins, {Craig L.}",

note = "Publisher Copyright: {\textcopyright} 2015 the Owner Societies.",

year = "2015",

doi = "10.1039/C5CP01607J",

language = "American English",

volume = "17",

pages = "15355--15364",

journal = "Physical Chemistry Chemical Physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

number = "23",

}

TY - JOUR

T1 - Co-Solvent Enhanced Zinc Oxysulfide Buffer Layers in Kesterite Copper Zinc Tin Selenide Solar Cells

AU - Steirer, K. Xerxes

AU - Garris, Rebekah L.

AU - Li, Jian V.

AU - Dzara, Michael J.

AU - Ndione, Paul F.

AU - Ramanathan, Kannan

AU - Repins, Ingrid

AU - Teeter, Glenn

AU - Perkins, Craig L.

PY - 2015

Y1 - 2015

N2 - A co-solvent, dimethylsulfoxide (DMSO), is added to the aqueous chemical "bath" deposition (CBD) process used to grow ZnOS buffer layers for thin film Cu2ZnSnSe4 (CZTSe) solar cells. Device performance improves markedly as fill factors increase from 0.17 to 0.51 upon the co-solvent addition. X-ray photoelectron spectroscopy (XPS) analyses are presented for quasi-in situ CZTSe/CBD-ZnOS interfaces prepared under an inert atmosphere and yield valence band offsets equal to -1.0 eV for both ZnOS preparations. When combined with optical band gap data, conduction band offsets exceed 1 eV for the water and the water/DMSO solutions. XPS measurements show increased downward band bending in the CZTSe absorber layer when the ZnOS buffer layer is deposited from water only. Admittance spectroscopy data shows that the ZnOS deposited from water increases the built-in potential (Vbi) yet these solar cells perform poorly compared to those made with DMSO added. The band energy offsets imply an alternate form of transport through this junction. Possible mechanisms are discussed, which circumvent the otherwise large conduction band spike between CZTSe and ZnOS, and improve functionality with the low-band gap absorber, CZTSe (Eg = 0.96 eV).

AB - A co-solvent, dimethylsulfoxide (DMSO), is added to the aqueous chemical "bath" deposition (CBD) process used to grow ZnOS buffer layers for thin film Cu2ZnSnSe4 (CZTSe) solar cells. Device performance improves markedly as fill factors increase from 0.17 to 0.51 upon the co-solvent addition. X-ray photoelectron spectroscopy (XPS) analyses are presented for quasi-in situ CZTSe/CBD-ZnOS interfaces prepared under an inert atmosphere and yield valence band offsets equal to -1.0 eV for both ZnOS preparations. When combined with optical band gap data, conduction band offsets exceed 1 eV for the water and the water/DMSO solutions. XPS measurements show increased downward band bending in the CZTSe absorber layer when the ZnOS buffer layer is deposited from water only. Admittance spectroscopy data shows that the ZnOS deposited from water increases the built-in potential (Vbi) yet these solar cells perform poorly compared to those made with DMSO added. The band energy offsets imply an alternate form of transport through this junction. Possible mechanisms are discussed, which circumvent the otherwise large conduction band spike between CZTSe and ZnOS, and improve functionality with the low-band gap absorber, CZTSe (Eg = 0.96 eV).

KW - admittance

KW - buffers

KW - conduction band

KW - Cu2ZnSnSe4

KW - CZTS

KW - CZTSe

KW - defects

KW - kesterite

KW - photoelectron spectroscopic (UPS)

KW - solar cells

KW - UPS

KW - UV-VIS

KW - XPS

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U2 - 10.1039/C5CP01607J

DO - 10.1039/C5CP01607J

M3 - Article

AN - SCOPUS:84930679539

SN - 1463-9076

VL - 17

SP - 15355

EP - 15364

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 23

ER -

Co-Solvent Enhanced Zinc Oxysulfide Buffer Layers in Kesterite Copper Zinc Tin Selenide Solar Cells

Abstract

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NREL Publication Number

Keywords

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