Abstract
Despite the wide use of blends combining an organic p-type polymer and molecular fullerene-based electron acceptor, the proper characterization of such bulk heterojunction materials is still challenging. To highlight structure-to-function relations and improve the device performance, advanced tools and strategies need to be developed to characterize composition and interfaces with sufficient accuracy. In this work, high-resolution X-ray photoelectron spectroscopy (XPS) is combined with very low energy argon ion beam sputtering to perform a nondestructive depth profile chemical analysis on full Al/P3HT:PCBM/PEDOT:PSS/ITO (P3HT, poly(3-hexylthiophene); PCBM, [6,6]-phenyl-C61-butyric acid methyl ester; PEDOT, poly(3,4-ethylenedioxythiophene; PSS, polystyrenesulfonate; ITO, indium tin oxide) bulk-heterojunction solar cell device stacks. Key information, such as P3HT and PCBM composition profiles and Al-PCBM chemical bonding, are deduced in this basic device structure. The interface chemical analysis allows us to evidence, with unprecedented accuracy, the inhomogeneous distribution of PCBM, characterized by a strong segregation toward the top metal electrode. The chemical analysis highresolution spectra allows us to reconstruct P3HT/PCBM ratio through the active layer depth and correlate with the device deposition protocol and performance. Results evidence an inhomogeneous P3HT/PCBM ratio and poorly controllable PCBM migration, which possibly explains the limited light-to-power conversion efficiency in this basic device structure. The work illustrates the high potential of XPS depth profile analysis for studying such organic/inorganic device stacks.
Translated title of the contribution | Analyse chimique des interface dans des cellules solaires à hétérojonction bulk par profilage XPS |
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Original language | English |
Pages (from-to) | 3842-3848 |
Number of pages | 7 |
Journal | ACS Applied Materials & Interfaces |
Volume | 9 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Feb 2017 |
Keywords
- Bulk heterojunction
- Chemical analysis
- Depth profile
- Low-energy ion beams
- P3HT:PCBM
- Solar cells
- XPS
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Synthesis, Irradiation and Analysis of Materials (SIAM)
Pierre Louette (Manager), Julien Colaux (Manager), Alexandre Felten (Manager), Tijani Tabarrant (Operator), Frederic COME (Operator) & Paul-Louis Debarsy (Manager)
Technological Platform Synthesis, Irradiation and Analysis of MaterialsFacility/equipment: Technological Platform