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Philip A, Jussila T, Obenlüneschloß J, Zanders D, Preischel F, Kinnunen J, Devi A, Karppinen M. Conformal Zn-Benzene Dithiol Thin Films for Temperature-Sensitive Electronics Grown via Industry-Feasible Atomic/Molecular Layer Deposition Technique. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402608. [PMID: 38853133 DOI: 10.1002/smll.202402608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/17/2024] [Indexed: 06/11/2024]
Abstract
The atomic/molecular layer deposition (ALD/MLD) technique combining both inorganic and organic precursors is strongly emerging as a unique tool to design exciting new functional metal-organic thin-film materials. Here, this method is demonstrated to work even at low deposition temperatures and can produce highly stable and conformal thin films, fulfilling the indispensable prerequisites of today's 3D microelectronics and other potential industrial applications. This new ALD/MLD process is developed for Zn-organic thin films grown from non-pyrophoric bis-3-(N,N-dimethylamino)propyl zinc [Zn(DMP)2] and 1,4-benzene dithiol (BDT) precursors. This process yields air-stable Zn-BDT films with appreciably high growth per cycle (GPC) of 4.5 Å at 60 °C. The Zn/S ratio is determined at 0.5 with Rutherford backscattering spectrometry (RBS), in line with the anticipated (Zn─S─C6H6─S─)n bonding scheme. The high degree of conformality is shown using lateral high-aspect-ratio (LHAR) test substrates; scanning electron microscopy (SEM) analysis shows that the film penetration depth (PD) into the LHAR structure with cavity height of 500 nm is over 200 µm (i.e., aspect-ratio of 400). It is anticipated that the electrically insulating metal-organic Zn-BDT thin films grown via the solvent-free ALD/MLD technique, can be excellent barrier layers for temperature-sensitive and flexible electronic devices.
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Affiliation(s)
- Anish Philip
- Department of Chemistry and Materials Science, Aalto University, Espoo, FI-00076, Finland
- Chipmetrics Ltd, Joensuu, 80130, Finland
| | - Topias Jussila
- Department of Chemistry and Materials Science, Aalto University, Espoo, FI-00076, Finland
| | | | - David Zanders
- Inorganic Materials Chemistry, Ruhr University Bochum, 44801, Bochum, Germany
| | - Florian Preischel
- Inorganic Materials Chemistry, Ruhr University Bochum, 44801, Bochum, Germany
| | | | - Anjana Devi
- Inorganic Materials Chemistry, Ruhr University Bochum, 44801, Bochum, Germany
- Leibniz Institute for Solid State and Materials Research, 01069, Dresden, Germany
- Chair of Materials Chemistry, Dresden University of Technology, 01069, Dresden, Germany
| | - Maarit Karppinen
- Department of Chemistry and Materials Science, Aalto University, Espoo, FI-00076, Finland
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2
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Shen C, Yin Z, Collins F, Pinna N. Atomic Layer Deposition of Metal Oxides and Chalcogenides for High Performance Transistors. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104599. [PMID: 35712776 PMCID: PMC9376853 DOI: 10.1002/advs.202104599] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/23/2022] [Indexed: 06/15/2023]
Abstract
Atomic layer deposition (ALD) is a deposition technique well-suited to produce high-quality thin film materials at the nanoscale for applications in transistors. This review comprehensively describes the latest developments in ALD of metal oxides (MOs) and chalcogenides with tunable bandgaps, compositions, and nanostructures for the fabrication of high-performance field-effect transistors. By ALD various n-type and p-type MOs, including binary and multinary semiconductors, can be deposited and applied as channel materials, transparent electrodes, or electrode interlayers for improving charge-transport and switching properties of transistors. On the other hand, MO insulators by ALD are applied as dielectrics or protecting/encapsulating layers for enhancing device performance and stability. Metal chalcogenide semiconductors and their heterostructures made by ALD have shown great promise as novel building blocks to fabricate single channel or heterojunction materials in transistors. By correlating the device performance to the structural and chemical properties of the ALD materials, clear structure-property relations can be proposed, which can help to design better-performing transistors. Finally, a brief concluding remark on these ALD materials and devices is presented, with insights into upcoming opportunities and challenges for future electronics and integrated applications.
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Affiliation(s)
- Chengxu Shen
- Institut für Chemie and IRIS AdlershofHumboldt‐Universität zu BerlinBrook‐Taylor‐Str. 2Berlin12489Germany
| | - Zhigang Yin
- Institut für Chemie and IRIS AdlershofHumboldt‐Universität zu BerlinBrook‐Taylor‐Str. 2Berlin12489Germany
- State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of MatterChinese Academy of Sciences155 Yangqiao West RoadFuzhouFujian350002China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of ChinaFuzhouFujian350108China
| | - Fionn Collins
- Institut für Chemie and IRIS AdlershofHumboldt‐Universität zu BerlinBrook‐Taylor‐Str. 2Berlin12489Germany
| | - Nicola Pinna
- Institut für Chemie and IRIS AdlershofHumboldt‐Universität zu BerlinBrook‐Taylor‐Str. 2Berlin12489Germany
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3
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Abstract
Perovskite solar cells (PSCs) have captured the attention of the global energy research community in recent years by showing an exponential augmentation in their performance and stability. The supremacy of the light-harvesting efficiency and wider band gap of perovskite sensitizers have led to these devices being compared with the most outstanding rival silicon-based solar cells. Nevertheless, there are some issues such as their poor lifetime stability, considerable J–V hysteresis, and the toxicity of the conventional constituent materials which restrict their prevalence in the marketplace. The poor stability of PSCs with regard to humidity, UV radiation, oxygen and heat especially limits their industrial application. This review focuses on the in-depth studies of different direct and indirect parameters of PSC device instability. The mechanism for device degradation for several parameters and the complementary materials showing promising results are systematically analyzed. The main objective of this work is to review the effectual strategies of enhancing the stability of PSCs. Several important factors such as material engineering, novel device structure design, hole-transporting materials (HTMs), electron-transporting materials (ETMs), electrode materials preparation, and encapsulation methods that need to be taken care of in order to improve the stability of PSCs are discussed extensively. Conclusively, this review discusses some opportunities for the commercialization of PSCs with high efficiency and stability.
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Choi D. Electrochemical Analysis of Polymer Membrane with Inorganic Nanoparticles for High-Temperature PEM Fuel Cells. MEMBRANES 2022; 12:membranes12070680. [PMID: 35877885 PMCID: PMC9324827 DOI: 10.3390/membranes12070680] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 02/04/2023]
Abstract
In order to solve the challenge that battery performance rapidly deteriorates at a high temperature condition of 100 °C or higher, ZrO2-TiO2 (ZT) with various Zr:Ti ratios synthesized by a sol-gel method were impregnated in a Nafion membrane. Through material characterization, a unique ZT crystal phase peak with a Zr-O-Ti bond was identified, and the band range associated with this bond and intrinsic functional group region could be identified. These prepared powders were blended with 10% (w/w) Nafion-water dispersion to prepare composite Nafion membranes (NZTs). The water uptake increased and the ion exchange capacity decreased as the TiO2 content increased in the NZTs in which particles were uniformly distributed. These results were superior to those of the conventional Nafion 112. The electrochemical properties of all membranes was measured using a polarization curve in a single cell with a reaction area of 9 cm2, and the operating conditions in humidified H2/air was 120 °C under 50% relative humidity (RH) and 2 atm. The composite membrane cell with nanoparticles of a Zr:Ti ratio of 1:3 (NZT13) exhibited the best electrochemical characteristics. These results can be explained by the improved physicochemical properties of NZT13, such as optimized water content and ion exchange capacity, strong intermolecular forces acting between water and nanofillers (δ), and increased torsion by the fillers (τ). The results of this study show that the NZT membrane can replace a conventional membrane under high-temperature and low-humidity conditions. To examine the effect of the content of the inorganic nanomaterials in the composite membrane, a composite membrane (NZT-20, NZT-30) having an inorganic nano-filler content of 20 or 30% (w/w) was also prepared. The performance was high in the order of NZT13, NZT-20, and NZT-30. This shows that not only the operating conditions but also the particle content can significantly affect the performance.
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Affiliation(s)
- DongWoong Choi
- Department of Chemical Engineering, Dong-Eui University, Busan 47340, Korea
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5
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Kim HG, Hong DH, Yoo JH, Lee HC. Effect of Process Temperature on Density and Electrical Characteristics of Hf0.5Zr0.5O2 Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition. NANOMATERIALS 2022; 12:nano12030548. [PMID: 35159892 PMCID: PMC8839501 DOI: 10.3390/nano12030548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023]
Abstract
HfxZr1−xO2 (HZO) thin films have excellent potential for application in various devices, including ferroelectric transistors and semiconductor memories. However, such applications are hindered by the low remanent polarization (Pr) and fatigue endurance of these films. To overcome these limitations, in this study, HZO thin films were fabricated via plasma-enhanced atomic layer deposition (PEALD), and the effects of the deposition and post-annealing temperatures on the density, crystallinity, and electrical properties of the thin films were analyzed. The thin films obtained via PEALD were characterized using cross-sectional transmission electron microscopy images and energy-dispersive spectroscopy analysis. An HZO thin film deposited at 180 °C exhibited the highest o-phase proportion as well as the highest density. By contrast, mixed secondary phases were observed in a thin film deposited at 280 °C. Furthermore, a post-annealing temperature of 600 °C yielded the highest thin film density, and the highest 2Pr value and fatigue endurance were obtained for the film deposited at 180 °C and post-annealed at 600 °C. In addition, we developed three different methods to further enhance the density of the films. Consequently, an enhanced maximum density and exceptional fatigue endurance of 2.5 × 107 cycles were obtained.
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Philip A, Mai L, Ghiyasi R, Devi A, Karppinen M. Low-temperature ALD/MLD growth of alucone and zincone thin films from non-pyrophoric precursors. Dalton Trans 2022; 51:14508-14516. [DOI: 10.1039/d2dt02279f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combined atomic/molecular layer deposition (ALD/MLD) technique is emerging as a state-of-the-art synthesis route for new metal-organic thin-film materials with a multitude of properties by combining those of the inorganic...
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7
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Han JH, Lee SH, Jeong SG, Kim DY, Yang HL, Lee S, Yoo SY, Park I, Park HB, Lim KS, Yang WJ, Choi HC, Park JS. Atomic-Layer-Deposited SiO x/SnO x Nanolaminate Structure for Moisture and Hydrogen Gas Diffusion Barriers. ACS APPLIED MATERIALS & INTERFACES 2021; 13:39584-39594. [PMID: 34383478 DOI: 10.1021/acsami.1c09901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High-density SnOx and SiOx thin films were deposited via atomic layer deposition (ALD) at low temperatures (100 °C) using tetrakis(dimethylamino)tin(IV) (TDMASn) and di-isopropylaminosilane (DIPAS) as precursors and hydrogen peroxide (H2O2) and O2 plasma as reactants, respectively. The thin-film encapsulation (TFE) properties of SnOx and SiOx were demonstrated with thickness dependence measurements of the water vapor transmission rate (WVTR) evaluated at 50 °C and 90% relative humidity, and different TFE performance tendencies were observed between thermal and plasma ALD SnOx. The film density, crystallinity, and pinholes formed in the SnOx film appeared to be closely related to the diffusion barrier properties of the film. Based on the above results, a nanolaminate (NL) structure consisting of SiOx and SnOx deposited using plasma-enhanced ALD was measured using WVTR (H2O molecule diffusion) at 2.43 × 10-5 g/m2 day with a 10/10 nm NL structure and time-lag gas permeation measurement (H2 gas diffusion) for applications as passivation layers in various electronic devices.
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Affiliation(s)
- Ju-Hwan Han
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seong-Hyeon Lee
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seok-Goo Jeong
- Division of Nanoscale Semiconductor Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Dong-Yeon Kim
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Hae Lin Yang
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seunghwan Lee
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seung Yeon Yoo
- Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Inho Park
- Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Ho Bum Park
- Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Kwang-Su Lim
- E2 Block LG Science Park (LG Display), 30, Magokjungang 10-ro, Gangseo-gu, Seoul 07796, Republic of Korea
| | - Won-Jae Yang
- E2 Block LG Science Park (LG Display), 30, Magokjungang 10-ro, Gangseo-gu, Seoul 07796, Republic of Korea
| | - Hyun-Chul Choi
- E2 Block LG Science Park (LG Display), 30, Magokjungang 10-ro, Gangseo-gu, Seoul 07796, Republic of Korea
| | - Jin-Seong Park
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
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8
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Ilhom S, Mohammad A, Shukla D, Grasso J, Willis BG, Okyay AK, Biyikli N. Low-Temperature As-Grown Crystalline β-Ga 2O 3 Films via Plasma-Enhanced Atomic Layer Deposition. ACS APPLIED MATERIALS & INTERFACES 2021; 13:8538-8551. [PMID: 33566585 DOI: 10.1021/acsami.0c21128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report on the low-temperature growth of crystalline Ga2O3 films on Si, sapphire, and glass substrates using plasma-enhanced atomic layer deposition (PEALD) featuring a hollow-cathode plasma source. Films were deposited by using triethylgallium (TEG) and Ar/O2 plasma as metal precursor and oxygen co-reactant, respectively. Growth experiments have been performed within 150-240 °C substrate temperature and 30-300 W radio-frequency (rf) plasma power ranges. Additionally, each unit AB-type ALD cycle was followed by an in situ Ar plasma annealing treatment, which consisted of an extra (50-300 W) Ar plasma exposure for 20 s ending just before the next TEG pulse. The growth per cycle (GPC) of the films without Ar plasma annealing step ranged between 0.69 and 1.31 Å/cycle, and as-grown refractive indices were between 1.67 and 1.75 within the scanned plasma power range. X-ray diffraction (XRD) measurements showed that Ga2O3 films grown without in situ Ar plasma annealing exhibited amorphous character irrespective of substrate temperature and rf power values. With the incorporation of the in situ Ar plasma annealing process, the GPC of Ga2O3 films ranged between 0.76 and 1.03 Å/cycle along with higher refractive index values of 1.75-1.79. The increased refractive index (1.79) and slightly reduced GPC (1.03 Å/cycle) at 250 W plasma annealing indicated possible densification and crystallization of the films. Indeed, X-ray measurements confirmed that in situ plasma annealed films grow in a monoclinic β-Ga2O3 crystal phase. The film crystallinity and density further enhance (from 5.11 to 5.60 g/cm3) by increasing the rf power value used during in situ Ar plasma annealing process. X-ray photoelectron spectroscopy (XPS) measurement of the β-Ga2O3 sample grown under optimal in situ plasma annealing power (250 W) revealed near-ideal film stoichiometry (O/Ga of ∼1.44) with relatively low carbon content (∼5 at. %), whereas 50 W rf power treated film was highly non-stoichiometric (O/Ga of ∼2.31) with considerably elevated carbon content. Our results demonstrate the effectiveness of in situ Ar plasma annealing process to transform amorphous wide bandgap oxide semiconductors into crystalline films without needing high-temperature post-deposition annealing treatment.
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Affiliation(s)
- Saidjafarzoda Ilhom
- Department of Electrical & Computer Engineering, University of Connecticut, 371 Fairfield Way, Storrs, Connecticut 06269, United States
| | - Adnan Mohammad
- Department of Electrical & Computer Engineering, University of Connecticut, 371 Fairfield Way, Storrs, Connecticut 06269, United States
| | - Deepa Shukla
- Department of Electrical & Computer Engineering, University of Connecticut, 371 Fairfield Way, Storrs, Connecticut 06269, United States
- Department of Materials Science & Engineering, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - John Grasso
- Department of Chemical and Biomolecular Engineering, University of Connecticut, 191 Auditorium Road, Storrs, Connecticut 06269, United States
| | - Brian G Willis
- Department of Chemical and Biomolecular Engineering, University of Connecticut, 191 Auditorium Road, Storrs, Connecticut 06269, United States
| | - Ali Kemal Okyay
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
| | - Necmi Biyikli
- Department of Electrical & Computer Engineering, University of Connecticut, 371 Fairfield Way, Storrs, Connecticut 06269, United States
- Department of Materials Science & Engineering, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269, United States
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9
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Hansen PA, Zikmund T, Yu T, Kvalvik JN, Aarholt T, Prytz Ø, Meijerink A, Nilsen O. Single-step approach to sensitized luminescence through bulk-embedded organics in crystalline fluorides. Commun Chem 2020; 3:162. [PMID: 36703339 PMCID: PMC9814844 DOI: 10.1038/s42004-020-00410-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/09/2020] [Indexed: 01/29/2023] Open
Abstract
Luminescent materials enable warm white LEDs, molecular tagging, enhanced optoelectronics and can improve energy harvesting. With the recent development of multi-step processes like down- and upconversion and the difficulty in sensitizing these, it is clear that optimizing all properties simultaneously is not possible within a single material class. In this work, we have utilized the layer-by-layer approach of atomic layer deposition to combine broad absorption from an aromatic molecule with the high emission yields of crystalline multi-layer lanthanide fluorides in a single-step nanocomposite process. This approach results in complete energy transfer from the organic molecule while providing inorganic fluoride-like lanthanide luminescence. Sm3+ is easily quenched by organic sensitizers, but in our case we obtain strong fluoride-like Sm3+ emission sensitized by strong UV absorption of terephthalic acid. This design allows combinations of otherwise incompatible species, both with respect to normally incompatible synthesis requirements and in controlling energy transfer and quenching routes.
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Affiliation(s)
- Per-Anders Hansen
- grid.5510.10000 0004 1936 8921Department of Chemistry, University of Oslo, Oslo, Norway
| | - Tomas Zikmund
- grid.5510.10000 0004 1936 8921Department of Chemistry, University of Oslo, Oslo, Norway ,grid.418095.10000 0001 1015 3316Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ting Yu
- grid.5477.10000000120346234Debye Institute for NanoMaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Julie Nitsche Kvalvik
- grid.5510.10000 0004 1936 8921Department of Chemistry, University of Oslo, Oslo, Norway
| | - Thomas Aarholt
- grid.5510.10000 0004 1936 8921Department of Physics, University of Oslo, Oslo, Norway
| | - Øystein Prytz
- grid.5510.10000 0004 1936 8921Department of Physics, University of Oslo, Oslo, Norway
| | - Andries Meijerink
- grid.5477.10000000120346234Debye Institute for NanoMaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Ola Nilsen
- grid.5510.10000 0004 1936 8921Department of Chemistry, University of Oslo, Oslo, Norway
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10
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Wu S, Li Y, Lian H, Lévêque G, Grandidier B, Adam PM, Gérard D, Bachelot R, Xu T, Wei B. Hybrid nanostructured plasmonic electrodes for flexible organic light-emitting diodes. NANOTECHNOLOGY 2020; 31:375203. [PMID: 32434165 DOI: 10.1088/1361-6528/ab94df] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Improved performance in flexible organic light-emitting diodes (OLEDs) is demonstrated by using a hybrid nanostructured plasmonic electrode consisting of silver nanowires (AgNWs) decorated with silver nanoparticles (AgNPs) and covered by exfoliated graphene sheets. Such all-solution processed electrodes show high optical transparency and electrical conductivity. When integrated in an OLED with super yellow polyphenylene vinylene as the emissive layer, the plasmon coupling of the NW-NP hybrid plasmonic system is found to significantly enhance the fluorescence, demonstrated by both simulations and photoluminescence measurements, leading to a current efficiency of 11.61 cd A-1 and a maximum luminance of 20 008 cd m-2 in OLEDs. Stress studies reveal a superior mechanical flexibility to the commercial indium-tin-oxide (ITO) counterparts, due to the incorporation of exfoliated graphene sheets. Our results show that these hybrid nanostructured plasmonic electrodes can be applied as an effective alternative to ITO for use in high-performance flexible OLEDs.
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Affiliation(s)
- Shiwei Wu
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 200072, Shanghai, People's Republic of China
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11
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Philip A, Niemelä JP, Tewari GC, Putz B, Edwards TEJ, Itoh M, Utke I, Karppinen M. Flexible ε-Fe 2O 3-Terephthalate Thin-Film Magnets through ALD/MLD. ACS APPLIED MATERIALS & INTERFACES 2020; 12:21912-21921. [PMID: 32324991 PMCID: PMC7685534 DOI: 10.1021/acsami.0c04665] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/23/2020] [Indexed: 05/24/2023]
Abstract
Pliable and lightweight thin-film magnets performing at room temperature are indispensable ingredients of the next-generation flexible electronics. However, conventional inorganic magnets based on f-block metals are rigid and heavy, whereas the emerging organic/molecular magnets are inferior regarding their magnetic characteristics. Here we fuse the best features of the two worlds, by tailoring ε-Fe2O3-terephthalate superlattice thin films with inbuilt flexibility due to the thin organic layers intimately embedded within the ferrimagnetic ε-Fe2O3 matrix; these films are also sustainable as they do not contain rare heavy metals. The films are grown with sub-nanometer-scale accuracy from gaseous precursors using the atomic/molecular layer deposition (ALD/MLD) technique. Tensile tests confirm the expected increased flexibility with increasing organic content reaching a 3-fold decrease in critical bending radius (2.4 ± 0.3 mm) as compared to ε-Fe2O3 thin film (7.7 ± 0.3 mm). Most remarkably, these hybrid ε-Fe2O3-terephthalate films do not compromise the exceptional intrinsic magnetic characteristics of the ε-Fe2O3 phase, in particular the ultrahigh coercive force (∼2 kOe) even at room temperature.
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Affiliation(s)
- Anish Philip
- Department
of Chemistry and Materials Science, Aalto
University, Espoo FI-00076, Finland
| | - Janne-Petteri Niemelä
- Laboratory
for Mechanics of Materials and Nanostructures, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Girish C Tewari
- Department
of Chemistry and Materials Science, Aalto
University, Espoo FI-00076, Finland
| | - Barbara Putz
- Laboratory
for Mechanics of Materials and Nanostructures, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Thomas Edward James Edwards
- Laboratory
for Mechanics of Materials and Nanostructures, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Mitsuru Itoh
- Materials
and Structures Laboratory, Tokyo Institute
of Technology, 4259 Nagatsuta,
Midoriku, Yokohama 226-8503, Japan
| | - Ivo Utke
- Laboratory
for Mechanics of Materials and Nanostructures, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Maarit Karppinen
- Department
of Chemistry and Materials Science, Aalto
University, Espoo FI-00076, Finland
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12
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Structural, Optical and Electrical Properties of HfO 2 Thin Films Deposited at Low-Temperature Using Plasma-Enhanced Atomic Layer Deposition. MATERIALS 2020; 13:ma13092008. [PMID: 32344793 PMCID: PMC7254199 DOI: 10.3390/ma13092008] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/17/2020] [Accepted: 04/23/2020] [Indexed: 11/24/2022]
Abstract
HfO2 was deposited at 80–250 °C by plasma-enhanced atomic layer deposition (PEALD), and properties were compared with those obtained by using thermal atomic layer deposition (thermal ALD). The ALD window, i.e., the region where the growth per cycle (GPC) is constant, shifted from high temperatures (150–200 °C) to lower temperatures (80–150 °C) in PEALD. HfO2 deposited at 80 °C by PEALD showed higher density (8.1 g/cm3) than those deposited by thermal ALD (5.3 g/cm3) and a smooth surface (RMS Roughness: 0.2 nm). HfO2 deposited at a low temperature by PEALD showed decreased contaminants compared to thermal ALD deposited HfO2. Values of refractive indices and optical band gap of HfO2 deposited at 80 °C by PEALD (1.9, 5.6 eV) were higher than those obtained by using thermal ALD (1.7, 5.1 eV). Transparency of HfO2 deposited at 80 °C by PEALD on polyethylene terephthalate (PET) was high (> 84%). PET deposited above 80 °C was unable to withstand heat and showed deformation. HfO2 deposited at 80 °C by PEALD showed decreased leakage current from 1.4 × 10−2 to 2.5 × 10−5 A/cm2 and increased capacitance of approximately 21% compared to HfO2 using thermal ALD. Consequently, HfO2 deposited at a low temperature by PEALD showed improved properties compared to HfO2 deposited by thermal ALD.
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13
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Salari S, Ghodsi FE, Nadamani MP. 4-Nitro-Azo Dye-Sensitized Optical Behavior of Organic/Inorganic Hybrid Networks in Zirconium-Based Thin Films: Effect of Cu Co-doping. J Inorg Organomet Polym Mater 2020. [DOI: 10.1007/s10904-019-01345-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Singh AK, Adstedt K, Brown B, Singh PM, Graham S. Development of ALD Coatings for Harsh Environment Applications. ACS APPLIED MATERIALS & INTERFACES 2019; 11:7498-7509. [PMID: 30585719 DOI: 10.1021/acsami.8b11557] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Atomic layer deposition (ALD) is a well-known technique for the fabrication of ultrathin and highly conformal barrier coatings which have extensively been used for the protection of electronic devices in open atmospheric conditions. Here, we extend the scope for the application of low-temperature-deposited plasma-enhanced ALD barrier coatings for the protection of devices in a variety of chemical environments. The chemical stability tests were conducted in 3.5% NaCl, sea water, HCl (pH 4), and H2SO4 (pH 4) solutions for ALD Al2O3, HfO2, TiO2, and ZrO2, deposited at 100 °C on TiO2-coated Au and ALD ZnO (photoactive)-coated Si substrates. Using electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) study, various aspects of the barrier properties and performance of ALD films in harsh chemical environments were explored. We demonstrate that the combined approach involving EIS and PL provides unique insights into the suitability of ALD films as barriers in harsh environments involving ionic solutions. The observations from EIS and PL tests are supported by the X-ray photoelectron spectroscopy analysis of ALD materials. Of the materials tested, ALD TiO2 and ZrO2 were found to be the most stable, chemically, in all four solutions, whereas TiO2 was a better permeation barrier.
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Putkonen M, Sippola P, Svärd L, Sajavaara T, Vartiainen J, Buchanan I, Forsström U, Simell P, Tammelin T. Low-temperature atomic layer deposition of SiO 2/Al 2O 3 multilayer structures constructed on self-standing films of cellulose nanofibrils. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0037. [PMID: 29277735 PMCID: PMC5746552 DOI: 10.1098/rsta.2017.0037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/09/2017] [Indexed: 05/25/2023]
Abstract
In this paper, we have optimized a low-temperature atomic layer deposition (ALD) of SiO2 using AP-LTO® 330 and ozone (O3) as precursors, and demonstrated its suitability to surface-modify temperature-sensitive bio-based films of cellulose nanofibrils (CNFs). The lowest temperature for the thermal ALD process was 80°C when the silicon precursor residence time was increased by the stop-flow mode. The SiO2 film deposition rate was dependent on the temperature varying within 1.5-2.2 Å cycle-1 in the temperature range of 80-350°C, respectively. The low-temperature SiO2 process that resulted was combined with the conventional trimethyl aluminium + H2O process in order to prepare thin multilayer nanolaminates on self-standing CNF films. One to six stacks of SiO2/Al2O3 were deposited on the CNF films, with individual layer thicknesses of 3.7 nm and 2.6 nm, respectively, combined with a 5 nm protective SiO2 layer as the top layer. The performance of the multilayer hybrid nanolaminate structures was evaluated with respect to the oxygen and water vapour transmission rates. Six stacks of SiO2/Al2O with a total thickness of approximately 35 nm efficiently prevented oxygen and water molecules from interacting with the CNF film. The oxygen transmission rates analysed at 80% RH decreased from the value for plain CNF film of 130 ml m-2 d-1 to 0.15 ml m-2 d-1, whereas the water transmission rates lowered from 630 ± 50 g m-2 d-1 down to 90 ± 40 g m-2 d-1This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.
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Affiliation(s)
- Matti Putkonen
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
| | - Perttu Sippola
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, 02150 Espoo, Finland
| | - Laura Svärd
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
| | - Timo Sajavaara
- Department of Physics, University of Jyvaskyla, PO Box 35 (YFL), 40014 University of Jyvaskyla, Finland
| | - Jari Vartiainen
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
| | - Iain Buchanan
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195, USA
| | - Ulla Forsström
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
| | - Pekka Simell
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
| | - Tekla Tammelin
- VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
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