Tin Oxide Electron Transport Layers for Air-/Solution-Processed Conventional Organic Solar Cells

Anderson Hoff; Mahmoud E Farahat; Majid Pahlevani; Gregory C Welch

doi:10.1021/acsami.1c19790

Tin Oxide Electron Transport Layers for Air-/Solution-Processed Conventional Organic Solar Cells

ACS Appl Mater Interfaces. 2022 Jan 12;14(1):1568-1577. doi: 10.1021/acsami.1c19790. Epub 2022 Jan 3.

Authors

Anderson Hoff^{1

2}, Mahmoud E Farahat^{1

2}, Majid Pahlevani^{1

2}, Gregory C Welch^{1

2}

Affiliations

¹ Department of Chemistry, University of Calgary, 2500 University Drive Northwest, Calgary, AlbertaT2N 1N4, Canada.
² Department of Electrical and Computer Engineering, Queen's University, 19 Union Street, Kingston, OntarioK7L 3N6, Canada.

PMID: 34978404
DOI: 10.1021/acsami.1c19790

Abstract

Commercialization of organic solar cells (OSC) is imminent. Interlayers between the photoactive film and the electrodes are critical for high device efficiency and stability. Here, the applicability of SnO₂ nanoparticles (SnO₂ NPs) as the electron transport layer (ETL) in conventional OSCs is evaluated. A commercial SnO₂ NPs solution in butanol is mixed with ethanol (EtOH) as a processing co-solvent to improve film formation for spin and slot-die coating deposition procedures. When processed with 200% v/v EtOH, the SnO₂ NPs film presents uniform film quality and low photoactive layer degradation. The optimized SnO₂ NPs ink is coated, in air, on top of two polymer:fullerene-based systems and a nonfullerene system, to form an efficient ETL film. In every case, addition of SnO₂ NPs film significantly enhances photovoltaic performance, from 3.4 and 3.7% without the ETL to 6.0 and 5.7% when coated on top of PBDB-T:PC₆₁BM and PPDT2FBT:PC₆₁BM, respectively, and from 3.7 to 7.1% when applied on top of the PTQ10:IDIC system. Flexible, all slot-die-coated devices, in air, are also fabricated and tested, demonstrating the versatility of the SnO₂ NPs ink for efficient ETL formation on top of organic photoactive layers, processed under ambient condition, ideal for practical large-scale production of OSCs.

Keywords: electron transport layer; fullerene and nonfullerene active layers; organic solar cells; slot-die coating; tin oxide.