Article, 2024

Tuning Surface Defect States in Sputtered Titanium Oxide Electron Transport Layers for Enhanced Stability of Organic Photovoltaics

ACS Applied Materials & Interfaces, ISSN 1944-8252, 1944-8244, Volume 16, 13, Pages 16580-16588, 10.1021/acsami.4c00056

Contributors

Ahmadpour, Mehrad 0000-0001-9722-4163 [1] Ahmad, Mariam 0000-0002-1114-8073 [1] Prete, Michela 0000-0003-0389-6300 [1] Hansen, John Lundsgaard [2] Miakota, Denys I 0000-0002-3723-915X [3] Greenbank, William A 0000-0002-1772-5732 [1] Zheng, Yunlin Jacques [4] Top, Michiel [5] Ebel, Thomas 0000-0001-8473-4471 [1] Rubahn, Horst-Günter [1] Turkovic, Vida 0000-0001-5608-1362 [1] Canulescu, Stela 0000-0003-3786-2598 [3] Witkowski, Nadine 0000-0002-7583-1218 [4] Madsen, Morten 0000-0001-6503-0479 (Corresponding author) [1]

Affiliations

  1. [1] University of Southern Denmark
    2. [NORA names: SDU University of Southern Denmark; University; Denmark; Europe, EU; Nordic; OECD];
  2. [2] Aarhus University
    3. [NORA names: AU Aarhus University; University; Denmark; Europe, EU; Nordic; OECD];
  3. [3] Technical University of Denmark
    4. [NORA names: DTU Technical University of Denmark; University; Denmark; Europe, EU; Nordic; OECD];
  4. [4] Paris Institute of Nanosciences
    5. [NORA names: France; Europe, EU; OECD];
  5. [5] Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology
    6. [NORA names: Germany; Europe, EU; OECD]

Abstract

Nonfullerene acceptors (NFAs) have dramatically improved the power conversion efficiency (PCE) of organic photovoltaics (OPV) in recent years; however, their device stability currently remains a bottleneck for further technological progress. Photocatalytic decomposition of nonfullerene acceptor molecules at metal oxide electron transport layer (ETL) interfaces has in several recent reports been demonstrated as one of the main degradation mechanisms for these high-performing OPV devices. While some routes for mitigating such degradation effects have been proposed, e.g., through a second layer integrated on the ETL surface, no clear strategy that complies with device scale-up and application requirements has been presented to date. In this work, it is demonstrated that the development of sputtered titanium oxide layers as ETLs in nonfullerene acceptor based OPV can lead to significantly enhanced device lifetimes. This is achieved by tuning the concentration of defect states at the oxide surface, via the reactive sputtering process, to mitigate the photocatalytic decomposition of NFA molecules at the metal oxide interlayers. Reduced defect state formation at the oxide surface is confirmed through X-ray photoelectron spectroscopy (XPS) studies, while the reduced photocatalytic decomposition of nonfullerene acceptor molecules is confirmed via optical spectroscopy investigations. The PBDB-T:ITIC organic solar cells show power conversion efficiencies of around 10% and significantly enhanced photostability. This is achieved through a reactive sputtering process that is fully scalable and industry compatible.

Keywords

ETL surface, OPV devices, PBDB-T, X-ray, X-ray photoelectron spectroscopy, acceptor, acceptor molecules, application requirements, applications, bottleneck, cells, concentration, concentration of defect states, conversion, conversion efficiency, decomposition, defect state formation, defect states, degradation, degradation effects, degradation mechanism, development, device lifetime, device scale-up, device stability, devices, effect, efficiency, electron transport layer, enhanced photostability, enhanced stability, formation, high-performance OPV devices, industry, interface, interlayer, investigation, layer, lifetime, mechanism, metal, metal oxide electron transport layer, metal oxide interlayers, molecules, nonfullerene, nonfullerene acceptor molecules, nonfullerene acceptors, optical spectroscopy investigations, organic photovoltaics, organic solar cells, oxidation, oxide electron transport layer, oxide interlayer, oxide layer, oxide surface, photocatalytic decomposition, photoelectron spectroscopy, photostability, photovoltaics, power, power conversion efficiency, process, progression, reactive sputtering process, reports, requirements, route, scale-up, solar cells, spectroscopy, spectroscopy investigations, sputtering, sputtering process, stability, stability of organic photovoltaics, state, state formation, surface, surface defect states, technological progress, titanium oxide layer, transport layer, years

Funders

  • Danish Ministry of Higher Education and Science
  • Danish Agency for Science and Higher Education

Data Provider: Digital Science

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