Research

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16 pages, 2666 KiB

Open AccessArticle

Nanocomposites of Fe(II)-Based Metallo-Supramolecular Polymer and a Layered Inorganic–Organic Hybrid for Improved Electrochromic Materials

by Kazuko Fujii, Manas Kumar Bera, Dines Chandra Santra and Masayoshi Higuchi

Polymers 2022, 14(5), 915; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14050915 - 25 Feb 2022

Cited by 5 | Viewed by 2229

Abstract

Fe-based metallo-supramolecular polymer (polyFe), composed of Fe(II) ions and bis(terpyridyl)benzene, is known as a good electrochromic (EC) material. For the first time, to improve the EC properties, we prepared nanocomposites comprising polyFe and a layered inorganic–imidazoline covalently bonded hybrid (LIIm) by simply mixing [...] Read more.

Fe-based metallo-supramolecular polymer (polyFe), composed of Fe(II) ions and bis(terpyridyl)benzene, is known as a good electrochromic (EC) material. For the first time, to improve the EC properties, we prepared nanocomposites comprising polyFe and a layered inorganic–imidazoline covalently bonded hybrid (LIIm) by simply mixing them in methanol and then examined the effect of the nanocomposition on EC properties. The obtained blue/purple-colored composites (polyFe/LIIm composites) were demonstrated by scanning electron microscopy (SEM) to comprise a structure of LIIm nanoparticles coated with amorphous polyFe. Interestingly, X-ray diffraction (XRD) measurements suggested that there was no intercalation of polyFe in the interlayer space of LIIm. Ultraviolet-visible (UV-vis) spectroscopy measurements demonstrated that light absorption close to 600 nm was attributed to metal-to-ligand charge transfer (MLCT) from the Fe(II) ion to the bisterpyridine ligand and was influenced by LIIm in the composites. The composites exhibited a pair of redox waves, assigned to the redox between Fe(II) and Fe(III), in the cyclic voltammograms; moreover, the composites were estimated to be diffusion controlled. Thin composite films demonstrated reversible EC changes, triggered by the redox reaction of the metal. Furthermore, the results show that the nano-scale composition of the metallo-supramolecular polymers with LIIm can effectively improve the memory properties without reducing the contrast in transmittance (ΔT) of 70–76% in EC changes after applying 1.2 V vs. Ag/Ag⁺. The EC properties varied with varying ratios (3/0.1, 0.5, 1, and 5) of the polyFe/LIIm, and the ratio of 3/1 exhibited the longest memory and largest MLCT absorption peak among composites. The results show that the polyFe/LIIm composites are useful EC materials for dimming glass applications, such as smart windows. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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14 pages, 10410 KiB

Open AccessArticle

N-Doped Mesoporous Carbon Prepared from a Polybenzoxazine Precursor for High Performance Supercapacitors

by Periyasamy Thirukumaran, Raji Atchudan, Asrafali Shakila Parveen, Madhappan Santhamoorthy, Vanaraj Ramkumar and Seong-Cheol Kim

Polymers 2021, 13(13), 2048; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13132048 - 22 Jun 2021

Cited by 16 | Viewed by 1915

Abstract

Supercapacitors store energy either by ion adsorption or fast surface redox reactions. The capacitance produced by the former is known as electrochemical double layer capacitance and the latter is known as pseudo-capacitance. Carbon materials are found to be attractive materials for energy storage, [...] Read more.

Supercapacitors store energy either by ion adsorption or fast surface redox reactions. The capacitance produced by the former is known as electrochemical double layer capacitance and the latter is known as pseudo-capacitance. Carbon materials are found to be attractive materials for energy storage, due to their various micro-structures and wide source of availability. Polybenzoxazine (Pbz) is used as a source to produce carbon materials, due to the fact that the obtained carbon will be rich in N and O species for enhanced performance. Moreover, the carbon materials were produced via template-free method. In general, activation temperature plays a main role in altering the porosity of the carbon materials. The main purpose of this study is to find the suitable activation temperature necessary to produce porous carbons with enhanced performance. Considering these points, Pbz is used as a precursor to produce nitrogen-doped porous carbons (NRPCs) without using any template. Three different activation temperatures, namely 700, 800 and 900 °C, are chosen to prepare activated porous carbons; NRPC-700, NRPC-800 and NRPC-900. Hierarchical micro-/ meso-/macropores were developed in the porous carbons with respect to different activation temperatures. PBz source is used to produce carbons containing heteroatoms and an activation process is used to produce carbons with desirable pore structures. The surface morphology, pore structure and binding of heteroatoms to the carbon surface were analyzed in detail. NRPCs produced in this way can be used as supercapacitors. Further, electrodes were developed using these NRPCs and their electrochemical performance including capacitance, specific capacitance, galvanic charge/discharge, impedance, rate capability are analyzed. The obtained results showed that the activation temperature of 900 °C, is suitable to produce NRPC with a specific capacitance of 245 F g⁻¹ at a current density of 0.5 A g⁻¹, that are attributed to high surface area, suitable pore structure and presence of heteroatoms. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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9 pages, 3053 KiB

Open AccessArticle

Thermally Activated Delayed Fluorescence in Commercially Available Materials for Solution-Process Exciplex OLEDs

by Zong-Liang Tseng, Wei-Lun Huang, Tzu-Hung Yeh, You-Xun Xu and Chih-Hsun Chiang

Polymers 2021, 13(10), 1668; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13101668 - 20 May 2021

Cited by 9 | Viewed by 3266

Abstract

Organic light-emitting diodes (OLEDs) have developed rapidly in recent years. Thermally activated delayed fluorescent (TADF) molecules open a path to increase exciton collection efficiency from 25% to 100%, and the solution process provides an alternative technology to achieve lower cost OLEDs more easily. [...] Read more.

Organic light-emitting diodes (OLEDs) have developed rapidly in recent years. Thermally activated delayed fluorescent (TADF) molecules open a path to increase exciton collection efficiency from 25% to 100%, and the solution process provides an alternative technology to achieve lower cost OLEDs more easily. To develop commercial materials as exciplex hosts for high-performance and solution-processed OLEDs, we attempted to use 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine (TAPC), poly(9-vinylcarbazole) (PVK), N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB), and poly(N,N’-bis-4-butylphenyl-N,N’-bisphenyl)benzidine (Poly-TPD) as the donors and 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (POT2T) as the acceptor to obtain the TADF effect. All donors and the acceptor were purchased from chemical suppliers. Our work shows that excellent TADF properties and high-efficiency exciplex OLEDs with low turn-on voltage and high luminance can be achieved with a simple combination of commercial materials. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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10 pages, 3323 KiB

Open AccessArticle

Polymeric Hole Transport Materials for Red CsPbI₃ Perovskite Quantum-Dot Light-Emitting Diodes

by Zong-Liang Tseng, Shih-Hung Lin, Jian-Fu Tang, Yu-Ching Huang, Hsiang-Chih Cheng, Wei-Lun Huang, Yi-Ting Lee and Lung-Chien Chen

Polymers 2021, 13(6), 896; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13060896 - 15 Mar 2021

Cited by 8 | Viewed by 3182

Abstract

In this study, the performances of red CsPbI₃-based all-inorganic perovskite quantum-dot light-emitting diodes (IPQLEDs) employing polymeric crystalline Poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(9-vinycarbazole) (PVK), Poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (Poly-TPD) and 9,9-Bis[4-[(4-ethenylphenyl)methoxy]phenyl]-N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD) as the hole transporting layers (HTLs) have been demonstrated. The purpose of this work is [...] Read more.

In this study, the performances of red CsPbI₃-based all-inorganic perovskite quantum-dot light-emitting diodes (IPQLEDs) employing polymeric crystalline Poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(9-vinycarbazole) (PVK), Poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (Poly-TPD) and 9,9-Bis[4-[(4-ethenylphenyl)methoxy]phenyl]-N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD) as the hole transporting layers (HTLs) have been demonstrated. The purpose of this work is an attempt to promote the development of device structures and hole transporting materials for the CsPbI₃-based IPQLEDs via a comparative study of different HTLs. A full-coverage quantum dot (QD) film without the aggregation can be obtained by coating it with VB-FNPD, and thus, the best external quantum efficiency (EQE) of 7.28% was achieved in the VB-FNPD device. We also reported a standing method to further improve the degree of VB-FNPD polymerization, resulting in the improved device performance, with the EQE of 8.64%. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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13 pages, 6826 KiB

Open AccessArticle

19% Efficient P3CT-Na Based MAPbI₃ Solar Cells with a Simple Double-Filtering Process

by Shou-En Chiang, Qi-Bin Ke, Anjali Chandel, Hsin-Ming Cheng, Yung-Sheng Yen, Ji-Lin Shen and Sheng Hsiung Chang

Polymers 2021, 13(6), 886; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13060886 - 13 Mar 2021

Cited by 13 | Viewed by 4965

Abstract

A high-efficiency inverted-type CH₃NH₃PbI₃ (MAPbI₃) solar cell was fabricated by using a ultrathin poly[3-(4-carboxybutyl)thiophene-2,5-diyl]-Na (P3CT-Na) film as the hole transport layer. The averaged power conversion efficiency (PCE) can be largely increased from 11.72 to 18.92% with [...] Read more.

A high-efficiency inverted-type CH₃NH₃PbI₃ (MAPbI₃) solar cell was fabricated by using a ultrathin poly[3-(4-carboxybutyl)thiophene-2,5-diyl]-Na (P3CT-Na) film as the hole transport layer. The averaged power conversion efficiency (PCE) can be largely increased from 11.72 to 18.92% with a double-filtering process of the P3CT-Na solution mainly due to the increase in short-circuit current density (J_SC) from 19.43 to 23.88 mA/cm², which means that the molecular packing structure of P3CT-Na thin film can influence the formation of the MAPbI₃ thin film and the contact quality at the MAPbI₃/P3CT-Na interface. Zeta potentials, atomic-force microscopic images, absorbance spectra, photoluminescence spectra, X-ray diffraction patterns, and Raman scattering spectra are used to understand the improvement in the J_SC. Besides, the light intensity-dependent and wavelength-dependent photovoltaic performance of the MAPbI₃ solar cells shows that the P3CT-Na thin film is not only used as the hole transport layer but also plays an important role during the formation of a high-quality MAPbI₃ thin film. It is noted that the PCE values of the best P3CT-Na based MAPbI₃ solar cell are higher than 30% in the yellow-to-near infrared wavelength range under low light intensities. On the other hand, it is predicted that the double-filtering method can be readily used to increase the PCE of polymer based solar cells. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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10 pages, 2573 KiB

Open AccessCommunication

Long- and Short-Term Conductance Control of Artificial Polymer Wire Synapses

by Naruki Hagiwara, Shoma Sekizaki, Yuji Kuwahara, Tetsuya Asai and Megumi Akai-Kasaya

Polymers 2021, 13(2), 312; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13020312 - 19 Jan 2021

Cited by 6 | Viewed by 3053

Abstract

Networks in the human brain are extremely complex and sophisticated. The abstract model of the human brain has been used in software development, specifically in artificial intelligence. Despite the remarkable outcomes achieved using artificial intelligence, the approach consumes a huge amount of computational [...] Read more.

Networks in the human brain are extremely complex and sophisticated. The abstract model of the human brain has been used in software development, specifically in artificial intelligence. Despite the remarkable outcomes achieved using artificial intelligence, the approach consumes a huge amount of computational resources. A possible solution to this issue is the development of processing circuits that physically resemble an artificial brain, which can offer low-energy loss and high-speed processing. This study demonstrated the synaptic functions of conductive polymer wires linking arbitrary electrodes in solution. By controlling the conductance of the wires, synaptic functions such as long-term potentiation and short-term plasticity were achieved, which are similar to the manner in which a synapse changes the strength of its connections. This novel organic artificial synapse can be used to construct information-processing circuits by wiring from scratch and learning efficiently in response to external stimuli. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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15 pages, 7379 KiB

Open AccessArticle

Metal Organic Framework-Polyethersulfone Composite Membrane for Iodine Capture

by Po-Hsiang Tang, Pamela Berilyn So, Kueir-Rarn Lee, Yu-Lun Lai, Cheng-Shiuan Lee and Chia-Her Lin

Polymers 2020, 12(10), 2309; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102309 - 09 Oct 2020

Cited by 18 | Viewed by 3379

Abstract

A variety of metal organic frameworks (MOFs) were synthesized and evaluated for their iodine adsorption capacity. Out of the MOFs tested, ZIF-8 showed the most promising result with an iodine vapor uptake of 876.6 mg/g. ZIF-8 was then incorporated into a polymer, polyethersulfone [...] Read more.

A variety of metal organic frameworks (MOFs) were synthesized and evaluated for their iodine adsorption capacity. Out of the MOFs tested, ZIF-8 showed the most promising result with an iodine vapor uptake of 876.6 mg/g. ZIF-8 was then incorporated into a polymer, polyethersulfone (PES), at different proportions to prepare mixed matrix membranes (MMMs), which were then used to perform further iodine adsorption experiments. With a mixing ratio of 40 wt % of ZIF-8, the iodine adsorption capacity reached 1387.6 mg/g, wherein an astounding 60% improvement in adsorption was seen with the MMMs prepared compared to the original ZIF-8 powder. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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11 pages, 3665 KiB

Open AccessArticle

Structure and Doping Optimization of IDT-Based Copolymers for Thermoelectrics

by Tongchao Liu, Dexun Xie, Jinjia Xu and Chengjun Pan

Polymers 2020, 12(7), 1463; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12071463 - 30 Jun 2020

Cited by 4 | Viewed by 3033

Abstract

π-conjugated backbones play a fundamental role in determining the thermoelectric (TE) properties of organic semiconductors. Understanding the relationship between the structure–property–function can help us screen valuable materials. In this study, we designed and synthesized a series of conjugated copolymers (P1, P2 [...] Read more.

π-conjugated backbones play a fundamental role in determining the thermoelectric (TE) properties of organic semiconductors. Understanding the relationship between the structure–property–function can help us screen valuable materials. In this study, we designed and synthesized a series of conjugated copolymers (P1, P2, and P3) based on an indacenodithiophene (IDT) building block. A copolymer (P3) with an alternating donor–acceptor (D-A) structure exhibits a narrower band gap and higher carrier mobility, which may be due to the D-A structure that helps reduce the charge carrier transport obstacles. In the end, its power factor reaches 4.91 μW m⁻¹ K⁻² at room temperature after doping, which is superior to those of non-D-A IDT-based copolymers (P1 and P2). These results indicate that moderate adjustment of the polymer backbone is an effective way to improve the TE properties of copolymers. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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Review

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22 pages, 4696 KiB

Open AccessReview

Understanding the PEDOT:PSS, PTAA and P3CT-X Hole-Transport-Layer-Based Inverted Perovskite Solar Cells

by Qi Bin Ke, Jia-Ren Wu, Chia-Chen Lin and Sheng Hsiung Chang

Polymers 2022, 14(4), 823; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14040823 - 21 Feb 2022

Cited by 17 | Viewed by 9829

Abstract

The power conversion efficiencies (PCEs) of metal-oxide-based regular perovskite solar cells have been higher than 25% for more than 2 years. Up to now, the PCEs of polymer-based inverted perovskite solar cells are widely lower than 23%. PEDOT:PSS thin films, modified PTAA thin [...] Read more.

The power conversion efficiencies (PCEs) of metal-oxide-based regular perovskite solar cells have been higher than 25% for more than 2 years. Up to now, the PCEs of polymer-based inverted perovskite solar cells are widely lower than 23%. PEDOT:PSS thin films, modified PTAA thin films and P3CT thin films are widely used as the hole transport layer or hole modification layer of the highlyefficient inverted perovskite solar cells. Compared with regular perovskite solar cells, polymer-based inverted perovskite solar cells can be fabricated under relatively low temperatures. However, the intrinsic characteristics of carrier transportation in the two types of solar cells are different, which limits the photovoltaic performance of inverted perovskite solar cells. Thanks to the low activation energies for the formation of high-quality perovskite crystalline thin films, it is possible to manipulate the optoelectronic properties by controlling the crystal orientation with the different polymer-modified ITO/glass substrates. To achieve the higher PCE, the effects of polymer-modified ITO/glass substrates on the optoelectronic properties and the formation of perovskite crystalline thin films have to be completely understood simultaneously. Full article

(This article belongs to the Special Issue Applications of Polymers in Energy and Environmental Sciences)

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