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Mei H, Laws TS, Terlier T, Verduzco R, Stein GE. Characterization of polymeric surfaces and interfaces using
time‐of‐flight
secondary ion mass spectrometry. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hao Mei
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
| | - Travis S. Laws
- Department of Chemical and Biomolecular Engineering University of Tennessee Knoxville Tennessee USA
| | - Tanguy Terlier
- Shared Equipment Authority Rice University Houston Texas USA
| | - Rafael Verduzco
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
- Shared Equipment Authority Rice University Houston Texas USA
- Materials Science and NanoEngineering Rice University Houston Texas USA
| | - Gila E. Stein
- Department of Chemical and Biomolecular Engineering University of Tennessee Knoxville Tennessee USA
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2
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Ben Hadj Mabrouk A, Licitra C, Chateauminois A, Veillerot M. Effect of the molecular weight on the depth profiling of PMMA thin films using low‐energy Cs
+
sputtering. SURF INTERFACE ANAL 2021. [DOI: 10.1002/sia.6991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | | | - Antoine Chateauminois
- Soft Matter Science and Engineering Laboratory (SIMM) PSL Research University, UPMC Univ. Paris 06, Sorbonne Universités, ESPCI Paris, CNRS 75231 Paris Cedex 05 France
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3
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Wang SK, Chang HY, Chu YH, Kao WL, Wu CY, Lee YW, You YW, Chu KJ, Hung SH, Shyue JJ. Effect of energy per atom (E/n) on the Ar gas cluster ion beam (Ar-GCIB) and O 2+ cosputter process. Analyst 2019; 144:3323-3333. [PMID: 30968864 DOI: 10.1039/c8an02452a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gas cluster ion beam (GCIB) is a promising technique for preserving molecular structures during ion sputtering and successfully profiling biological and soft materials. However, although GCIB yields lower damage accumulation compared with C60+ and monoatomic ion beams, the inevitable alteration of the chemical structure can introduce artifacts into the resulting depth profile. To enhance the ionization yield and further mask damage, a low-energy O2+ (200-500 V) cosputter can be applied. While the energy per atom (E/n) of GCIB is known to be an important factor influencing the sputter process, the manner through which E/n affects the GCIB-O2+ cosputter process remains unclear. In this study, poly(ethylene terephthalate) (PET) was used as a model material to investigate the sputter process of 10-20 kV Ar1000-4000+ (E/n = 2.5-20 eV per atom) with and without O2+ cosputter at different energies and currents. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) with Bi32+ as the primary ion was used to examine surfaces sputtered at different fluences. The sputter craters were also measured by alpha-step and atomic force microscopy in quantitative imaging mode. The SIMS results showed that the steady-state cannot be obtained with E/n values of less than 5 eV per atom due to damage accumulation using single GCIB sputtering. With a moderate E/n value of 5-15 eV per atom, the steady-state can be obtained, but the ∼50% decay in intensity indicated that damage cannot be masked completely despite the higher sputter yield. Furthermore, the surface Young's modulus decreased with increasing E/n, suggesting that depolymerization occurred. At an E/n value of 20 eV per atom, a failed profile was obtained with rapidly decreased sputter rate and secondary ion intensity due to the ion-induced crosslink. With O2+ cosputtering and a moderate E/n value, the oxidized species generated by O2+ enhanced the ionization yield, which led to a higher ion intensity at steady-state in general. Because higher kinetic energy or current density of O2+ led to a larger interaction volume and more structural damage that suppressed molecular ion intensity, the enhancement from O2+ was most apparent with low-energy-high-current (200 V, 80 μA cm-2) or high-energy-low-current (500 V, 5 μA cm-2) O2+ cosputtering with 0.5 μA cm-2 GCIBs. In these cases, little or no intensity drop was observed at the steady-state.
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Affiliation(s)
- Shin-Kung Wang
- Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
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4
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Noël C, Pescetelli S, Agresti A, Franquet A, Spampinato V, Felten A, di Carlo A, Houssiau L, Busby Y. Hybrid Perovskites Depth Profiling with Variable-Size Argon Clusters and Monatomic Ions Beams. MATERIALS 2019; 12:ma12050726. [PMID: 30832309 PMCID: PMC6427474 DOI: 10.3390/ma12050726] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 02/15/2019] [Accepted: 02/27/2019] [Indexed: 11/16/2022]
Abstract
Ion beam depth profiling is increasingly used to investigate layers and interfaces in complex multilayered devices, including solar cells. This approach is particularly challenging on hybrid perovskite layers and perovskite solar cells because of the presence of organic/inorganic interfaces requiring the fine optimization of the sputtering beam conditions. The ion beam sputtering must ensure a viable sputtering rate on hard inorganic materials while limiting the chemical (fragmentation), compositional (preferential sputtering) or topographical (roughening and intermixing) modifications on soft organic layers. In this work, model (Csx(MA0.17FA0.83)100−xPb(I0.83Br0.17)3/cTiO2/Glass) samples and full mesoscopic perovskite solar cells are profiled using low-energy (500 and 1000 eV) monatomic beams (Ar+ and Cs+) and variable-size argon clusters (Arn+, 75 < n < 4000) with energy up to 20 keV. The ion beam conditions are optimized by systematically comparing the sputtering rates and the surface modifications associated with each sputtering beam. X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and in-situ scanning probe microscopy are combined to characterize the interfaces and evidence sputtering-related artifacts. Within monatomic beams, 500 eV Cs+ results in the most intense and stable ToF-SIMS molecular profiles, almost material-independent sputtering rates and sharp interfaces. Large argon clusters (n > 500) with insufficient energy (E < 10 keV) result in the preferential sputtering of organic molecules and are highly ineffective to sputter small metal clusters (Pb and Au), which tend to artificially accumulate during the depth profile. This is not the case for the optimized cluster ions having a few hundred argon atoms (300 < n < 500) and an energy-per-atom value of at least 20 eV. In these conditions, we obtain (i) the low fragmentation of organic molecules, (ii) convenient erosion rates on soft and hard layers (but still different), and (iii) constant molecular profiles in the perovskite layer, i.e., no accumulation of damages.
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Affiliation(s)
- Céline Noël
- Laboratoire Interdisciplinaire de Spectroscopie Electronique, Namur Institute of Structured Matter, University of Namur, 5000 Namur, Belgium.
| | - Sara Pescetelli
- C.H.O.S.E.-Centre for Hybrid and Organic Solar Energy, Department of Electronic Engineering, University of Rome Tor Vergata, 00133 Rome, Italy.
| | - Antonio Agresti
- C.H.O.S.E.-Centre for Hybrid and Organic Solar Energy, Department of Electronic Engineering, University of Rome Tor Vergata, 00133 Rome, Italy.
| | | | | | | | - Aldo di Carlo
- C.H.O.S.E.-Centre for Hybrid and Organic Solar Energy, Department of Electronic Engineering, University of Rome Tor Vergata, 00133 Rome, Italy.
| | - Laurent Houssiau
- Laboratoire Interdisciplinaire de Spectroscopie Electronique, Namur Institute of Structured Matter, University of Namur, 5000 Namur, Belgium.
| | - Yan Busby
- Laboratoire Interdisciplinaire de Spectroscopie Electronique, Namur Institute of Structured Matter, University of Namur, 5000 Namur, Belgium.
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5
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Havelund R, Seah MP, Tiddia M, Gilmore IS. SIMS of Organic Materials-Interface Location in Argon Gas Cluster Depth Profiles Using Negative Secondary Ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:774-785. [PMID: 29468500 PMCID: PMC5889422 DOI: 10.1007/s13361-018-1905-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 06/08/2023]
Abstract
A procedure has been established to define the interface position in depth profiles accurately when using secondary ion mass spectrometry and the negative secondary ions. The interface position varies strongly with the extent of the matrix effect and so depends on the secondary ion measured. Intensity profiles have been measured at both fluorenylmethyloxycarbonyl-L-pentafluorophenylalanine (FMOC) to Irganox 1010 and Irganox 1010 to FMOC interfaces for many secondary ions. These profiles show separations of the two interfaces that vary over some 10 nm depending on the secondary ion selected. The shapes of these profiles are strongly governed by matrix effects, slightly weakened by a long wavelength roughening. The matrix effects are separately measured using homogeneous, known mixtures of these two materials. Removal of the matrix and roughening effects give consistent compositional profiles for all ions that are described by an integrated exponentially modified Gaussian (EMG) profile. Use of a simple integrated Gaussian may lead to significant errors. The average interface positions in the compositional profiles are determined to standard uncertainties of 0.19 and 0.14 nm, respectively, using the integrated EMG function. Alternatively, and more simply, it is shown that interface positions and profiles may be deduced from data for several secondary ions with measured matrix factors by simply extrapolating the result to Ξ = 0. Care must be taken in quoting interface resolutions since those measured for predominantly Gaussian interfaces with Ξ above or below zero, without correction, appear significantly better than the true resolution. Graphical Abstract ᅟ.
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Affiliation(s)
- R Havelund
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK.
| | - M P Seah
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
| | - M Tiddia
- Universita degli Studi di Cagliari, Dipartimento di Fisica S. P. Monserrato, Sestu Km 0.700, 09042, Monserrato, CA, Italy
| | - I S Gilmore
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
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6
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Nakano K, Shibamori T, Tajima K. Quantitative Evaluation of Molecular Diffusion in Organic Planar Heterojunctions by Time-of-Flight Secondary Ion Mass Spectroscopy. ACS OMEGA 2018; 3:1522-1528. [PMID: 31458477 PMCID: PMC6641331 DOI: 10.1021/acsomega.7b01524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/22/2017] [Indexed: 06/08/2023]
Abstract
Understanding molecular diffusion across the interfaces in planar heterojunctions is fundamentally important to improving the performance and stability of organic electronic devices. In this study, we quantitatively evaluated the diffusion of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) across the interface of planar heterojunctions into the polymer layers by time-of-flight secondary ion mass spectroscopy. Careful calibration allowed the concentration of PCBM to be determined in the polymer layer at concentrations as low as 0.01 wt %. We found that approximately 1 wt % PCBM was present in the poly(3-hexylthiophene) layer in the planar heterojunction with no thermal treatments, indicating that a small amount of PCBM diffused into the polymer layer even at room temperature. The diffusion behavior depended strongly on the crystallinity of the PCBM layer and the properties of the polymer layers such as glass transition temperature. Further analysis suggested that the diffusion of PCBM into the polymer layers was also related to the interface free energy between the layers.
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Affiliation(s)
- Kyohei Nakano
- RIKEN
Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takahiro Shibamori
- TORAY
Research Center, Inc., 3-3-7, Sonoyama, Otsu, Shiga 520-8567, Japan
| | - Keisuke Tajima
- RIKEN
Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Precursory
Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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7
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Chintala R, Tait JG, Eyben P, Voroshazi E, Surana S, Fleischmann C, Conard T, Vandervorst W. Insights into the nanoscale lateral and vertical phase separation in organic bulk heterojunctions via scanning probe microscopy. NANOSCALE 2016; 8:3629-3637. [PMID: 26810305 DOI: 10.1039/c5nr08765a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Solution processed polymer (donor) and fullerene (acceptor) bulk heterojunctions are widely used as the photo active layer in organic solar cells. Intimate mixing of these two materials is essential for efficient charge separation and transport. Identifying relative positions of acceptor and donor rich regions in the bulk heterojunction with nanometer scale precision is crucial in understanding intricate details of operation. In this work, a combination of Ar(+)2000 gas cluster ion beam and scanning probe microscopy is used to examine the lateral and vertical phase separation within regio-regular poly(3-hexylthiophene)(P3HT):phenyl-C60-butyric acid methyl ester (PCBM) bulk heterojunction. While the Ar(+)2000 gas cluster ion beam is used as a sputter tool to expose the underneath layers, scanning probe microscopy techniques are used to obtain two-dimensional (2D) electrical maps (with sub-2 nm lateral resolution). The electrical mapping is decoded to chemical composition, essentially producing lateral and vertical maps of phase separation. Thermal stress causes large PCBM-rich hillocks to form, and consequently affecting the balance of P3HT:PCBM heterojunctions, hence a negative impact on the efficiency of the solar cell. We further developed a method to analyze the efficiency of exciton dissociation based on the current maps and a loss of 20% in efficiency is observed for thermally degraded samples compared to fresh un-annealed samples.
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Affiliation(s)
- R Chintala
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium. and Instituut voor Kern-en Stralingsfysica, (IKS), Celestijnenlaan 200D, B-3001 Leuven, Belgium
| | - J G Tait
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium. and KU Leuven, ESAT, Kasteelpark Arenberg 10, B-3001, Leuven, Belgium
| | - P Eyben
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium.
| | - E Voroshazi
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium.
| | - S Surana
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium. and Instituut voor Kern-en Stralingsfysica, (IKS), Celestijnenlaan 200D, B-3001 Leuven, Belgium
| | | | - T Conard
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium.
| | - W Vandervorst
- IMEC, Kapeldreef 75, B-3001, Leuven, Belgium. and Instituut voor Kern-en Stralingsfysica, (IKS), Celestijnenlaan 200D, B-3001 Leuven, Belgium
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8
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Seah MP, Havelund R, Shard AG, Gilmore IS. Sputtering Yields for Mixtures of Organic Materials Using Argon Gas Cluster Ions. J Phys Chem B 2015; 119:13433-9. [DOI: 10.1021/acs.jpcb.5b06713] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- M. P. Seah
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - R. Havelund
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - A. G. Shard
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - I. S. Gilmore
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
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