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Ma S, Cao F, Jia G, Wu Q, Wang S, Yang X. Blue ZnSeTe quantum dot light-emitting diodes with low efficiency roll-off enabled by an in situ hybridization of ZnMgO nanoparticles and amino alcohol molecules. NANOSCALE 2024; 16:10441-10447. [PMID: 38742531 DOI: 10.1039/d4nr01515k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
ZnSeTe quantum dots (QDs) have been employed as promising emitters for blue QD-based light-emitting diodes (QLEDs) due to their unique optoelectronic properties and environmental friendliness. However, such QLEDs usually suffer from serious efficiency roll-off primarily stemming from exciton loss at the interface of the QD layer and the ZnMgO (ZMO) electron transport layer (ETL), which remarkably hinders their application in flat-panel displays. Herein, we propose an in situ hybridization strategy that involves the pre-introduction of amino alcohols into the reaction solution. This strategy effectively suppresses the nucleophilic condensation process by facilitating the coordination of ammonium and hydroxyl groups with metal cations (M2+, i.e. Zn2+ and Mg2+). It slows down the growth rate of ZMO nanoparticles (NPs) while simultaneously facilitating M-O coordination, resulting in the synthesis of small-sized and low-defect ZMO NPs. Notably, this in situ hybridization approach not only alleviates emission quenching at the QDs/ETL interface but also elevates the energy level of the ETL for enhancing carrier injection. We further investigated the impact of amino alcohols with varying carbon-chain lengths on the performance of ZMO NPs and the corresponding LED devices. The optimal blue ZnSeTe QLED demonstrates an impressive EQE of 8.6% with only an ∼11% drop when the current density is increased to 200 mA cm-2, and the device operating lifetime extends to over 1300 h. Conversely, the device utilizing traditionally post-treated ZMO NPs as the ETL exhibits 45% efficiency roll-off and device lifetime of merely 190 h.
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Affiliation(s)
- Shaolin Ma
- Shanghai University Microelectronic R&D Center, Shanghai University, Shanghai 201900, P. R. China
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, P. R. China.
| | - Fan Cao
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, P. R. China.
| | - Guohua Jia
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Qianqian Wu
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, P. R. China.
| | - Sheng Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, P. R. China.
| | - Xuyong Yang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, P. R. China.
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Šarić A, Despotović I. Hydrogen Bonds as Stability-Controlling Elements of Spherical Aggregates of ZnO Nanoparticles: A Joint Experimental and Theoretical Approach. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4843. [PMID: 37445157 DOI: 10.3390/ma16134843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
The effects of various organic additives, such as diethanolamine (DEA) and ethanolamine (EA), and variations in aging times on the formation and stability mechanisms of spherical aggregates of ZnO nanoparticles (NPs) prepared by using solvothermal synthesis were studied. The experimental results of the structural, morphological and optical properties monitored by using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM) and UV-Vis spectroscopy were supported by quantum chemical calculations at the level of density functional theory (DFT). Understanding the mechanism of spherical ZnO aggregate formation and its stability by mimicking the processes at the computer level was achieved through theoretical simulations of the ZnO surface/additive interactions using (ZnO)36-DEA and (ZnO)36-EA models. The fine-tuned spherical aggregation of ZnO nanoparticles was driven by various interactions, in particular, strong O-H∙∙∙O and weak N-H∙∙∙O hydrogen bonds as controlling interactions. The calculated negative free release energy, ∆G*INT, indicates that the ZnO surface/additive interaction in diethanolamine media is a spontaneous exergonic process (∆G*INT = -7.73 kcal mol-1), whereas, in ethanolamine media, it is an unfavorable, slightly endergonic process (∆G*INT > 0). The presence of two strong O-H∙∙∙O hydrogen bonds and, at the same time, a weaker N-H∙∙∙O hydrogen bond is the key factor for the very good and long-term aggregate stability of ZnO NPs in DEA media. This integrated experimental-theoretical study highlights the stability and compactness of spherical ZnO aggregates of ZnO NPs, prepared in the presence of diethanolamine compared to ethanolamine media, and provides a promising method and flexible design of ZnO nanomaterials to improve their adsorptive and optical properties.
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Affiliation(s)
- Ankica Šarić
- Division of Materials Physics, Ruđer Bošković Institute, Centre of Excellence for Advanced Materials and Sensing Devices, Bijenička 54, HR-10002 Zagreb, Croatia
| | - Ines Despotović
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, HR-10002 Zagreb, Croatia
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Vilà A, Gómez-Núñez A, Alcobé X, Palacios S, Puig Walz T, López C. Influence of the Nature of Aminoalcohol on ZnO Films Formed by Sol-Gel Methods. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1057. [PMID: 36985951 PMCID: PMC10052816 DOI: 10.3390/nano13061057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
Here we present comparative studies of: (i) the formation of ZnO thin films via the sol-gel method using zinc acetate dihydrate (ZAD), 2-methoxyethanol (ME) as solvent, and the aminoalcohols (AA): ethanolamine, (S)-(+)-2-amino-1-propanol, (S)-(+)-2-amino-3-methyl-1-butanol, 2-aminophenol, and aminobenzyl alcohol, and (ii) elemental analyses, infrared spectroscopy, X-ray diffraction, scanning electron microscopy, absorption and emission spectra of films obtained after deposition by drop coating on glass surface, and thermal treatments at 300, 400, 500 and 600 °C. The results obtained provide conclusive evidences of the influence of the AA used (aliphatic vs. aromatic) on the ink stability (prior to deposition), and on the composition, structures, morphologies, and properties of films after calcination, in particular, those due to the different substituents, H, Me, or iPr, and to the presence or the absence of a -CH2 unit. Aliphatic films, more stable and purer than aromatic ones, contained the ZnO wurtzite form for all annealing temperatures, while the cubic sphalerite (zinc-blende) form was also detected after using aromatic AAs. Films having frayed fibers or quartered layers or uniform yarns evolved to "neuron-like" patterns. UV and photoluminescence studies revealed that these AAs also affect the optical band gap, the structural defects, and photo-optical properties of the films.
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Affiliation(s)
- Anna Vilà
- Department of Electronic and Biomedical Engineering, Faculty of Physics, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- Institute for Nanoscience and Nanotechnology–IN2UB, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Alberto Gómez-Núñez
- Department of Electronic and Biomedical Engineering, Faculty of Physics, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- Eurecat—Technology Centre of Catalonia, Av. Universitat Autònoma 23, 08290 Cerdanyola del Vallès, Spain
| | - Xavier Alcobé
- Centres Científics i Tecnològics (CCiTUB), University of Barcelona, C/Lluís Solé i Sabaris 1-3, 08028 Barcelona, Spain
| | - Sergi Palacios
- Department of Electronic and Biomedical Engineering, Faculty of Physics, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- Wallbox, Carrer del Foc 68, 08038 Barcelona, Spain
| | - Teo Puig Walz
- Department of Electronic and Biomedical Engineering, Faculty of Physics, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut EMI, Ernst-Zermelo-Straße 4, 79104 Freiburg im Breisgau, Germany
| | - Concepción López
- Department of Inorganic and Organic Chemistry (Section of Inorganic Chemistry), Faculty of Chemistry, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
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Nowak E, Chłopocka E, Szybowicz M, Stachowiak A, Koczorowski W, Piechowiak D, Miklaszewski A. The Influence of Aminoalcohols on ZnO Films’ Structure. Gels 2022; 8:gels8080512. [PMID: 36005113 PMCID: PMC9407612 DOI: 10.3390/gels8080512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 12/04/2022] Open
Abstract
Preparing structures with the sol-gel method often requires control of the basal plane of crystallites, crystallite structures, or the appearance of the voids. One of the critical factors in the formation of a layer are additives, such as aminoalcohols, which increase the control of the sol formation reaction. Since aminoalcohols differ in boiling points and alkalinity, their selection may play a significant role in the dynamics of structure formation. The main aim of this work is to examine the properties of ZnO layers grown using different aminoalcohols at different concentration rates. The layers were grown on various substrates, which would provide additional information on the behavior of the layers on a specific substrate, and the mixture was annealed at a relatively low temperature (400 °C). The research was conducted using monoethanolamine (MEA) and diethanolamine (DEA). The aminoalcohols were added to the solutions in equal concentrations. The microscopic image of the structure and the size of the crystallites were determined using micrographs. X-ray diffractometry and Raman spectroscopy were used for structural studies, phase analysis and to establish the purity of the obtained films. UV-vis absorption and photoluminescence were used to evaluate structural defects. This paper shows the influence of the stabilizer on the morphology of samples and the influence of the morphology and structure on the optical properties. The above comparison may allow the preparation of ZnO samples for specific applications.
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Affiliation(s)
- Ewelina Nowak
- Institute of Materials Research and Quantum Engineering, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
- Correspondence:
| | - Edyta Chłopocka
- Institute of Materials Research and Quantum Engineering, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - Mirosław Szybowicz
- Institute of Materials Research and Quantum Engineering, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - Alicja Stachowiak
- Institute of Physics, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - Wojciech Koczorowski
- Institute of Physics, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - Daria Piechowiak
- Institute of Materials Engineering, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - Andrzej Miklaszewski
- Institute of Materials Engineering, Faculty of Materials Engineering and Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
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Kovács Z, Molnár C, Gyulavári T, Magyari K, Tóth ZR, Baia L, Pap Z, Hernádi K. Solvothermal synthesis of ZnO spheres: tuning the structure and morphology from nano- to micro-meter range and its impact on their photocatalytic activity. Catal Today 2022. [DOI: 10.1016/j.cattod.2022.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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