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Atomic-layer-deposited aluminum and zirconium oxides for surface passivation of TiO2 in high-efficiency organic photovoltaics

Atomic-layer-deposited aluminum and zirconium oxides for surface passivation of TiO2 in high-efficiency organic photovoltaics
Atomic-layer-deposited aluminum and zirconium oxides for surface passivation of TiO2 in high-efficiency organic photovoltaics

The reduction in electronic recombination losses by the passivation of surfaces is a key factor enabling high-efficiency solar cells. Here a strategy to passivate surface trap states of TiO2 films used as cathode interlayers in organic photovoltaics (OPVs) through applying alumina (Al2O3) or zirconia (ZrO2) insulating nanolayers by thermal atomic layer deposition (ALD) is investigated. The results suggest that the surface traps in TiO2 are oxygen vacancies, which cause undesirable recombination and high electron extraction barrier, reducing the open-circuit voltage and the short-circuit current of the complete OPV device. It is found that the ALD metal oxides enable excellent passivation of the TiO2 surface followed by a downward shift of the conduction band minimum. OPV devices based on different photoactive layers and using the passivated TiO2 electron extraction layers exhibit a significant enhancement of more than 30% in their power conversion efficiencies compared to their reference devices without the insulating metal oxide nanolayers. This is a result of significant suppression of charge recombination and enhanced electron extraction rates at the TiO2/ALD metal oxide/organic interface.

alumina, atomic layer deposition, organic photovoltaic devices, surface passivation, titanium oxide, zirconia
1614-6832
1-12
Vasilopoulou, Maria
aad1381e-d091-4090-8c7c-b74bed22393d
Georgiadou, Dimitra G.
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Soultati, Anastasia
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Boukos, Nikos
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Gardelis, Spyros
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Palilis, Leonidas C.
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Fakis, Mihalis
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Skoulatakis, Georgios
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Kennou, Stella
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Botzakaki, Martha
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Georga, Stavroula
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Krontiras, Christoforos A.
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Auras, Florian
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Fattakhova-Rohlfing, Dina
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Bein, Thomas
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Papadopoulos, Theodoros A.
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Davazoglou, Dimitrios
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Argitis, Panagiotis
ab9c4ea6-3dd2-4e34-935d-81bfb360f358
Vasilopoulou, Maria
aad1381e-d091-4090-8c7c-b74bed22393d
Georgiadou, Dimitra G.
84977176-3678-4fb3-a3dd-2044a49c853b
Soultati, Anastasia
75205fde-50fc-473e-ad72-ab0b3c6b2cb9
Boukos, Nikos
ae6ffb1e-b138-485e-90d1-10242514c6c7
Gardelis, Spyros
e1c19249-ca1b-44c3-bb48-3cf76362f388
Palilis, Leonidas C.
b09e9554-54da-4be5-aa08-bda894e2b86f
Fakis, Mihalis
ed01170e-ba9c-48d8-87d3-02a05ad0eff0
Skoulatakis, Georgios
287f0311-f338-4c6f-b834-7a8e6f3fc495
Kennou, Stella
7ca6a6bd-6a05-4110-b3da-c8807f798370
Botzakaki, Martha
bb635074-3055-4851-9dda-4c4e527393e1
Georga, Stavroula
79b4f39f-de54-4831-afba-7892d3deeea2
Krontiras, Christoforos A.
9a122662-e56f-44d6-a021-7a6ed75f992c
Auras, Florian
a56e7a96-fe76-4b9e-acd0-209f720a0a3e
Fattakhova-Rohlfing, Dina
acea310a-e3d0-497d-a663-b9a97fcf379f
Bein, Thomas
90cb2c47-9fa6-463e-9a86-40503461ecc2
Papadopoulos, Theodoros A.
ba6a1607-2999-44b5-9f5c-d4cd7658ecbf
Davazoglou, Dimitrios
a946cf5d-287a-4734-ba55-b180ab4525ed
Argitis, Panagiotis
ab9c4ea6-3dd2-4e34-935d-81bfb360f358

Vasilopoulou, Maria, Georgiadou, Dimitra G., Soultati, Anastasia, Boukos, Nikos, Gardelis, Spyros, Palilis, Leonidas C., Fakis, Mihalis, Skoulatakis, Georgios, Kennou, Stella, Botzakaki, Martha, Georga, Stavroula, Krontiras, Christoforos A., Auras, Florian, Fattakhova-Rohlfing, Dina, Bein, Thomas, Papadopoulos, Theodoros A., Davazoglou, Dimitrios and Argitis, Panagiotis (2014) Atomic-layer-deposited aluminum and zirconium oxides for surface passivation of TiO2 in high-efficiency organic photovoltaics. Advanced Energy Materials, 4 (15), 1-12, [1400214]. (doi:10.1002/aenm.201400214).

Record type: Article

Abstract

The reduction in electronic recombination losses by the passivation of surfaces is a key factor enabling high-efficiency solar cells. Here a strategy to passivate surface trap states of TiO2 films used as cathode interlayers in organic photovoltaics (OPVs) through applying alumina (Al2O3) or zirconia (ZrO2) insulating nanolayers by thermal atomic layer deposition (ALD) is investigated. The results suggest that the surface traps in TiO2 are oxygen vacancies, which cause undesirable recombination and high electron extraction barrier, reducing the open-circuit voltage and the short-circuit current of the complete OPV device. It is found that the ALD metal oxides enable excellent passivation of the TiO2 surface followed by a downward shift of the conduction band minimum. OPV devices based on different photoactive layers and using the passivated TiO2 electron extraction layers exhibit a significant enhancement of more than 30% in their power conversion efficiencies compared to their reference devices without the insulating metal oxide nanolayers. This is a result of significant suppression of charge recombination and enhanced electron extraction rates at the TiO2/ALD metal oxide/organic interface.

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More information

e-pub ahead of print date: 23 June 2014
Published date: 1 October 2014
Keywords: alumina, atomic layer deposition, organic photovoltaic devices, surface passivation, titanium oxide, zirconia

Identifiers

Local EPrints ID: 440494
URI: http://eprints.soton.ac.uk/id/eprint/440494
ISSN: 1614-6832
PURE UUID: cf985d92-1a0c-4fa5-90c2-f74595633e55
ORCID for Dimitra G. Georgiadou: ORCID iD orcid.org/0000-0002-2620-3346

Catalogue record

Date deposited: 05 May 2020 16:42
Last modified: 06 Jun 2024 02:07

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Contributors

Author: Maria Vasilopoulou
Author: Anastasia Soultati
Author: Nikos Boukos
Author: Spyros Gardelis
Author: Leonidas C. Palilis
Author: Mihalis Fakis
Author: Georgios Skoulatakis
Author: Stella Kennou
Author: Martha Botzakaki
Author: Stavroula Georga
Author: Christoforos A. Krontiras
Author: Florian Auras
Author: Dina Fattakhova-Rohlfing
Author: Thomas Bein
Author: Theodoros A. Papadopoulos
Author: Dimitrios Davazoglou
Author: Panagiotis Argitis

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