1
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Le Brun AP, Gilbert EP. Advances in sample environments for neutron scattering for colloid and interface science. Adv Colloid Interface Sci 2024; 327:103141. [PMID: 38631095 DOI: 10.1016/j.cis.2024.103141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/19/2024]
Abstract
This review describes recent advances in sample environments across the full complement of applicable neutron scattering techniques to colloid and interface science. Temperature, pressure, flow, tensile testing, ultrasound, chemical reactions, IR/visible/UV light, confinement, humidity and electric and magnetic field application, as well as tandem X-ray methods, are all addressed. Consideration for material choices in sample environments and data acquisition methods are also covered as well as discussion of current and potential future use of machine learning and artificial intelligence.
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Affiliation(s)
- Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Elliot Paul Gilbert
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia.
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2
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Ferron T, Fiori ME, Ediger MD, DeLongchamp DM, Sunday DF. Composition Dictates Molecular Orientation at the Heterointerfaces of Vapor-Deposited Glasses. JACS AU 2023; 3:1931-1938. [PMID: 37502150 PMCID: PMC10369407 DOI: 10.1021/jacsau.3c00168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/22/2023] [Accepted: 06/09/2023] [Indexed: 07/29/2023]
Abstract
Physical vapor deposition (PVD) can prepare organic glasses with a preferred molecular orientation. The relationships between deposition conditions and orientation have been extensively investigated in the film bulk. The role of interfaces on the structure is less well understood and remains a key knowledge gap, as the interfacial region can govern glass stability and optoelectronic properties. Robust experimental characterization has remained elusive due to complexities in interrogating molecular organization in amorphous, organic materials. Polarized soft X-rays are sensitive to both the composition and the orientation of transition dipole moments in the film, making them uniquely suited to probe molecular orientation in amorphous soft matter. Here, we utilize polarized resonant soft X-ray reflectivity (P-RSoXR) to simultaneously depth profile the composition and molecular orientation of a bilayer prepared through the physical vapor deposition of 1,4-di-[4-(N,N-diphenyl)amino]styryl-benzene (DSA-Ph) on a film of aluminum-tris(8-hydroxyquinoline) (Alq3). The bulk orientation of the DSA-Ph layer is controlled by varying deposition conditions. Utilizing P-RSoXR to depth profile the films enables determination of both the bulk orientation of DSA-Ph and the orientation near the Alq3 interface. At the Alq3 surface, DSA-Ph always lies with its long axis parallel to the interface, before transitioning into the bulk orientation. This is likely due to the lower mobility and higher glass transition of Alq3, as the first several monolayers of DSA-Ph deposited on Alq3 appear to behave as a blend. We further show how orientation at the interface correlates with the bulk behavior of a codeposited glass of similar blend composition, demonstrating a straightforward approach to predicting molecular orientation at heterointerfaces. This work provides key insights into how molecules orient during vapor deposition and offers methods to predict this property, a critical step toward controlling interfacial behavior in soft matter.
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Affiliation(s)
- Thomas
J. Ferron
- National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Marie E. Fiori
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - M. D. Ediger
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Dean M. DeLongchamp
- National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Daniel F. Sunday
- National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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3
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Xu H, Cao C, Shui X, Gu J, Sun Y, Ding L, Lin Y, Shi W, Wei B. Discrimination and control of the exciton-recombination region of thermal-stressed blue organic light-emitting diodes. Phys Chem Chem Phys 2023; 25:2742-2746. [PMID: 36644939 DOI: 10.1039/d2cp05600c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Organic light-emitting diodes (OLEDs) suffer from carrier imbalance under high temperatures. We improved their thermal stability by using space interlayers adjacent to the charge transport layers. The current efficiency of the optimized OLEDs increased under high temperature, with an increase of over one order of magnitude of the electron mobility.
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Affiliation(s)
- Hanfei Xu
- School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China
| | - Chenhui Cao
- Anhui Sholon New Material Technology Co., Ltd., Chuzhou, Anhui Province, 239500, China
| | - Xinfeng Shui
- Anhui Sholon New Material Technology Co., Ltd., Chuzhou, Anhui Province, 239500, China
| | - Jialu Gu
- Key Laboratory of Advanced Display and System Applications, Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China.
| | - Yanqiu Sun
- School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou, 215009, China.
| | - Lei Ding
- School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou, 215009, China.
| | - Yang Lin
- Key Laboratory of Advanced Display and System Applications, Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China.
| | - Wei Shi
- Key Laboratory of Advanced Display and System Applications, Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China.
| | - Bin Wei
- Key Laboratory of Advanced Display and System Applications, Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China.
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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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5
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Ferron TJ, Thelen JL, Bagchi K, Deng C, Gann E, de Pablo JJ, Ediger MD, Sunday DF, DeLongchamp DM. Characterization of the Interfacial Orientation and Molecular Conformation in a Glass-Forming Organic Semiconductor. ACS APPLIED MATERIALS & INTERFACES 2022; 14:3455-3466. [PMID: 34982543 DOI: 10.1021/acsami.1c19948] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The ability to control structure in molecular glasses has enabled them to play a key role in modern technology; in particular, they are ubiquitous in organic light-emitting diodes. While the interplay between bulk structure and optoelectronic properties has been extensively investigated, few studies have examined molecular orientation near buried interfaces despite its critical role in emergent functionality. Direct, quantitative measurements of buried molecular orientation are inherently challenging, and many methods are insensitive to orientation in amorphous soft matter or lack the necessary spatial resolution. To overcome these challenges, we use polarized resonant soft X-ray reflectivity (p-RSoXR) to measure nanometer-resolved, molecular orientation depth profiles of vapor-deposited thin films of an organic semiconductor Tris(4-carbazoyl-9-ylphenyl)amine (TCTA). Our depth profiling approach characterizes the vertical distribution of molecular orientation and reveals that molecules near the inorganic substrate and free surface have a different, nearly isotropic orientation compared to those of the anisotropic bulk. Comparison of p-RSoXR results with near-edge X-ray absorption fine structure spectroscopy and optical spectroscopies reveals that TCTA molecules away from the interfaces are predominantly planar, which may contribute to their attractive charge transport qualities. Buried interfaces are further investigated in a TCTA bilayer (each layer deposited under separate conditions resulting in different orientations) in which we find a narrow interface between orientationally distinct layers extending across ≈1 nm. Coupling this result with molecular dynamics simulations provides additional insight into the formation of interfacial structure. This study characterizes the local molecular orientation at various types of buried interfaces in vapor-deposited glasses and provides a foundation for future studies to develop critical structure-function relationships.
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Affiliation(s)
- Thomas J Ferron
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jacob L Thelen
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Kushal Bagchi
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Chuting Deng
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Eliot Gann
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Daniel F Sunday
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Dean M DeLongchamp
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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6
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McEwan JA, Clulow AJ, Nelson A, Krause-Heuer AM, Jansen-van Vuuren RD, Burn PL, Gentle IR. Diffusion in Organic Film Stacks Containing Solution-Processed Phosphorescent Poly(dendrimer) Dopants. ACS APPLIED MATERIALS & INTERFACES 2021; 13:30910-30920. [PMID: 34170676 DOI: 10.1021/acsami.1c05940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Efficient organic light-emitting diodes (OLEDs) consist of an emissive layer comprising a blend of a light-emitting and host material in contact with one or more charge transporting layers. The distribution of the active material in the guest-host emissive layer blend and the changes that may occur upon thermal annealing are two important factors in determining the stability and efficiency of OLEDs. We have combined neutron reflectometry and photoluminescence measurements to investigate the structures of films comprising an emissive layer containing a phosphorescent poly(dendrimer) material blended with 4,4'-N,N'-di(carbazolyl)biphenyl. This combination has been shown to give rise to highly efficient OLEDs. Here, we show that the emissive poly(dendrimer) material was not uniformly distributed in the host, but formed a concentration gradient within the emissive layer. Upon heating, the adjacent electron transport layer was found to intermix with the emissive layer, accompanied by changes in the material distribution in the emissive layer. The intermixing of the materials led to a decrease in the photoluminescence from the poly(dendrimer) within the film. The decrease in the photoluminescence was ascribed to an increase in interchromophore interactions that could arise from a conformational change of the poly(dendrimer) or phase separation leading to aggregation. The results indicate that, while uniform mixing of the guest and host is not essential for efficiency, the thermal stabilities of both host and charge transport materials are important for device durability.
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Affiliation(s)
- Jake A McEwan
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Andrew J Clulow
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Andrew Nelson
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Anwen M Krause-Heuer
- National Deuteration Facility Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Ross D Jansen-van Vuuren
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul L Burn
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ian R Gentle
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
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7
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Kotowicz S, Korzec M, Pająk AK, Golba S, Małecki JG, Siwy M, Grzelak J, Maćkowski S, Schab-Balcerzak E. New Acceptor-Donor-Acceptor Systems Based on Bis-(Imino-1,8-Naphthalimide). MATERIALS 2021; 14:ma14112714. [PMID: 34064056 PMCID: PMC8196752 DOI: 10.3390/ma14112714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/01/2023]
Abstract
In this paper, six novel symmetrical bis-(imino-1,8-naphthalimides) differing in core and N-substituent structure were synthesized, and their thermal (TGA, DSC), optical (UV-Vis, PL), electrochemical (DPV, CV) properties were evaluated. The compounds were stable to 280 °C and could be transferred into amorphous materials. Electrochemical investigations showed their ability to occur reductions and oxidations processes. They exhibited deep LUMO levels of about -3.22 eV and HOMO levels above -5.80 eV. The optical investigations were carried out in the solutions (polar and non-polar) and in films and blends with PVK:PBD. Bis-(imino-1,8-naphthalimides) absorbed electromagnetic radiation in the range of 243-415 nm and emitted light from blue to yellow. Their capacity for light emission under voltage was preliminarily tested in devices with an active layer consisting of a neat compound and a blend with PVK:PBD. The diodes emitted green or red light.
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Affiliation(s)
- Sonia Kotowicz
- Institute of Chemistry, University of Silesia, 9 Szkolna Str., 40-006 Katowice, Poland; (A.K.P.); (J.G.M.); (E.S.-B.)
- Correspondence: (S.K.); (M.K.)
| | - Mateusz Korzec
- Institute of Chemistry, University of Silesia, 9 Szkolna Str., 40-006 Katowice, Poland; (A.K.P.); (J.G.M.); (E.S.-B.)
- Correspondence: (S.K.); (M.K.)
| | - Agnieszka Katarzyna Pająk
- Institute of Chemistry, University of Silesia, 9 Szkolna Str., 40-006 Katowice, Poland; (A.K.P.); (J.G.M.); (E.S.-B.)
| | - Sylwia Golba
- Institute of Materials Engineering, University of Silesia, 75 Pulku Piechoty Str., 41-500 Chorzow, Poland;
| | - Jan Grzegorz Małecki
- Institute of Chemistry, University of Silesia, 9 Szkolna Str., 40-006 Katowice, Poland; (A.K.P.); (J.G.M.); (E.S.-B.)
| | - Mariola Siwy
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Str., 41-819 Zabrze, Poland;
| | - Justyna Grzelak
- Faculty of Physics, Institute of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 5 Grudziadzka Str., 87-100 Torun, Poland; (J.G.); (S.M.)
| | - Sebastian Maćkowski
- Faculty of Physics, Institute of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 5 Grudziadzka Str., 87-100 Torun, Poland; (J.G.); (S.M.)
| | - Ewa Schab-Balcerzak
- Institute of Chemistry, University of Silesia, 9 Szkolna Str., 40-006 Katowice, Poland; (A.K.P.); (J.G.M.); (E.S.-B.)
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Str., 41-819 Zabrze, Poland;
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8
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Bagchi K, Ediger MD. Controlling Structure and Properties of Vapor-Deposited Glasses of Organic Semiconductors: Recent Advances and Challenges. J Phys Chem Lett 2020; 11:6935-6945. [PMID: 32787194 DOI: 10.1021/acs.jpclett.0c01682] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The past decade has seen great progress in manipulating the structure of vapor-deposited glasses of organic semiconductors. Upon varying the substrate temperature during deposition, glasses with a wide range of density and molecular orientation can be prepared from a given molecule. We review recent studies that show the structure of vapor-deposited glasses can be tuned to significantly improve the external quantum efficiency and lifetime of organic light-emitting diodes (OLEDs). We highlight the ability of molecular simulations to reproduce experimentally observed structures, setting the stage for in silico design of vapor-deposited glasses in the coming decade. Finally, we identify research opportunities for improving the properties of organic semiconductors by controlling the structure of vapor-deposited glasses.
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Affiliation(s)
- Kushal Bagchi
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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9
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Liu B, Altintas Y, Wang L, Shendre S, Sharma M, Sun H, Mutlugun E, Demir HV. Record High External Quantum Efficiency of 19.2% Achieved in Light-Emitting Diodes of Colloidal Quantum Wells Enabled by Hot-Injection Shell Growth. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905824. [PMID: 31867764 DOI: 10.1002/adma.201905824] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/13/2019] [Indexed: 06/10/2023]
Abstract
Colloidal quantum wells (CQWs) are regarded as a highly promising class of optoelectronic materials, thanks to their unique excitonic characteristics of high extinction coefficients and ultranarrow emission bandwidths. Although the exploration of CQWs in light-emitting diodes (LEDs) is impressive, the performance of CQW-LEDs lags far behind other types of soft-material LEDs (e.g., organic LEDs, colloidal-quantum-dot LEDs, and perovskite LEDs). Herein, high-efficiency CQW-LEDs reaching close to the theoretical limit are reported. A key factor for this high performance is the exploitation of hot-injection shell (HIS) growth of CQWs, which enables a near-unity photoluminescence quantum yield (PLQY), reduces nonradiative channels, ensures smooth films, and enhances the stability. Remarkably, the PLQY remains 95% in solution and 87% in film despite rigorous cleaning. Through systematically understanding their shape-, composition-, and device-engineering, the CQW-LEDs using CdSe/Cd0.25 Zn0.75 S core/HIS CQWs exhibit a maximum external quantum efficiency of 19.2%. Additionally, a high luminance of 23 490 cd m-2 , extremely saturated red color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.715, 0.283), and stable emission are obtained. The findings indicate that HIS-grown CQWs enable high-performance solution-processed LEDs, which may pave the path for future CQW-based display and lighting technologies.
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Affiliation(s)
- Baiquan Liu
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Yemliha Altintas
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
- Department of Materials Science and Nanotechnology and Department of Electrical-Electronics Engineering, Abdullah Gül University, Kayseri, TR-38080, Turkey
| | - Lin Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Sushant Shendre
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Manoj Sharma
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
| | - Handong Sun
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Evren Mutlugun
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
- Department of Materials Science and Nanotechnology and Department of Electrical-Electronics Engineering, Abdullah Gül University, Kayseri, TR-38080, Turkey
| | - Hilmi Volkan Demir
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
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10
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Shi S, Liu Y, Nie M, Wang Q. Nacre-Mimetic Polypropylene Featuring Heterogeneous Distribution of Polymorphic Compositions via Controlled Diffusion of β-Nucleating Agent. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.8b06244] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shaohong Shi
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Yuansen Liu
- Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, China
| | - Min Nie
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Qi Wang
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China
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11
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Kim SR, Lim CW. Microwave‐assisted Efficient H/D Exchange Method of 9H‐Carbazole and 2‐Phenylpyridine as Organic Light‐emitting Materials. B KOREAN CHEM SOC 2019. [DOI: 10.1002/bkcs.11642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Seo Ra Kim
- Department of Chemistry, College of Life Science and Nano technologyHannam University Daejeon 305‐811 Republic of Korea
| | - Choon Woo Lim
- Department of Chemistry, College of Life Science and Nano technologyHannam University Daejeon 305‐811 Republic of Korea
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12
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Yun J, Kim J, Jung BJ, Kim G, Kwak J. Enhanced efficiency and high temperature stability of hybrid quantum dot light-emitting diodes using molybdenum oxide doped hole transport layer. RSC Adv 2019; 9:16252-16257. [PMID: 35521376 PMCID: PMC9064386 DOI: 10.1039/c9ra02946j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 05/18/2019] [Indexed: 11/21/2022] Open
Abstract
High power efficiency (PE) and stability of quantum dot (QD) light-emitting diodes (QLEDs) are important factors for practical use in various displays. However, hybrid QLEDs consisting of an organic hole transport layer (HTL) and an inorganic electron transport layer (ETL) sometimes have poor stability due to the low thermal stability of the organic HTL. To solve the problem, here, we report enhanced efficiency, lifetime, and temperature stability in inverted and hybrid structured QLEDs by adopting a MoO3-doped HTL. Also, to improve the electron–hole charge carrier balance, a thin insulating interlayer was used between QDs and the ETL. As a result, the QLED with the p-doped HTL exhibited the increased PE by ∼28% and longer lifetime compared to the pristine QLEDs. In addition, the QLED showed stable operation at the high temperature up to 400 K, whereas the control device failed to operate at 375 K. We systematically investigated the effect of the MoO3-doping on the performance and thermal stability of the QLEDs. We believe that QLEDs with the p-doped HTL can be used for further QLED researches to simultaneously improve the efficiency, lifetime, and high temperature stability, which are highly required for their use in automotive and outdoor displays. QLEDs introducing a p-doped HTL exhibit stable operation at high temperature up to 400 K.![]()
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Affiliation(s)
- Jinyoung Yun
- School of Electrical Engineering
- Korea University
- Seoul 02841
- South Korea
| | - Jaeyun Kim
- School of Electrical and Computer Engineering
- University of Seoul
- Seoul 02504
- South Korea
| | - Byung Jun Jung
- Department of Materials Science and Engineering
- University of Seoul
- Seoul 02504
- South Korea
| | - Gyutae Kim
- School of Electrical Engineering
- Korea University
- Seoul 02841
- South Korea
| | - Jeonghun Kwak
- Department of Electrical and Computer Engineering
- Inter-University Semiconductor Research Center
- Seoul National University
- Seoul 08826
- South Korea
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13
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Ràfols-Ribé J, Vila-Costa A, Rodríguez-Tinoco C, Lopeandía AF, Rodríguez-Viejo J, Gonzalez-Silveira M. Kinetic arrest of front transformation to gain access to the bulk glass transition in ultrathin films of vapour-deposited glasses. Phys Chem Chem Phys 2018; 20:29989-29995. [PMID: 30480265 DOI: 10.1039/c8cp06264a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Physical vapour deposition has emerged as the technique to obtain glasses of unbeatable stability. However, vapour deposited glasses exhibit a different transformation mechanism to ordinary glasses produced from liquid. Vapour deposited glasses of different thermodynamic stability, from ultrastable to those similar to ordinary glasses, transform into the liquid state via front propagation starting at the most mobile surfaces/interfaces, at least for the first stages of the transformation, eventually dynamiting the high thermal stability achieved for some of these glasses. A previous study showed that it was possible to avoid this transformation front by capping the films with a higher Tg material. We show here fast calorimetry measurements on TPD and IMC vapour deposited glasses capped respectively with TCTA and TPD. This capped configuration is very effective in suppressing the heterogeneous transformation of the stable glasses into the supercooled liquid and shifts the devitrification temperature to much higher values, where the bulk homogeneous mechanism becomes active. This approach may be useful to further study the bulk glass transition in thin films.
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Affiliation(s)
- Joan Ràfols-Ribé
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, Barcelona, 08193 - Bellaterra, Spain.
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14
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Matsuoka K, Albrecht K, Nakayama A, Yamamoto K, Fujita K. Highly Efficient Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes with Fully Solution-Processed Organic Multilayered Architecture: Impact of Terminal Substitution on Carbazole-Benzophenone Dendrimer and Interfacial Engineering. ACS APPLIED MATERIALS & INTERFACES 2018; 10:33343-33352. [PMID: 30187748 DOI: 10.1021/acsami.8b09451] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A series of second-generation carbazole-benzophenone dendrimer substituted by several functional groups at terminal positions (subG2B) was investigated toward a thermally activated delayed fluorescence (TADF) emitter for nondoped emissive layer (EML) application in a solution-processed organic light-emitting diode (OLED). Substitution was found to dramatically alter the photophysical properties of the dendritic TADF emitters. The introduction of tert-butyl and phenyl group endows the subG2Bs with aggregation-induced emission enhancement character by suppression of internal conversion in singlet excited states. In the meantime, the introduction of a methoxy group resulted in aggregation-caused quenching character. The device performance of the OLED, where subG2B neat films were incorporated as nondoped EMLs, was found to be highly enhanced by adopting fully solution-processed organic multilayer architecture in comparison to the devices with a vacuum-deposited electron transporting layer (ETL), achieving a maximum external quantum efficiency of 17.0%. Such improvement was attributable to the improved carrier balance via intermixing at solution-processed EML/ETL interfaces. It was also found that the post-thermal annealing of the OLED at appropriate temperatures could be beneficial to enhance OLED performance by promoting the intermixing EML/ETL interface to some extent. Our findings emphasize the potential utility of dendritic TADF emitters in the solution-processed TADF-OLED and increase the importance to manipulate dendrimer/small molecule interfaces.
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Affiliation(s)
- Kenichi Matsuoka
- Institute for Materials Chemistry and Engineering , Kyushu University , 6-1 Kasuga koen , Kasuga, Fukuoka 816-8580 , Japan
| | | | - Akira Nakayama
- Institute for Catalysis , Hokkaido University , Sapporo 001-0021 , Japan
| | | | - Katsuhiko Fujita
- Institute for Materials Chemistry and Engineering , Kyushu University , 6-1 Kasuga koen , Kasuga, Fukuoka 816-8580 , Japan
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15
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Hung SF, Fang PH, Wei Y, Tsai FY, Chen CT, Kimura T, Samori S, Fujitsuka M, Majima T, Lin CH, Peng SH, Jou JH. Spirally Configured ( cis-Stilbene) Trimers: Steady-State and Time-Resolved Photophysical Studies and Organic Light-Emitting Diode Applications. ACS APPLIED MATERIALS & INTERFACES 2018; 10:25561-25569. [PMID: 30028583 DOI: 10.1021/acsami.8b06137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This article reports for the time-resolved photophysical studies of spirally configured ( cis-stilbene) trimers and their spin-coated organic light-emitting diode (OLED) device performances. Transient absorption profiles of spirally configured, ter-( cis-stilbene) were studied by pulse radiolysis. The emission profiles after charge recombination of their incipient radical ions in benzene provides insights into the emission mechanism and efficiency in OLED devices. Blue-, sky blue-, and green-emitting OLED devices for a maximum external quantum efficiency are 4.32%, 4.70%, and 2.77%, respectively, by solution process.
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Affiliation(s)
| | | | - Yi Wei
- Department of Chemistry , Tamkang University , 151, Yingzhuan Rd , Tamsui Dist., New Taipei City , Taiwan , ROC
| | | | | | - Takumi Kimura
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Shingo Samori
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
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16
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McEwan JA, Clulow AJ, Nelson A, Jansen-van Vuuren RD, Burn PL, Gentle IR. Morphology of OLED Film Stacks Containing Solution-Processed Phosphorescent Dendrimers. ACS APPLIED MATERIALS & INTERFACES 2018; 10:3848-3855. [PMID: 29356504 DOI: 10.1021/acsami.7b15542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organic light-emitting devices containing solution-processed emissive dendrimers can be highly efficient. The most efficient devices contain a blend of the light-emitting dendrimer in a host and one or more charge-transporting layers. Using neutron reflectometry measurements with in situ photoluminescence, we have investigated the structure of the as-formed film as well as the changes in film structure and dendrimer emission under thermal stress. It was found that the as-formed film stacks comprising poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/host:dendrimer/1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (where the host was deuterated 4,4'-N,N'-di(carbazolyl)biphenyl or tris(4-carbazol-9-ylphenyl)amine, the host:dendrimer layer was solution-processed, and the 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene evaporated) had well-defined interfaces, indicating good wetting of each of the layers by the subsequently deposited layer. Upon thermal annealing, there was no change in the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/host:dendrimer interface, but once the temperature reached above the Tg of the host:dendrimer layer, it became a supercooled liquid into which 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene dissolved. When the film stacks were held at a temperature just above the onset of the diffusion process, they underwent an initial relatively fast diffusion process before reaching a quasi-stable state at that temperature.
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Affiliation(s)
- Jake A McEwan
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, QLD 4072, Australia
| | - Andrew J Clulow
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, QLD 4072, Australia
| | - Andrew Nelson
- Australian Nuclear Science and Technology Organisation , Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Ross D Jansen-van Vuuren
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, QLD 4072, Australia
| | - Paul L Burn
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, QLD 4072, Australia
| | - Ian R Gentle
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, QLD 4072, Australia
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