Atomic‐Layer‐Deposited Aluminum and Zirconium Oxides for Surface Passivation of TiO2 in High‐Efficiency Organic Photovoltaics. Issue 15 (23rd June 2014)

• Record Type: Journal Article
• Authors: 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; Argitis, Panagiotis
• Is Part Of: Advanced energy materials. Volume 4:Issue 15(2014)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2014-06-23
• Subjects: Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201400214
• Languages: English
• ISSNs: 1614-6832

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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.</p> </abstract>