Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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6 pages, 1103 KB  
Article
Inkjet Printing of a Gate Insulator: Towards Fully Printable Organic Field Effect Transistor
by Huiwen Bai, Richard M. Voyles and Robert A. Nawrocki
Electron. Mater. 2024, 5(3), 160-165; https://doi.org/10.3390/electronicmat5030011 - 23 Aug 2024
Cited by 4 | Viewed by 1848
Abstract
In this work, a gate insulator poly (4-vinylphenol) (PVP) of an organic field effect transistor (OFET) was deposited using an inkjet printing technique, realized via a high printing resolution. Various parameters, including the molecular weight of PVP, printing direction, printing voltage, and drop [...] Read more.
In this work, a gate insulator poly (4-vinylphenol) (PVP) of an organic field effect transistor (OFET) was deposited using an inkjet printing technique, realized via a high printing resolution. Various parameters, including the molecular weight of PVP, printing direction, printing voltage, and drop frequency, were investigated to optimize OFET performance. Consequently, PVP with a smaller molecular weight of 11 k and a printing direction parallel to the channel, a printing voltage of 18 V, and a drop frequency of 10 kHz showed the best OFET performance. With a direct ink writing-printed organic semiconductor, this work paves the way for fully inkjet-printed OFETs. Full article
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11 pages, 3141 KB  
Article
Solution-Processable and Eco-Friendly Functionalization of Conductive Silver Nanoparticles Inks for Printable Electronics
by Sonia Ceron, David Barba and Miguel A. Dominguez
Electron. Mater. 2024, 5(2), 45-55; https://doi.org/10.3390/electronicmat5020004 - 16 Apr 2024
Cited by 3 | Viewed by 2793
Abstract
The functionalization of conductive inks has been carried out through the decomposition of hydrogen peroxide (H2O2) onto the surface of silver nanoparticles (AgNPs). The ink prepared using this eco-friendly chemical reagent has been characterized structurally, chemically, and morphologically, showing [...] Read more.
The functionalization of conductive inks has been carried out through the decomposition of hydrogen peroxide (H2O2) onto the surface of silver nanoparticles (AgNPs). The ink prepared using this eco-friendly chemical reagent has been characterized structurally, chemically, and morphologically, showing the presence of stable AgNPs with suitable properties as well as the absence of residual contamination. The electrical conductivity of such a solution-processable ink is evidenced for patterns designed on flexible photographic paper substrates, using a refillable fountain pen that is implemented as a printing mechanism for the fabrication of simple printed circuit boards (PCBs). The functionality and durability of the tested systems are demonstrated under various mechanical constraints, aiming to basically reproduce the normal operation conditions of flexible electronic devices. The obtained results indicate that the implementation of these AgNP-based inks is relevant for direct applications in inkjet printing technology, thus paving the way for the use of greener chemicals in ink preparation. Full article
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13 pages, 5579 KB  
Article
Insulator Metal Transition-Based Selector in Crossbar Memory Arrays
by Mahmoud Darwish and László Pohl
Electron. Mater. 2024, 5(1), 17-29; https://doi.org/10.3390/electronicmat5010002 - 23 Feb 2024
Cited by 5 | Viewed by 3221
Abstract
This article investigates resistive random access memory (ReRAM) crossbar memory arrays, which is a notable development in non-volatile memory technology. We highlight ReRAM’s competitive edge over NAND, NOR Flash, and phase-change memory (PCM), particularly in terms of endurance, speed, and energy efficiency. This [...] Read more.
This article investigates resistive random access memory (ReRAM) crossbar memory arrays, which is a notable development in non-volatile memory technology. We highlight ReRAM’s competitive edge over NAND, NOR Flash, and phase-change memory (PCM), particularly in terms of endurance, speed, and energy efficiency. This paper focuses on the architecture of crossbar arrays, where memristive devices are positioned at intersecting metal wires. We emphasize the unique resistive switching mechanisms of memristors and the challenges of sneak path currents and delve into the roles and configurations of selectors, particularly focusing on the one-selector one-resistor (1S1R) architecture with an insulator–metal transition (IMT) based selector. We use SPICE simulations based on defined models to examine a 3 × 3 1S1R ReRAM array with vanadium dioxide selectors and titanium dioxide film memristors, assessing the impact of ambient temperature and critical IMT temperatures on array performance. We highlight the operational regions of low resistive state (LRS) and high resistive state (HRS), providing insights into the electrical behavior of these components under various conditions. Lastly, we demonstrate the impact of selector presence on sneak path currents. This research contributes to the overall understanding of ReRAM crossbar arrays integrated with IMT material-based selectors. Full article
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12 pages, 5785 KB  
Article
Enhancing Light Harvesting in Dye-Sensitized Solar Cells through Mesoporous Silica Nanoparticle-Mediated Diffuse Scattering Back Reflectors
by Jeffrie Fina, Navdeep Kaur, Chen-Yu Chang, Cheng-Yu Lai and Daniela R. Radu
Electron. Mater. 2023, 4(3), 124-135; https://doi.org/10.3390/electronicmat4030010 - 30 Aug 2023
Cited by 7 | Viewed by 3212
Abstract
Dye-sensitized solar cells (DSSCs) hold unique promise in solar photovoltaics owing to their low-cost fabrication and high efficiency in ambient conditions. However, to improve their commercial viability, effective, and low-cost methods must be employed to enhance their light harvesting capabilities, and hence photovoltaic [...] Read more.
Dye-sensitized solar cells (DSSCs) hold unique promise in solar photovoltaics owing to their low-cost fabrication and high efficiency in ambient conditions. However, to improve their commercial viability, effective, and low-cost methods must be employed to enhance their light harvesting capabilities, and hence photovoltaic (PV) performance. Improving the absorption of incoming light is a critical strategy for maximizing solar cell efficiency while overcoming material limitations. Mesoporous silica nanoparticles (MSNs) were employed herein as a reflective layer on the back of transparent counter electrodes. Chemically synthesized MSNs were applied to DSSCs via bar coating as a facile fabrication step compatible with roll-to-roll manufacturing. The MSNs diffusely scatter the unused incident light transmitted through the DSSCs back into the photoactive layers, increasing the absorption of light by N719 dye molecules. This resulted in a 20% increase in power conversion efficiency (PCE), from 5.57% in a standard cell to 6.68% with the addition of MSNs. The improved performance is attributed to an increase in photon absorption which led to the generation of a higher number of charge carriers, thus increasing the current density in DSSCs. These results were corroborated with electrochemical impedance spectroscopy (EIS), which showed improved charge transport kinetics. The use of MSNs as reflectors proved to be an effective practical method for enhancing the performance of thin film solar cells. Due to silica’s abundance and biocompatibility, MSNs are an attractive material for meeting the low-cost and non-toxic requirements for commercially viable integrated PVs. Full article
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15 pages, 3349 KB  
Article
A Neural Network to Decipher Organic Electrochemical Transistors’ Multivariate Responses for Cation Recognition
by Sébastien Pecqueur, Dominique Vuillaume, Željko Crljen, Ivor Lončarić and Vinko Zlatić
Electron. Mater. 2023, 4(2), 80-94; https://doi.org/10.3390/electronicmat4020007 - 18 May 2023
Cited by 2 | Viewed by 2737
Abstract
Extracting relevant data from real-world experiments is often challenging with intrinsic materials and device property dispersion, such as in organic electronics. However, multivariate data analysis can often be a mean to circumvent this and to extract more information when larger datasets are used [...] Read more.
Extracting relevant data from real-world experiments is often challenging with intrinsic materials and device property dispersion, such as in organic electronics. However, multivariate data analysis can often be a mean to circumvent this and to extract more information when larger datasets are used with learning algorithms instead of physical models. Here, we report on identifying relevant information descriptors for organic electrochemical transistors (OECTs) to classify aqueous electrolytes by ionic composition. Applying periodical gate pulses at different voltage magnitudes, we extracted a reduced number of nonredundant descriptors from the rich drain-current dynamics, which provide enough information to cluster electrochemical data by principal component analysis between Ca2+-, K+-, and Na+-rich electrolytes. With six current values obtained at the appropriate time domain of the device charge/discharge transient, one can identify the cationic identity of a locally probed transient current with only a single micrometric device. Applied to OECT-based neural sensors, this analysis demonstrates the capability for a single nonselective device to retrieve the rich ionic identity of neural activity at the scale of each neuron individually when learning algorithms are applied to the device physics. Full article
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16 pages, 5074 KB  
Article
Chlorine Adsorption on TiO2(110)/Water Interface: Nonadiabatic Molecular Dynamics Simulations for Photocatalytic Water Splitting
by Yin-Pai Lin, Dmitry Bocharov, Inta Isakoviča, Vladimir Pankratov, Aleksandr A. Popov, Anatoli I. Popov and Sergei Piskunov
Electron. Mater. 2023, 4(1), 33-48; https://doi.org/10.3390/electronicmat4010004 - 7 Mar 2023
Cited by 6 | Viewed by 2644
Abstract
Chloride is one of the most abundant ions in sea water, which is more available than fresh water. Due to lack of H2O adsorbate states near the valence band maximum (VBM) edge, the difficulty of water dissociation incidents has been reported [...] Read more.
Chloride is one of the most abundant ions in sea water, which is more available than fresh water. Due to lack of H2O adsorbate states near the valence band maximum (VBM) edge, the difficulty of water dissociation incidents has been reported on the rutile TiO2 surface as the excitation energy is around the band gap energy of TiO2. It is interesting whether the extra chloride can be a benefit to the water dissociation or not. In this study, the models of chlorine adatoms placed on the rutile TiO2 (110)/water interface are constructed using ab initio methods. The time-dependent spatial charges, bond-lengths of water molecules, and Hirshfeld charges are calculated by real-time time-dependent density functional theory and the Ehrenfest dynamics theory for investigating the excited state nonadiabatic dynamics of water dissociation. This study presents two photoinduced water-splitting pathways related to chlorine and analyzes the photogenerated hole along the reactions. The first step of water dissociation relies on the localized competition of oxygen charges between the dissociated water and the bridge site of TiO2 for transforming the water into hydroxyl and hydrogen by photoinduced driving force. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials II)
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11 pages, 2211 KB  
Article
Stress-Relaxed AlN-Buffer-Oriented GaN-Nano-Obelisks-Based High-Performance UV Photodetector
by Pargam Vashishtha, Pukhraj Prajapat, Lalit Goswami, Aditya Yadav, Akhilesh Pandey and Govind Gupta
Electron. Mater. 2022, 3(4), 357-367; https://doi.org/10.3390/electronicmat3040029 - 9 Dec 2022
Cited by 27 | Viewed by 3622
Abstract
Epitaxial GaN nanostructures are developed, and the influence of the AlN buffer layer (temperature modulation) on material characteristics and optoelectronic device application is assessed. The AlN buffer layer was grown on a Si (111) substrate at varying temperatures (770–830 °C), followed by GaN [...] Read more.
Epitaxial GaN nanostructures are developed, and the influence of the AlN buffer layer (temperature modulation) on material characteristics and optoelectronic device application is assessed. The AlN buffer layer was grown on a Si (111) substrate at varying temperatures (770–830 °C), followed by GaN growth using plasma-assisted molecular beam epitaxy. The investigation revealed that the comparatively lower temperature AlN buffer layer was responsible for stress and lattice strain relaxation and was realized as the GaN nano-obelisk structures. Contrarily, the increased temperature of the AlN growth led to the formation of GaN nanopyramidal and nanowax/wane structures. These grown GaN/AlN/Si heterostructures were utilized to develop photodetectors in a metal–semiconductor–metal geometry format. The performance of these fabricated optoelectronic devices was examined under ultraviolet illumination (UVA), where the GaN nano-obelisks-based device attained the highest responsivity of 118 AW−1. Under UVA (325 nm) illumination, the designed device exhibited a high detectivity of 1 × 1010 Jones, noise equivalent power of 1 × 10−12 WHz−1/2, and external quantum efficiency of 45,000%. The analysis revealed that the quality of the AlN buffer layer significantly improved the optoelectronic performance of the device. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials II)
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12 pages, 1746 KB  
Article
Lead-Free BiFeO3 Thin Film: Ferroelectric and Pyroelectric Properties
by Mihaela Botea, Cristina Chirila, Georgia Andra Boni, Iuliana Pasuk, Lucian Trupina, Ioana Pintilie, Luminiţa Mirela Hrib, Becherescu Nicu and Lucian Pintilie
Electron. Mater. 2022, 3(2), 173-184; https://doi.org/10.3390/electronicmat3020015 - 1 Apr 2022
Cited by 8 | Viewed by 5691
Abstract
The ferroelectric and pyroelectric properties of bismuth ferrite (BFO) epitaxial thin film have been investigated. The ferroelectric epitaxial thin layer has been deposited on strontium titanate (STO) (001) substrate by pulsed laser deposition, in a capacitor geometry using as top and bottom electrode [...] Read more.
The ferroelectric and pyroelectric properties of bismuth ferrite (BFO) epitaxial thin film have been investigated. The ferroelectric epitaxial thin layer has been deposited on strontium titanate (STO) (001) substrate by pulsed laser deposition, in a capacitor geometry using as top and bottom electrode a conductive oxide of strontium ruthenate (SRO). The structural characterizations performed by X-ray diffraction and atomic force microscopy demonstrate the epitaxial character of the ferroelectric thin film. The macroscopic ferroelectric characterization of BFO revealed a rectangular shape of a polarization-voltage loop with a remnant polarization of 30 μC/c m2 and a coercive electric field of 633 KV/cm at room temperature. Due to low leakage current, the BFO capacitor structure could be totally pooled despite large coercive fields. A strong variation of polarization is obtained in 80–400 K range which determines a large pyroelectric coefficient of about 10−4 C/m2 K deduced both by an indirect and also by a direct method. Full article
(This article belongs to the Special Issue Electronic Processes in Ferroelectrics)
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12 pages, 3173 KB  
Article
p-Type Iodine-Doping of Cu3N and Its Conversion to γ-CuI for the Fabrication of γ-CuI/Cu3N p-n Heterojunctions
by Argyris Tilemachou, Matthew Zervos, Andreas Othonos, Theodoros Pavloudis and Joseph Kioseoglou
Electron. Mater. 2022, 3(1), 15-26; https://doi.org/10.3390/electronicmat3010002 - 10 Jan 2022
Cited by 12 | Viewed by 4700
Abstract
Cu3N with a cubic crystal structure is obtained in this paper by the sputtering of Cu under N2 followed by annealing under NH3: H2 at 400 °C, after which it was doped with iodine at room temperature [...] Read more.
Cu3N with a cubic crystal structure is obtained in this paper by the sputtering of Cu under N2 followed by annealing under NH3: H2 at 400 °C, after which it was doped with iodine at room temperature resulting into p-type Cu3N with hole densities between 1016 and 1017 cm−3. The Cu3N exhibited distinct maxima in differential transmission at ~2.01 eV and 1.87 eV as shown by ultrafast pump-probe spectroscopy, corresponding to the M and R direct energy band gaps in excellent agreement with density functional theory calculations, suggesting that the band gap is clean and free of mid-gap states. The Cu3N was gradually converted into optically transparent γ-CuI that had a hole density of 4 × 1017 cm−3, mobility of 12 cm2/Vs and room temperature photoluminescence at 3.1 eV corresponding to its direct energy band gap. We describe the fabrication and properties of γ-CuI/TiO2/Cu3N and γ-CuI/Cu3N p-n heterojunctions that exhibited rectifying current-voltage characteristics, but no photogenerated current attributed to indirect recombination via shallow states in Cu3N and/or deep states in the γ-CuI consistent with the short (ps) lifetimes of the photoexcited electrons-holes determined from transient absorption–transmission spectroscopy. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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8 pages, 2477 KB  
Article
Self-Absorption Analysis of Perovskite-Based Luminescent Solar Concentrators
by Yujian Sun, Yongcao Zhang, Yuxin Li and Yilin Li
Electron. Mater. 2021, 2(4), 545-552; https://doi.org/10.3390/electronicmat2040039 - 10 Dec 2021
Viewed by 3706
Abstract
Luminescent solar concentrators (LSCs) are considered promising in their application as building-integrated photovoltaics (BIPVs). However, they suffer from low performance, especially in large-area devices. One of the key issues is the self-absorption of the luminophores. In this report, we focus on the study [...] Read more.
Luminescent solar concentrators (LSCs) are considered promising in their application as building-integrated photovoltaics (BIPVs). However, they suffer from low performance, especially in large-area devices. One of the key issues is the self-absorption of the luminophores. In this report, we focus on the study of self-absorption in perovskite-based LSCs. Perovskite nanocrystals (NCs) are emerging luminophores for LSCs. Studying the self-absorption of perovskite NCs is beneficial to understanding fundamental photon transport properties in perovskite-based LSCs. We analyzed and quantified self-absorption properties of perovskite NCs in an LSC with the dimensions of 6 in × 6 in × 1/4 in (152.4 mm × 152.4 mm × 6.35 mm) using three approaches (i.e., limited illumination, laser excitation, and regional measurements). The results showed that a significant number of self-absorption events occurred within a distance of 2 in (50.8 mm), and the photo surface escape due to the repeated self-absorption was the dominant energy loss mechanism. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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9 pages, 916 KB  
Article
Batteryless Electronic System Printed on Glass Substrate
by Peter Andersson Ersman, Jessica Åhlin, David Westerberg, Anurak Sawatdee, Patrik Arvén and Mikael Ludvigsson
Electron. Mater. 2021, 2(4), 527-535; https://doi.org/10.3390/electronicmat2040037 - 3 Nov 2021
Cited by 3 | Viewed by 4600
Abstract
Batteryless hybrid printed electronic systems manufactured on glass substrates are reported. The electronic system contains a sensor capable of detecting water, an electrochromic display, conductors, a silicon chip providing the power supply through energy harvesting of electromagnetic radiation, and a silicon-based microcontroller responsible [...] Read more.
Batteryless hybrid printed electronic systems manufactured on glass substrates are reported. The electronic system contains a sensor capable of detecting water, an electrochromic display, conductors, a silicon chip providing the power supply through energy harvesting of electromagnetic radiation, and a silicon-based microcontroller responsible for monitoring the sensor status and the subsequent update of the corresponding display segment. The silicon-based components were assembled on the glass substrate by using a pick and place equipment, while the remainder of the system was manufactured by screen printing. Many printed electronic components, often relying on organic materials, are sensitive to variations in environmental conditions, and the reported system paves the way for the creation of electronic sensor platforms on glass substrates for utilization in see-through applications in harsh conditions. Additionally, this generic hybrid printed electronic sensor system also demonstrates the ability to enable autonomous operation through energy harvesting in future smart window applications. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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12 pages, 5422 KB  
Article
Structural and Electronic Properties of Small Perovskite Nanoparticles of the Form ABX3 (A = MA, DEA, FA, GA, B = Pb, Sn, X = Cl, Br, I)
by Christos S. Garoufalis, Iosif Galanakis, Zaiping Zeng, David B. Hayrapetyan and Sotirios Baskoutas
Electron. Mater. 2021, 2(3), 382-393; https://doi.org/10.3390/electronicmat2030026 - 10 Aug 2021
Cited by 9 | Viewed by 5309
Abstract
Using a combination of first principles and semiempirical calculation, we explore the structural, electronic, and optical properties of a wide range of perovskite (ABX3) nanoparticle of different size and composition. The variations of the BX3 backbone [...] Read more.
Using a combination of first principles and semiempirical calculation, we explore the structural, electronic, and optical properties of a wide range of perovskite (ABX3) nanoparticle of different size and composition. The variations of the BX3 backbone structure considered include all possible combinations of the cations B=Pb,Sn and the anions X=Cl,Br,I, while the interstitial cation A is either methylamonium (MA), or formamidinium (FA), or guanidine amine (GA), or dimethylamine (DEA). Our results indicate that the orientational disorder of the A moieties may affect the structural and electronic properties of the NPs while the optical properties exhibit a clear dependence on the NPs’ size and the types of B cations and X anions, but they are quite insensitive to the type of A cation. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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26 pages, 8670 KB  
Article
Impact of the Ferroelectric Stack Lamination in Si Doped Hafnium Oxide (HSO) and Hafnium Zirconium Oxide (HZO) Based FeFETs: Toward High-Density Multi-Level Cell and Synaptic Storage
by Tarek Ali, Kati Kühnel, Ricardo Olivo, David Lehninger, Franz Müller, Maximilian Lederer, Matthias Rudolph, Sebastian Oehler, Konstantin Mertens, Raik Hoffmann, Katrin Zimmermann, Philipp Schramm, Joachim Metzger, Robert Binder, Malte Czernohorsky, Thomas Kämpfe, Konrad Seidel, Johannes Müller, Jan Van Houdt and Lukas M. Eng
Electron. Mater. 2021, 2(3), 344-369; https://doi.org/10.3390/electronicmat2030024 - 4 Aug 2021
Cited by 13 | Viewed by 6549
Abstract
A multi-level cell (MLC) operation as a 1–3 bit/cell of the FeFET emerging memory is reported by utilizing optimized Si doped hafnium oxide (HSO) and hafnium zirconium oxide (HZO) based on ferroelectric laminates. An alumina interlayer was used to achieve the thickness independent [...] Read more.
A multi-level cell (MLC) operation as a 1–3 bit/cell of the FeFET emerging memory is reported by utilizing optimized Si doped hafnium oxide (HSO) and hafnium zirconium oxide (HZO) based on ferroelectric laminates. An alumina interlayer was used to achieve the thickness independent of the HSO and HZO-based stack with optimal ferroelectric properties. Various split thicknesses of the HSO and HZO were explored with lamination to increase the FeFET maximum memory window (MW) for a practical MLC operation. A higher MW occurred as the ferroelectric stack thickness increased with lamination. The maximum MW (3.5 V) was obtained for the HZO-based laminate; the FeFETs demonstrated a switching speed (300 ns), 10 years MLC retention, and 104 MLC endurance. The transition from instant switching to increased MLC levels was realized by ferroelectric lamination. This indicated an increased film granularity and a reduced variability through the interruption of ferroelectric columnar grains. The 2–3 bit/cell MLC levels and maximum MW were studied in terms of the size-dependent variability to indicate the impact of the ferroelectric area scaling. The impact of an alumina interlayer on the ferroelectric phase is outlined for HSO in comparison to the HZO material. For the same ferroelectric stack thickness with lamination, a lower maximum MW, and a pronounced wakeup effect was observed in HSO laminate compared to the HZO laminate. Both wakeup effect and charge trapping were studied in the context of an MLC operation. The merits of ferroelectric stack lamination are considered for an optimal FeFET-based synaptic device operation. The impact of the pulsing scheme was studied to modulate the FeFET current to mimic the synaptic weight update in long-term synaptic potentiation/depression. Full article
(This article belongs to the Special Issue Electronic Processes in Ferroelectrics)
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21 pages, 3678 KB  
Article
In-Situ Characterisation of Charge Transport in Organic Light-Emitting Diode by Impedance Spectroscopy
by Pavel Chulkin
Electron. Mater. 2021, 2(2), 253-273; https://doi.org/10.3390/electronicmat2020018 - 8 Jun 2021
Cited by 2 | Viewed by 4710
Abstract
The article demonstrates an original, non-destructive technique that could be used to in situ monitor charge transport in organic light-emitting diodes. Impedance spectroscopy was successfully applied to determine an OLED’s charge carrier mobility and average charge density in the hole- and electron-transport layer [...] Read more.
The article demonstrates an original, non-destructive technique that could be used to in situ monitor charge transport in organic light-emitting diodes. Impedance spectroscopy was successfully applied to determine an OLED’s charge carrier mobility and average charge density in the hole- and electron-transport layer in a range of applied voltages. The fabricated devices were composed of two commercially available materials: NPB (N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine) and TPBi (2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) as hole- and electron-transport layers, respectively. By varying the thicknesses of the hole-transport layer (HTL) and the electron-transport layer (ETL), correlations between layer thickness and both charge carrier mobility and charge density were observed. A possibility of using the revealed dependencies to predict diode current–voltage characteristics in a wide range of applied voltage has been demonstrated. The technique based on a detailed analysis of charge carrier mobilities and densities is useful for choosing the appropriate transport layer thicknesses based on an investigation of a reference set of samples. An important feature of the work is its impact on the development of fundamental research methods that involve AC frequency response analysis by providing essential methodology on data processing. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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20 pages, 34459 KB  
Article
Porous Polymer Gel Electrolytes Influence Lithium Transference Number and Cycling in Lithium-Ion Batteries
by Buket Boz, Hunter O. Ford, Alberto Salvadori and Jennifer L. Schaefer
Electron. Mater. 2021, 2(2), 154-173; https://doi.org/10.3390/electronicmat2020013 - 27 May 2021
Cited by 10 | Viewed by 6699
Abstract
To improve the energy density of lithium-ion batteries, the development of advanced electrolytes with enhanced transport properties is highly important. Here, we show that by confining the conventional electrolyte (1 M LiPF6 in EC-DEC) in a microporous polymer network, the cation transference [...] Read more.
To improve the energy density of lithium-ion batteries, the development of advanced electrolytes with enhanced transport properties is highly important. Here, we show that by confining the conventional electrolyte (1 M LiPF6 in EC-DEC) in a microporous polymer network, the cation transference number increases to 0.79 while maintaining an ionic conductivity on the order of 103 S cm−1. By comparison, a non-porous, condensed polymer electrolyte of the same chemistry has a lower transference number and conductivity, of 0.65 and 7.6 × 10−4 S cm−1, respectively. Within Li-metal/LiFePO4 cells, the improved transport properties of the porous polymer electrolyte enable substantial performance enhancements compared to a commercial separator in terms of rate capability, capacity retention, active material utilization, and efficiency. These results highlight the importance of polymer electrolyte structure–performance property relationships and help guide the future engineering of better materials. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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12 pages, 3516 KB  
Article
Pyrimidine-Based Push–Pull Systems with a New Anchoring Amide Group for Dye-Sensitized Solar Cells
by Egor V. Verbitskiy, Alexander S. Steparuk, Ekaterina F. Zhilina, Viktor V. Emets, Vitaly A. Grinberg, Ekaterina V. Krivogina, Sergey A. Kozyukhin, Ekaterina V. Belova, Petr I. Lazarenko, Gennady L. Rusinov, Alexey R. Tameev, Jean Michel Nunzi and Valery N. Charushin
Electron. Mater. 2021, 2(2), 142-153; https://doi.org/10.3390/electronicmat2020012 - 26 May 2021
Cited by 15 | Viewed by 3994
Abstract
New donor–π–acceptor pyrimidine-based dyes comprising an amide moiety as an anchoring group have been designed. The dyes were synthesized by sequential procedures based on the microwave-assisted Suzuki cross-coupling and bromination reactions. The influence of the dye structure and length of π-linker on the [...] Read more.
New donor–π–acceptor pyrimidine-based dyes comprising an amide moiety as an anchoring group have been designed. The dyes were synthesized by sequential procedures based on the microwave-assisted Suzuki cross-coupling and bromination reactions. The influence of the dye structure and length of π-linker on the photophysical and electrochemical properties and on the photovoltaic effectiveness of dye-sensitized solar cells was investigated. An increase in efficiency with a decrease in the length of π-linker was revealed. The D1 dye with only one 2,5-thienylene-linker provided the highest power conversion efficiency among the fabricated dye sensitized solar cells. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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11 pages, 2114 KB  
Article
Towards Sustainable Crossbar Artificial Synapses with Zinc-Tin Oxide
by Carlos Silva, Jorge Martins, Jonas Deuermeier, Maria Elias Pereira, Ana Rovisco, Pedro Barquinha, João Goes, Rodrigo Martins, Elvira Fortunato and Asal Kiazadeh
Electron. Mater. 2021, 2(2), 105-115; https://doi.org/10.3390/electronicmat2020009 - 16 Apr 2021
Cited by 7 | Viewed by 4465
Abstract
In this article, characterization of fully patterned zinc-tin oxide (ZTO)-based memristive devices with feature sizes as small as 25 µm2 is presented. The devices are patterned via lift-off with a platinum bottom contact and a gold-titanium top contact. An on/off ratio of [...] Read more.
In this article, characterization of fully patterned zinc-tin oxide (ZTO)-based memristive devices with feature sizes as small as 25 µm2 is presented. The devices are patterned via lift-off with a platinum bottom contact and a gold-titanium top contact. An on/off ratio of more than two orders of magnitude is obtained without the need for electroforming processes. Set operation is a current controlled process, whereas the reset is voltage dependent. The temperature dependency of the electrical characteristics reveals a bulk-dominated conduction mechanism for high resistance states. However, the charge transport at low resistance state is consistent with Schottky emission. Synaptic properties such as potentiation and depression cycles, with progressive increases and decreases in the conductance value under 50 successive pulses, are shown. This validates the potential use of ZTO memristive devices for a sustainable and energy-efficient brain-inspired deep neural network computation. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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12 pages, 1497 KB  
Article
Solution-Processed Organic and ZnO Field-Effect Transistors in Complementary Circuits
by John Barron, Alec Pickett, James Glaser and Suchismita Guha
Electron. Mater. 2021, 2(2), 60-71; https://doi.org/10.3390/electronicmat2020006 - 30 Mar 2021
Cited by 4 | Viewed by 4224
Abstract
The use of high κ dielectrics lowers the operating voltage in organic field-effect transistors (FETs). Polymer ferroelectrics open the path not just for high κ values but allow processing of the dielectric films via electrical poling. Poled ferroelectric dielectrics in p-type organic FETs [...] Read more.
The use of high κ dielectrics lowers the operating voltage in organic field-effect transistors (FETs). Polymer ferroelectrics open the path not just for high κ values but allow processing of the dielectric films via electrical poling. Poled ferroelectric dielectrics in p-type organic FETs was seen to improve carrier mobility and reduce leakage current when compared to unpoled devices using the same dielectric. For n-type FETs, solution-processed ZnO films provide a viable low-cost option. UV–ozone-treated ZnO films was seen to improve the FET performance due to the filling of oxygen vacancies. P-type FETs were fabricated using the ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) as the dielectric along with a donor–acceptor polymer based on diketopyrrolopyrrole (DPP-DTT) as the semiconductor layer. The DPP-DTT FETs yield carrier mobilities upwards of 0.4 cm2/Vs and high on/off ratios when the PVDF-TrFE layer is electrically poled. For n-type FETs, UV–ozone-treated sol–gel ZnO films on SiO2 yield carrier mobilities of 10−2 cm2/Vs. DPP-DTT-based p- and ZnO-based n-type FETs were used in a complementary voltage inverter circuit, showing promising characteristic gain. A basic inverter model was used to simulate the inverter characteristics, using parameters from the individual FET characteristics. Full article
(This article belongs to the Special Issue Feature Papers of Electronic Materials)
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11 pages, 3379 KB  
Article
Synthesis and Characterization of Aero-Eutectic Graphite Obtained by Solidification and Its Application in Energy Storage: Cathodes for Lithium Oxygen Batteries
by Ricardo Walter Gregorutti, Alvaro Yamil Tesio, Juan Luis Gómez-Cámer and Alicia Norma Roviglione
Electron. Mater. 2020, 1(1), 17-27; https://doi.org/10.3390/electronicmat1010003 - 3 Sep 2020
Cited by 2 | Viewed by 3616
Abstract
Aero-eutectic graphite can be defined as a new light material with hierarchically structured porosity. It is obtained from the solidification of gray cast irons, followed by the dissolution of the ferrous matrix by an acidic sequence. The result is a continuous and interconnected [...] Read more.
Aero-eutectic graphite can be defined as a new light material with hierarchically structured porosity. It is obtained from the solidification of gray cast irons, followed by the dissolution of the ferrous matrix by an acidic sequence. The result is a continuous and interconnected network of graphite sheets with varied dimensions randomly oriented. X-ray diffraction characterization has revealed graphite crystallographic planes (002), (100), (101), (102) and (004), while the surface area measured by BET and Langmuir methods has been determined in the order of 90 m2 g−1 and 336 m2 g−1, respectively. The process of obtaining eutectic aero-graphite also allows the deposit of Cu nanofilms and TiC particles. Aero-eutectic graphite has been tested as cathode in Li–O2 batteries as it has been prepared, without the addition of binders or conductive carbons, showing an appropriate contact with the electrolyte, so that the oxygen reduction and evolution reactions may develop satisfactorily. In the discharge-charge galvanostatic tests, the battery accomplishes 20 complete cycles with area capacity limited to 1.2 mAh cm−2. Full article
(This article belongs to the Special Issue Advanced Design and Synthesis of Electrode Materials)
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