In this study, solid solutions formed of SnO and CaO [termed (Sn:Ca)xO] are explored as potential solar active layers. The results indicate that a ratio of x = 7 : 1 leads to a fundamental direct bandgap of 1.56 eV. In order to promote the transport of excited charge carriers from within the active layer, appropriately aligned hole/electron transport layers need to be identified. To this end, a set of results are presented for the electronic band alignment of (Sn:Ca)7:1O with a selection of oxide transport layers, with and without oxygen vacancies. From this, it is recommended that a CaO/(Sn:Ca)7:1O/TiO2 device shows the most potential for an all-oxide solar cell.

1.
W.
Shockley
and
H. J.
Queisser
, “
Detailed balance limit of efficiency of p–n junction solar cells
,”
J. Appl. Phys.
32
(
3
),
510
519
(
1961
).
2.
S.
Rühle
, “
Tabulated values of the Shockley-Queisser limit for single junction solar cells
,”
Sol. Energy
130
,
139
147
(
2016
).
3.
S.
Rühle
,
A. Y.
Anderson
,
H.
Noa Barad
,
B.
Kupfer
,
Y.
Bouhadana
,
E.
Rosh-Hodesh
, and
A.
Zaban
, “
All-oxide photovoltaics
,”
J. Phys. Chem. Lett.
3
(
24
),
3755
3764
(
2012
).
4.
T.
Dimopoulos
,
All-Oxide Solar Cells
(
Elsevier Inc
.,
2018
).
5.
P. K.
Nayak
,
S.
Mahesh
,
H. J.
Snaith
, and
D.
Cahen
, “
Photovoltaic solar cell technologies: Analysing the state of the art
,”
Nat. Rev. Mater.
4
(
4
),
269
285
(
2019
).
6.
S.
Dubey
,
N. Y.
Jadhav
, and
B.
Zakirova
, “
Socio-economic and environmental impacts of silicon based photovoltaic (PV) technologies
,”
Energy Procedia
33
,
322
334
(
2013
).
7.
H. J.
Tchognia Nkuissi
,
F.
Kouadio Konan
,
B.
Hartiti
, and
J.-M.
Ndjaka
, “
Toxic Materials used in thin film photovoltaics and their impacts on environment
,”
Reliability and Ecological Aspects of Photovoltaic Modules
, (
IntechOpen
,
2020
), pp.
1
18
.
8.
M.
Coll
,
J.
Fontcuberta
,
M.
Althammer
,
M.
Bibes
,
H.
Boschker
,
A.
Calleja
,
G.
Cheng
,
M.
Cuoco
,
R.
Dittmann
,
B.
Dkhil
,
I. E.
Baggari
,
M.
Fanciulli
,
I.
Fina
,
E.
Fortunato
,
C.
Frontera
,
S.
Fujita
,
V.
Garcia
,
S. T. B.
Goennenwein
,
C. G.
Granqvist
,
J.
Grollier
,
R.
Gross
,
A.
Hagfeldt
,
G.
Herranz
,
K.
Hono
,
E.
Houwman
,
M.
Huijben
,
A.
Kalaboukhov
,
D. J.
Keeble
,
G.
Koster
,
L. F.
Kourkoutis
,
J.
Levy
,
M.
Lira-Cantu
,
J. L.
MacManus-Driscoll
,
J.
Mannhart
,
R.
Martins
,
S.
Menzel
,
T.
Mikolajick
,
M.
Napari
,
M. D.
Nguyen
,
G.
Niklasson
,
C.
Paillard
,
S.
Panigrahi
,
G.
Rijnders
,
F.
Sánchez
,
P.
Sanchis
,
S.
Sanna
,
D. G.
Schlom
,
U.
Schroeder
,
K. M.
Shen
,
A.
Siemon
,
M.
Spreitzer
,
H.
Sukegawa
,
R.
Tamayo
,
J.
van den Brink
,
N.
Pryds
, and
F.
Miletto Granozio
, “
Towards oxide electronics: A roadmap
,”
Appl. Surf. Sci.
482
,
1
93
(
2019
).
9.
N. T.
Taylor
,
F. H.
Davies
,
S. G.
Davies
,
C. J.
Price
, and
S. P.
Hepplestone
, “
The fundamental mechanism behind colossal permittivity in oxides
,”
Adv. Mater.
31
(
51
),
1904746
(
2019
).
10.
H.
Peng
,
A.
Bikowski
,
A.
Zakutayev
, and
S.
Lany
, “
Pathway to oxide photovoltaics via band-structure engineering of SnO
,”
APL Mater.
4
(
10
),
106103
(
2016
).
11.
K.
Niwa
,
I.
Yamai
, and
T.
Wada
, “
A study of tin oxides by x-ray diffraction method
,”
Bull. Chem. Soc. Jpn.
31
(
6
),
725
727
(
1958
).
12.
G.
Kresse
and
J.
Furthmüller
, “
Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
,”
Phys. Rev. B
54
(
16
),
11169
11186
(
1996
).
13.
G.
Kresse
and
J.
Furthmüller
, “
Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
,”
Comput. Mater. Sci.
6
(
1
),
15
50
(
1996
).
14.
J. P.
Perdew
,
K.
Burke
, and
M.
Ernzerhof
, “
Generalized gradient approximation made simple
,”
Phys. Rev. Lett.
77
(
18
),
3865
3868
(
1996
).
15.
A. V.
Krukau
,
O. A.
Vydrov
,
A. F.
Izmaylov
, and
G. E.
Scuseria
, “
Influence of the exchange screening parameter on the performance of screened hybrid functionals
,”
J. Chem. Phys.
125
(
22
),
224106
(
2006
).
16.
H. J.
Monkhorst
and
J. D.
Pack
, “
Special points for Brillouin-zone integrations
,”
Phys. Rev. B
13
(
12
),
5188
5192
(
1976
).
17.
K. T.
Delaney
,
N. A.
Spaldin
, and
C. G.
Van De Walle
, “
Theoretical study of Schottky-barrier formation at epitaxial rare-earth-metal/semiconductor interfaces
,”
Phys. Rev. B
81
(
16
),
165312
(
2010
).
18.
S. P.
Hepplestone
and
P. V.
Sushko
, “
Effect of metal intermixing on the Schottky barriers of Mo(100)/GaAs(100) interfaces
,”
J. Appl. Phys.
116
(
19
),
193703
(
2014
).
19.
N. T.
Taylor
,
F. H.
Davies
,
I.
EdwardMikel Rudkin
,
C. J.
Price
,
T. H.
Chan
, and
S. P.
Hepplestone
, “
ARTEMIS: Ab initio restructuring tool enabling the modelling of inter face structures
,”
Comput. Phys. Commun.
257
,
107515
(jul
2020
)page.
20.
Y.
Ogo
,
H.
Hiramatsu
,
K.
Nomura
,
H.
Yanagi
,
T.
Kamiya
,
M.
Hirano
, and
H.
Hosono
, “
p-channel thin-film transistor using p-type oxide semiconductor, SnO
,”
Appl. Phys. Lett.
93
(
3
),
032113
(
2008
).
21.
R. C.
Whited
,
C. J.
Flaten
, and
W. C.
Walker
, “
Exciton thermoreflectance of MgO and CaO
,”
Solid State Commun.
13
(
11
),
1903
1905
(
1973
).
22.
M.
Batzill
, “
Fundamental aspects of surface engineering of transition metal oxide photocatalysts
,”
Energy Environ. Sci.
4
(
9
),
3275
3286
(
2011
).
23.
T.
Mark
and
Z. H.
Greiner
, “
Lu. Thin-film metal oxides in organic semiconductor devices: Their electronic structures, work functions and interfaces
,”
NPG Asia Mater.
5
(
7
),
e55
(
2013
).
24.
J.
Kim
,
K.
Yamamoto
,
S.
Iimura
,
S.
Ueda
, and
H.
Hosono
, “
Electron affinity control of amorphous oxide semiconductors and its applicability to organic electronics
,”
Adv. Mater. Interfaces
5
(
23
),
1801307
(
2018
).
25.
L. R.
Fonseca
,
A. A.
Knizhnik
,
A. V.
Gavrikov
,
I. M.
Iskandarova
,
A. A.
Bagatur'yants
, and
B. V.
Potapkin
, “
Fermi pinning in metal-oxide-semiconductor structures results from low oxygen content at the metal-oxide interface
,” in
ECS Transactions
(
ECS
,
2007
), Vol.
4
, pp.
227
235
.
26.
M.
Ernzerhof
and
G. E.
Scuseria
, “
Assessment of the Perdew-Burke-Ernzerhof exchange-correlation functional
,”
J. Chem. Phys.
110
(
11
),
5029
5036
(mar
1999
).
27.
H.
Tang
,
F.
Lévy
,
H.
Berger
, and
P. E.
Schmid
, “
Urbach tail of anatase TiO2
,”
Phys. Rev. B
52
(
11
),
7771
7774
(
1995
).
28.
G. W.
Rubloff
, “
Far-ultraviolet reflectance spectra and the electronic structure of ionic crystals
,”
Phys. Rev. B
5
(
2
),
662
684
(
1972
).
29.
D. M.
Roessler
and
W. C.
Walker
, “
Electronic spectrum of crystalline lithium fluoride
,”
J. Phys. Chem. Solids
28
(
8
),
1507
1515
(
1967
).
30.
M.
Kröger
,
S.
Hamwi
,
J.
Meyer
,
T.
Riedl
,
W.
Kowalsky
, and
A.
Kahn
, “
Role of the deep-lying electronic states of MoO3 in the enhancement of hole-injection in organic thin films
,”
Appl. Phys. Lett.
95
(
12
),
123301
(
2009
).
31.
J.
Bardeen
, “
Surface states and rectification at a metal semi-conductor contact
,”
Phys. Rev.
71
(
10
),
717
727
(
1947
).
32.
X.
Pan
,
M. Q.
Yang
,
X.
Fu
,
N.
Zhang
, and
Y. J.
Xu
, “
Defective TiO2 with oxygen vacancies: Synthesis, properties and photocatalytic applications
,”
Nanoscale
5
(
9
),
3601
3614
(
2013
).
33.
B. J.
Morgan
and
G. W.
Watson
, “
Intrinsic n-type defect formation in TiO2: A comparison of rutile and anatase from GGA+U calculations
,”
J. Phys. Chem. C
114
(
5
),
2321
2328
(
2010
).
34.
N. T.
Taylor
,
A.
Galbiati
,
M.
Saavedra
, and
S. P.
Hepplestone
(
2020
). “
Calcium-stannous oxide solid solutions for solar devices (dataset)
” University of Exeter's Institutional, https://doi.org/10.24378/exe.2663.

Supplementary Material

You do not currently have access to this content.