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Sun Y, Xu Z, Wang Y, Niu Z, Xu Z, Li S, Wang W, Liu Y. Enhanced performance of thermally activated delayed fluorescent light emitting diodes by optimized host polarity. OPTICS EXPRESS 2024; 32:17942-17952. [PMID: 38858962 DOI: 10.1364/oe.522090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/17/2024] [Indexed: 06/12/2024]
Abstract
The interaction between the intrinsic polarity of the host material and the TADF guest material affects charge injection and transport, exciton formation, charge recombination, and emission mechanisms. Therefore, understanding and controlling the interaction between the intrinsic polarity of the host material and the TADF guest material is very important to realize efficient TADF-OLED devices. This study investigated the molecular interaction between different polar host materials and a thermally activated delayed fluorescence material (DMAc-PPM). It has been found that interaction between the host and guest (π-π stacking interaction, multiple CH/π contacts) greatly influence the molecular transition dipole moment orientation of the guest. And the OLED devices based on the strong polar host (DPEPO) exhibited the highest EQEmax and lowest luminescence intensity, while devices using the weaker polar hosts mCP and CBP achieved higher luminance and lower EQEmax. Then, the strong polar host DPEPO was mixed with the weaker polar hosts CBP and mCP, respectively. The devices prepared based on the mixed-host DPEPO: mCP showed a 2.2 times improvement in EQEmax from 6.3% to 20.1% compared to the single-host mCP. The devices prepared based on the mixed-host DPEPO: CBP showed a 3.1 times improvement in luminance intensity from 1023 cd/m2 to 4236 cd/m2 compared to the single host of DPEPO. This suggests that optimizing the polarity of host materials has the potential to enhance the performance of solution prepared OLED devices.
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Chen D, Tenopala‐Carmona F, Knöller JA, Mischok A, Hall D, Madayanad Suresh S, Matulaitis T, Olivier Y, Nacke P, Gießelmann F, Laschat S, Gather MC, Zysman‐Colman E. Mesogenic Groups Control the Emitter Orientation in Multi-Resonance TADF Emitter Films. Angew Chem Int Ed Engl 2023; 62:e202218911. [PMID: 36760211 PMCID: PMC10947294 DOI: 10.1002/anie.202218911] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
The use of thermally activated delayed fluorescence (TADF) emitters and emitters that show preferential horizontal orientation of their transition dipole moment (TDM) are two emerging strategies to enhance the efficiency of OLEDs. We present the first example of a liquid crystalline multi-resonance TADF (MR-TADF) emitter, DiKTa-LC. The compound possesses a nematic liquid crystalline phase between 80 °C and 110 °C. Importantly, the TDM of the spin-coated film shows preferential horizontal orientation, with an anisotropy factor, a, of 0.28, which is preserved in doped poly(vinylcarbazole) films. Green-emitting (λEL =492 nm) solution-processed OLEDs based on DiKTa-LC showed an EQEmax of 13.6 %. We thus demonstrate for the first time how self-assembly of a liquid crystalline TADF emitter can lead to the so-far elusive control of the orientation of the transition dipole in solution-processed films, which will be of relevance for high-performance solution-processed OLEDs.
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Affiliation(s)
- Dongyang Chen
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Francisco Tenopala‐Carmona
- Humboldt Centre for Nano- and BiophotonicsDepartment of ChemistryUniversity of CologneGreinstr. 4-650939KölnGermany
| | - Julius A. Knöller
- Institut für Organische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Andreas Mischok
- Humboldt Centre for Nano- and BiophotonicsDepartment of ChemistryUniversity of CologneGreinstr. 4-650939KölnGermany
| | - David Hall
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
- Laboratory for Chemistry of Novel MaterialsUniversity of MonsMonsBelgium
| | - Subeesh Madayanad Suresh
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Tomas Matulaitis
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Yoann Olivier
- Laboratory for Computational Modeling of Functional MaterialsNamur Institute of Structured MatterUniversité de NamurRue de Bruxelles 615000NamurBelgium
| | - Pierre Nacke
- Institut für Physikalische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Frank Gießelmann
- Institut für Physikalische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Sabine Laschat
- Institut für Organische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Malte C. Gather
- Humboldt Centre for Nano- and BiophotonicsDepartment of ChemistryUniversity of CologneGreinstr. 4-650939KölnGermany
| | - Eli Zysman‐Colman
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
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Bracamonte AG. Current Advances in Nanotechnology for the Next Generation of Sequencing (NGS). BIOSENSORS 2023; 13:260. [PMID: 36832027 PMCID: PMC9954403 DOI: 10.3390/bios13020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/03/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
This communication aims at discussing strategies based on developments from nanotechnology focused on the next generation of sequencing (NGS). In this regard, it should be noted that even in the advanced current situation of many techniques and methods accompanied with developments of technology, there are still existing challenges and needs focused on real samples and low concentrations of genomic materials. The approaches discussed/described adopt spectroscopical techniques and new optical setups. PCR bases are introduced to understand the role of non-covalent interactions by discussing about Nobel prizes related to genomic material detection. The review also discusses colorimetric methods, polymeric transducers, fluorescence detection methods, enhanced plasmonic techniques such as metal-enhanced fluorescence (MEF), semiconductors, and developments in metamaterials. In addition, nano-optics, challenges linked to signal transductions, and how the limitations reported in each technique could be overcome are considered in real samples. Accordingly, this study shows developments where optical active nanoplatforms generate signal detection and transduction with enhanced performances and, in many cases, enhanced signaling from single double-stranded deoxyribonucleic acid (DNA) interactions. Future perspectives on miniaturized instrumentation, chips, and devices aimed at detecting genomic material are analyzed. However, the main concept in this report derives from gained insights into nanochemistry and nano-optics. Such concepts could be incorporated into other higher-sized substrates and experimental and optical setups.
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Affiliation(s)
- Angel Guillermo Bracamonte
- Instituto de Investigaciones en Físicoquímica de Córdoba (INFIQC), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina; or
- Departement de Chimie et Centre d’Optique, Photonique et Laser (COPL), Université Laval, Québec, QC G1V 0A6, Canada
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4
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Kim JS, Kwon SH, Kim YS. Probing impact of interface mixing on the charge carrier dynamics of a solution-processed organic light emitting diode via impedance spectroscopy. NANOSCALE 2023; 15:1529-1536. [PMID: 36624999 DOI: 10.1039/d2nr05261j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Recently, several studies have revealed that the thermal annealing process induces intermixing at the interfaces of multilayered solution-processed organic light emitting diodes (OLEDs) and enhances their device performance. Depth profiling measurements, such as neutron reflectometry, have meticulously shown that significant intermixing occurs when the annealing temperature exceeds the glass transition temperature (Tg) of OLED materials. However, electrical characterization to unveil the physical origins of the correlation between interfacial characteristics and device performance is still lacking. Here, we introduce impedance spectroscopy (IS) analysis to examine the thermally induced modifications of charge carrier dynamics in a solution-processed bilayer OLED, consisting of an emission layer and an electron transporting layer (ETL). The characteristic relaxation frequency and capacitance extracted from the capacitance-frequency spectra of the OLEDs thermally annealed at varying temperatures were utilized to separately assess the conductance of the ETL and interfacial carrier accumulation, respectively. The results show that the improved charge transport of the ETL upon thermal annealing is mainly responsible for the performance enhancement since annealing the OLEDs at a temperature above the Tg of the ETL, at which significant intermixing occurs, promotes non-radiative trap-assisted recombination and thereby deteriorates the current efficiency. The proposed IS analysis exhibits that IS can separately probe the charge transport, interfacial charge accumulation and recombination process which are crucial for accurate analysis of charge carrier dynamics in solution-processed OLEDs and can thus be utilized to identify the key factors limiting the device performance.
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Affiliation(s)
- Ji Soo Kim
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
| | - Soon-Hyung Kwon
- Display Research Center, Korea Electronics Technology Institute, 25 Saenari-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13509, Republic of Korea.
| | - Youn Sang Kim
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
- Department of Chemical and Biological Engineering and Institute of Chemical Processes, College of Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea
- Advanced Institutes of Convergence Technology, 145 Gwanggyo-ro, Yeongtong-gu, Suwon, 16229, Republic of Korea
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Crovini E, Zhang Z, Kusakabe Y, Ren Y, Wada Y, Naqvi BA, Sahay P, Matulaitis T, Diesing S, Samuel IDW, Brütting W, Suzuki K, Kaji H, Bräse S, Zysman-Colman E. Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode. Beilstein J Org Chem 2021; 17:2894-2905. [PMID: 34956408 PMCID: PMC8685574 DOI: 10.3762/bjoc.17.197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/19/2021] [Indexed: 12/02/2022] Open
Abstract
In this work we showcase the emitter DICzTRZ in which we employed a twin-emitter design of our previously reported material, ICzTRZ. This new system presented a red-shifted emission at 488 nm compared to that of ICzTRZ at 475 nm and showed a comparable photoluminescence quantum yield of 57.1% in a 20 wt % CzSi film versus 63.3% for ICzTRZ. The emitter was then incorporated within a solution-processed organic light-emitting diode that showed a maximum external quantum efficiency of 8.4%, with Commission Internationale de l'Éclairage coordinate of (0.22, 0.47), at 1 mA cm-2.
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Affiliation(s)
- Ettore Crovini
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Zhen Zhang
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Yu Kusakabe
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yongxia Ren
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yoshimasa Wada
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Bilal A Naqvi
- Experimental Physics IV, Institute of Physics, University of Augsburg, Universitätstrasse. 1, 86159 Augsburg, Germany
| | - Prakhar Sahay
- Experimental Physics IV, Institute of Physics, University of Augsburg, Universitätstrasse. 1, 86159 Augsburg, Germany
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Stefan Diesing
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
| | - Wolfgang Brütting
- Experimental Physics IV, Institute of Physics, University of Augsburg, Universitätstrasse. 1, 86159 Augsburg, Germany
| | - Katsuaki Suzuki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Stefan Bräse
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
- Institute of Biological and Chemical Systems – Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
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Akman E, Akin S. Poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine-Based Interfacial Passivation Strategy Promoting Efficiency and Operational Stability of Perovskite Solar Cells in Regular Architecture. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006087. [PMID: 33289215 DOI: 10.1002/adma.202006087] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/15/2020] [Indexed: 06/12/2023]
Abstract
The failure of perovskite solar cells (PSCs) to maintain their maximum efficiency over a prolonged time is due to the deterioration of the light harvesting material under environmental factors such as humidity, heat, and light. Systematically elucidating and eliminating such degradation pathways are critical to imminent commercial use of this technology. Here, a straightforward approach is introduced to reduce the level of defect-states present at the perovskite and hole transporting layer interface by treating the various perovskite surfaces with poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine (polyTPD) molecules. This strategy significantly suppresses the defect-mediated non-radiative recombination in the ensuing devices and prevents the penetration of degrading agents into the inner layers by passivating the perovskite surface and grain boundaries. Suppressed non-radiative recombination and improved interfacial hole extraction result in PSCs with stabilized efficiency exceeding 21% with negligible hysteresis (≈19.1% for control device). Moreover, ultra-hydrophobic polyTPD passivant considerably alleviates moisture penetration, showing ≈91% retention of initial efficiencies after 300 h storage at high relative humidity of 80%. Similarly, passivated device retains 94% of its initial efficiency after 800 h under operational conditions (maximum power point tracking under continuous illumination at 60 °C). In addition to interfacial passivation function, hole-selective role of dopant-free polyTPD is also evaluated and discussed in this study.
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Affiliation(s)
- Erdi Akman
- Scientific and Technological Research and Application Center, Karamanoglu Mehmetbey University, Karaman, 70200, Turkey
| | - Seckin Akin
- Department of Metallurgical and Materials Engineering, Karamanoglu Mehmetbey University, Karaman, 70200, Turkey
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Boehm BJ, Nguyen HTL, Huang DM. The interplay of interfaces, supramolecular assembly, and electronics in organic semiconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:423001. [PMID: 31212263 DOI: 10.1088/1361-648x/ab2ac2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Organic semiconductors, which include a diverse range of carbon-based small molecules and polymers with interesting optoelectronic properties, offer many advantages over conventional inorganic semiconductors such as silicon and are growing in importance in electronic applications. Although these materials are now the basis of a lucrative industry in electronic displays, many promising applications such as photovoltaics remain largely untapped. One major impediment to more rapid development and widespread adoption of organic semiconductor technologies is that device performance is not easily predicted from the chemical structure of the constituent molecules. Fundamentally, this is because organic semiconductor molecules, unlike inorganic materials, interact by weak non-covalent forces, resulting in significant structural disorder that can strongly impact electronic properties. Nevertheless, directional forces between generally anisotropic organic-semiconductor molecules, combined with translational symmetry breaking at interfaces, can be exploited to control supramolecular order and consequent electronic properties in these materials. This review surveys recent advances in understanding of supramolecular assembly at organic-semiconductor interfaces and its impact on device properties in a number of applications, including transistors, light-emitting diodes, and photovoltaics. Recent progress and challenges in computer simulations of supramolecular assembly and orientational anisotropy at these interfaces is also addressed.
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Affiliation(s)
- Belinda J Boehm
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, SA 5005, Australia
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8
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Affiliation(s)
- Tommaso Marcato
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied BiosciencesETH Zürich Vladimir-Prelog-Weg 1–5/10 CH-8093 Zürich Switzerland
| | - Chih‐Jen Shih
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied BiosciencesETH Zürich Vladimir-Prelog-Weg 1–5/10 CH-8093 Zürich Switzerland
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9
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Huckaba AJ, Senes A, Aghazada S, Babaei A, Meskers SCJ, Zimmermann I, Schouwink P, Gasilova N, Janssen RAJ, Bolink HJ, Nazeeruddin MK. Bis(arylimidazole) Iridium Picolinate Emitters and Preferential Dipole Orientation in Films. ACS OMEGA 2018; 3:2673-2682. [PMID: 29623303 PMCID: PMC5879467 DOI: 10.1021/acsomega.8b00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
The straightforward synthesis and photophysical properties of a new series of heteroleptic iridium(III) bis(2-arylimidazole) picolinate complexes are reported. Each complex has been characterized by nuclear magnetic resonance, UV-vis, cyclic voltammetry, and photoluminescent angle dependency, and the emissive properties of each are described. The preferred orientation of transition dipoles in emitter/host thin films indicated more preferred orientation than homoleptic complex Ir(ppy)3.
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Affiliation(s)
- Aron J. Huckaba
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
| | - Alessia Senes
- Holst
Centre/TNO, High Tech
Campus 31, P.O. Box 8550, 5605 KN Eindhoven, The Netherlands
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Sadig Aghazada
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
| | - Azin Babaei
- Instituto
de Ciencia Molecular, Universidad de Valencia, c/Catedrático J. Beltrán
2, 46980 Paterna, Spain
| | - Stefan C. J. Meskers
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Iwan Zimmermann
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
| | - Pascal Schouwink
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
| | - Natalia Gasilova
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
| | - René A. J. Janssen
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Henk J. Bolink
- Instituto
de Ciencia Molecular, Universidad de Valencia, c/Catedrático J. Beltrán
2, 46980 Paterna, Spain
| | - Mohammad Khaja Nazeeruddin
- Group
for Molecular Engineering of Functional Materials, Institute
of Chemical Sciences and Engineering, and Institute of Chemical Sciences
and Engineering, Ecole Polytechnique Federale
de Lausanne Valais Wallis, Rue de l’Indutrie 17, 1950 Sion, Valais, Switzerland
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Komino T, Kuwae H, Okada A, Fu W, Mizuno J, Ribierre JC, Oki Y, Adachi C. In-Plane Anisotropic Molecular Orientation of Pentafluorene and Its Application to Linearly Polarized Electroluminescence. ACS APPLIED MATERIALS & INTERFACES 2017; 9:27054-27061. [PMID: 28771326 DOI: 10.1021/acsami.7b05570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
By preparing parallelly aligned 1.9-μm-high SiO2 microfluidic channels on an indium tin oxide substrate surface, the solution flow direction during spin-coating was controlled to be parallel to the grating. Using this technique, a pentafluorene-4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) binary solution in chloroform was spin-coated to embed a 40-50 nm-thick 10 wt %-pentafluorene:CBP thin film in the channels. In-plane polarized photoluminescence measurements revealed that the pentafluorene molecules tended to orient along the grating, demonstrating that one-dimensional fluid flow can control the in-plane molecular orientation. Furthermore, the dependences of the photoluminescence anisotropy on the spin speed and substrate material suggest that the velocity of the solution flow and/or its gradient in the vertical direction greatly affects the resulting orientation. This indicates that the mechanism behind the molecular orientation is related to stress such as the shear force. The effect of the solution flow on the molecular orientation was demonstrated even in organic light-emitting diodes (OLEDs). Linearly polarized electroluminescence was obtained by applying the in-plane orientation to OLEDs, and it was found that the dichroic ratio of the electroluminescence orthogonal (x) and parallel (y) to the grating is x/y = 0.75.
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Affiliation(s)
- Takeshi Komino
- Education Center for Global Leaders in Molecular System for Devices, Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- ERATO, Adachi Molecular Exciton Engineering Project, Japan Science and Technology Agency , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Hiroyuki Kuwae
- ERATO, Adachi Molecular Exciton Engineering Project, Japan Science and Technology Agency , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Nano-Science and Nano-Engineering, Waseda University , 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Akiko Okada
- Nano-Science and Nano-Engineering, Waseda University , 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Weixin Fu
- Nano-Science and Nano-Engineering, Waseda University , 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Jun Mizuno
- Organization for Nano and Life Innovation, Waseda University , 513 Waseda Tsurumaki-cho, Shinjuku, Tokyo 162-0041, Japan
| | - Jean-Charles Ribierre
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- ERATO, Adachi Molecular Exciton Engineering Project, Japan Science and Technology Agency , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Yuji Oki
- ERATO, Adachi Molecular Exciton Engineering Project, Japan Science and Technology Agency , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Department of Electronics, Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Chihaya Adachi
- Education Center for Global Leaders in Molecular System for Devices, Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- ERATO, Adachi Molecular Exciton Engineering Project, Japan Science and Technology Agency , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University , 744 Motooka, Nishi, Fukuoka 819-0395, Japan
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