Publications
414 results found
Huang Y-T, Nodari D, Furlan F, et al., 2023, Fast Near-Infrared Photodetectors Based on Nontoxic and Solution-Processable AgBiS<sub>2</sub>, SMALL, ISSN: 1613-6810
Henderson C, Luke J, Bicalho I, et al., 2023, Charge transfer complex formation between organic interlayers drives light-soaking in large area perovskite solar cells, Energy and Environmental Science, Vol: 16, Pages: 5891-5903, ISSN: 1754-5692
Light soaking (LS) is a well-known but poorly understood phenomenon in perovskite solar cells (PSCs) which significantly affects device efficiency and stability. LS is greatly reduced in large-area inverted PSCs when a PC61BM electron transport layer (ETL) is replaced with C60, where the ETL is commonly in contact with a thin bathocuproine (BCP) interlayer. Herein, we identify the key molecular origins of this LS effect using a combination of surface photovoltage, ambient photoemission spectroscopy, Raman spectroscopy, integrated with density functional theory simulations. We find that BCP forms a photoinduced charge-transfer (CT) complex with both C60 and PC61BM. The C60/BCP complex accelerates C60 dimer formation, leading to a favourable cascading energetic landscape for electron extraction and reduced recombination loss. In contrast, the PC61BM/BCP complex suppresses PC61BM dimer formation, meaning that PC61BM dimerisation is not the cause of LS. Instead, it is the slow light-induced formation of the PC61BM/BCP CT complex itself, and the new energetic transport levels associated with it, which cause the much slower and stronger LS effect of PC61BM based PSCs. These findings provide key understanding of photoinduced ETL/BCP interactions and their impact on the LS effect in PSCs.
Ding B, Bhosale M, Bennett T, et al., 2023, Reducing undesired solubility of squarephaneic tetraimide for use as an organic battery electrode material, Faraday Discussions, ISSN: 1359-6640
Locally aromatic alkyl-N-substituted squarephaneic tetraimide (SqTI) conjugated macrocycles are four-electron reducible, owing to global aromaticity and presumed global Baird aromaticity of the dianion and tetraanion states, respectively. However, their good solubility inhibits their application as a battery electrode material. By applying sidechain removal as a strategy to reduce SqTI solubility, we report the development of its unsubstituted derivative SqTI-H, which was obtained directly from squarephaneic tetraanhydride by facile treatment with hexamethyldisilazane and MeOH. Compared to alkyl-N-substituted SqTI-Rs, SqTI-H exhibited further improved thermal stability and low neutral state solubility in most common organic solvents, owing to computationally demonstrated hydrogen-bonding capabilities emanating from each imide position on SqTI-H. Reversible solid state electrochemical reduction of SqTI-H to the globally aromatic dianion state was also observed at -1.25 V vs. Fc/Fc+, which could be further reduced in two stages. Preliminary testing of SqTI-H in composite electrodes for lithium-organic half cells uncovered imperfect cycling performance, which may be explained by persistent solubility of reduced states, necessitating further optimisation of electrode fabrication procedures to attain maximum performance.
Nanayakkara MPA, He Q, Ruseckas A, et al., 2023, Tissue Equivalent Curved Organic X-ray Detectors Utilizing High Atomic Number Polythiophene Analogues, ADVANCED SCIENCE
Tang Y, Tan WL, Fei Z, et al., 2023, Different energetics at donor:acceptor interfaces in bilayer and bulk-heterojunction polymer:non-fullerene organic solar cells, Solar RRL, Vol: 7, ISSN: 2367-198X
To understand the limitations placed on the open-circuit voltage of bulk heterojunction (BHJ) organic solar cells, the energy levels of neat donor and acceptor samples are often characterized and applied to study BHJ blends. However, energy levels derived from neat samples may not necessarily reflect those at the donor:acceptor interface in blends. The properties of organic semiconductors are sensitive to microstructural changes, with non-fullerene acceptors (NFAs) in particular known to exhibit different thin-film polymorphs. To investigate the influence of differences in molecular packing in neat and blend films, temperature-dependent current–voltage characteristics are measured for bilayer (BL) and BHJ devices. Herein, the fullerene acceptor PC71BM is compared—whose energy levels are expected to be less sensitive to molecular packing—with the NFA ITIC, paired with the same donor polymer PTB7-Th. It is found that the interfacial energy levels differ for BL and BHJ devices for the PTB7-Th:ITIC system but remain the same for the PTB7-Th:PC71BM system. Furthermore, X-ray scattering measurements identify that ITIC exhibits a different packing mode in neat films and in BHJ blends. Such microstructure-dependent differences between neat and blend samples need to be considered when studying energy losses in NFA BHJ solar cells.
Hu X, Qiao Z, Nodari D, et al., 2023, Remarkable Isomer Effect on the Performance of Fully Non-Fused Non-Fullerene Acceptors in Near-Infrared Organic Photodetectors, ADVANCED OPTICAL MATERIALS, ISSN: 2195-1071
Ferree M, Kosco J, De Castro C, et al., 2023, Unleashing the Potential of Organic Semiconductor Nanoparticles towards CO2 Photoreduction, Catalyst Design Strategies for Photo- and Electrochemical Fuel Synthesis, Publisher: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
Rimmele M, Qiao Z, Panidi J, et al., 2023, A polymer library enables the rapid identification of a highly scalable and efficient donor material for organic solar cells, MATERIALS HORIZONS, Vol: 10, Pages: 4202-4212, ISSN: 2051-6347
Sharma A, AlGhamdi WS, Faber H, et al., 2023, Non-invasive, ultrasensitive detection of glucose in saliva using metal oxide transistors, BIOSENSORS & BIOELECTRONICS, Vol: 237, ISSN: 0956-5663
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- Citations: 1
Ling Z, Nugraha MI, Hadmojo WT, et al., 2023, Over 19% Efficiency in Ternary Organic Solar Cells Enabled by n-Type Dopants, ACS ENERGY LETTERS, Vol: 8, Pages: 4104-4112, ISSN: 2380-8195
Xu W, Hart LJF, Moss B, et al., 2023, Impact of Interface Energetic Alignment and Mobile Ions on Charge Carrier Accumulation and Extraction in p-i-n Perovskite Solar Cells, ADVANCED ENERGY MATERIALS, Vol: 13, ISSN: 1614-6832
Cong S, Chen J, Ding B, et al., 2023, Tunable control of the performance of aqueous-based electrochemical devices by post-polymerization functionalization., Materials horizons, Vol: 10, Pages: 3090-3100, ISSN: 2051-6347
Functionalized polymeric mixed ionic-electronic conductors (PMIECs) are highly desired for the development of electrochemical applications, yet are hindered by the limited conventional synthesis techniques. Here, we propose a "graft-onto-polymer" synthesis strategy by post-polymerization functionalization (GOP-PPF) to prepare a family of PMIECs sharing the same backbone while functionalized with varying ethylene glycol (EG) compositions (two, four, and six EG repeating units). Unlike the typical procedure, GOP-PPF uses a nucleophilic aromatic substitution reaction for the facile and versatile attachment of functional units to a pre-synthesized conjugated-polymer precursor. Importantly, these redox-active PMIECs are investigated as a platform for energy storage devices and organic electrochemical transistors (OECTs) in aqueous media. The ion diffusivity, charge mobility and charge-storage capacity can be significantly improved by optimizing the EG composition. Specifically, g2T2-gBT6 containing the highest EG density gives the highest charge-storage capacity exceeding 180 F g-1 among the polymer series, resulting from the improved ion diffusivity. Moreover, g2T2-gBT4 with four EG repeating units exhibits a superior performance compared to its two analogues in OECTs, associated with a high μC* up to 359 F V-1 cm-1 s-1, owing to the optimal balance between ionic-electronic coupling and charge mobility. Through the GOP-PPF, PMIECs can be tailored to access desirable performance metrics at the molecular level.
He Q, Shaw J, Firdaus Y, et al., 2023, p-Type Conjugated Polymers Containing Electron-Deficient Pentacyclic Azepinedione, MACROMOLECULES, Vol: 56, Pages: 5825-5834, ISSN: 0024-9297
Yan H, Cong S, Daboczi M, et al., 2023, Ionic Density Control of Conjugated Polyelectrolytes via Postpolymerization Modification to Enhance Hole-Blocking Property for Highly Efficient PLEDs with Fast Response Times, ADVANCED OPTICAL MATERIALS, ISSN: 2195-1071
Panidi J, Mazzolini E, Eisner F, et al., 2023, Biorenewable solvents for high-performance organic solar cells, ACS Energy Letters, Vol: 8, Pages: 3038-3047, ISSN: 2380-8195
With the advent of nonfullerene acceptors (NFAs), organic photovoltaic (OPV) devices are now achieving high enough power conversion efficiencies (PCEs) for commercialization. However, these high performances rely on active layers processed from petroleum-based and toxic solvents, which are undesirable for mass manufacturing. Here, we demonstrate the use of biorenewable 2-methyltetrahydrofuran (2MeTHF) and cyclopentyl methyl ether (CPME) solvents to process donor: NFA-based OPVs with no additional additives in the active layer. Furthermore, to reduce the overall carbon footprint of the manufacturing cycle of the OPVs, we use polymeric donors that require a few synthetic steps for their synthesis, namely, PTQ10 and FO6-T, which are blended with the Y-series NFA Y12. High performance was achieved using 2MeTHF as the processing solvent, reaching PCEs of 14.5% and 11.4% for PTQ10:Y12 and FO6-T:Y12 blends, respectively. This work demonstrates the potential of using biorenewable solvents without additives for the processing of OPV active layers, opening the door to large-scale and green manufacturing of organic solar cells.
Jiang Z, Du T, Lin C, et al., 2023, Deciphering the role of hole transport layer HOMO level on the open circuit voltage of perovskite Solar cells, Advanced Materials Interfaces, Vol: 10, ISSN: 2196-7350
With the rapid development of perovskite solar cells, reducing losses in open-circuit voltage (Voc) is a key issue in efforts to further improve device performance. Here it is focused on investigating the correlation between the highest occupied molecular orbital (HOMO) of device hole transport layers (HTLs) and device Voc. To achieve this, structurally similar HTL materials with comparable optical band gaps and doping levels, but distinctly different HOMO levels are employed. Using light-intensity dependent Voc and photoluminescence measurements significant differences in the behavior of devices employing the two HTLs are highlighted. Light-induced increase of quasi-Fermi level splitting (ΔEF) in the perovskite layer results in interfacial quasi-Fermi level bending required to align with the HOMO level of the HTL, resulting in the Voc measured at the contacts being smaller than the ΔEF in the perovskite. It is concluded that minimizing the energetic offset between HTLs and the perovskite active layer is of great importance to reduce non-radiative recombination losses in perovskite solar cells with high Voc values that approach the radiative limit.
Bennett TLR, Marsh AV, Turner JM, et al., 2023, Functionalisation of conjugated macrocycles with type I and II concealed antiaromaticity via cross-coupling reactions, Molecular Systems Design & Engineering, Vol: 8, Pages: 713-720, ISSN: 2058-9689
Conjugated macrocycles can exhibit concealed antiaromaticity; that is, despite not being antiaromatic, under specific circumstances, they can display properties typically observed in antiaromatic molecules due to their formal macrocyclic 4n π-electron system. Paracyclophanetetraene (PCT) and its derivatives are prime examples of macrocycles exhibiting this behaviour. In redox reactions and upon photoexcitation, they have been shown to behave like antiaromatic molecules (requiring type I and II concealed antiaromaticity, respectively), with such phenomena showing potential for use in battery electrode materials and other electronic applications. However, further exploration of PCTs has been hindered by the lack of halogenated molecular building blocks that would permit their integration into larger conjugated molecules by cross-coupling reactions. Here, we present two dibrominated PCTs, obtained as a mixture of regioisomers from a three-step synthesis, and demonstrate their functionalisation via Suzuki cross-coupling reactions. Optical, electrochemical, and theoretical studies reveal that aryl substituents can subtly tune the properties and behaviour of PCT, showing that this is a viable strategy in further exploring this promising class of materials.
Jacoutot P, Scaccabarozzi A, Nodari D, et al., 2023, Enhanced Sub-1 eV detection in organic photodetectors through tuning polymer energetics and microstructure, Science Advances, Vol: 9, Pages: 1-9, ISSN: 2375-2548
One of the key challenges facing organic photodiodes (OPD) is increasing the detection into the IR region. Organic semiconductor polymers provide a platform for tuning the bandgap and optoelectronic response to go beyond the traditional 1000 nm benchmark. In this work, we present a NIR polymer with absorption up to 1500 nm. The polymer-based OPD delivers a high specific detectivity D* of 1.03×1010 Jones (-2 V) at 1200 nm and a dark current Jd of just 2.3×10-6 A cm-2 at -2V. We demonstrate a strong improvement of all OPD metrics in the NIR region compared to previously reported NIR-OPD, due to the enhanced crystallinity and optimized energy alignment which leads to reduced charge recombination. The high D* value in the 1100-1300 nm region is particularly promising for biosensing applications. We demonstrate the OPD as a pulse oximeter under NIR illumination, delivering heart rate and blood oxygen saturation readings in real-time without signal amplification.
Polak DW, Andrews I, Farrow G, et al., 2023, Conjugation-length dependence of regioregular oligo 3-alkyl(thienylene-vinylene)s demonstrates polyene-like behaviour with weak electron-electron correlations, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 25, Pages: 11205-11215, ISSN: 1463-9076
Ding B, Jo I-Y, Yu H, et al., 2023, Enhanced Organic Electrochemical Transistor Performance of Donor-Acceptor Conjugated Polymers Modified with Hybrid Glycol/ Ionic Side Chains by Postpolymerization Modification, CHEMISTRY OF MATERIALS, Vol: 35, Pages: 3290-3299, ISSN: 0897-4756
Marsh AV, Heeney M, 2023, Conjugated polymers based on selenophene building blocks, POLYMER JOURNAL, Vol: 55, Pages: 375-385, ISSN: 0032-3896
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- Citations: 5
Heeney M, Rimmele M, Qiao Z, et al., 2023, Low Synthetic Complexity Donor Polymers, International Conference on Hybrid and Organic Photovoltaics 2023, Publisher: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
Anies F, Furlan F, Qiao Z, et al., 2023, A comparison of <i>para</i>, <i>meta</i>, and <i>ortho</i>-carborane centred non-fullerene acceptors for organic solar cells, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 11, Pages: 3989-3996, ISSN: 2050-7526
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- Citations: 1
Creamer A, Lo Fiego A, Agliano A, et al., 2023, Modular synthesis of semiconducting graft co-polymers to achieve ‘clickable’ fluorescent nanoparticles with long circulation and specific cancer targeting, Advanced Materials, Pages: 1-14, ISSN: 0935-9648
Semiconducting polymer nanoparticles (SPNs) are explored for applications in cancer theranostics because of their high absorption coefficients, photostability, and biocompatibility. However, SPNs are susceptible to aggregation and protein fouling in physiological conditions, which can be detrimental for in vivo applications. Here, a method for achieving colloidally stable and low-fouling SPNs is described by grafting poly(ethylene glycol) (PEG) onto the backbone of the fluorescent semiconducting polymer, poly(9,9′-dioctylfluorene-5-fluoro-2,1,3-benzothiadiazole), in a simple one-step substitution reaction, postpolymerization. Further, by utilizing azide-functionalized PEG, anti-human epidermal growth factor receptor 2 (HER2) antibodies, antibody fragments, or affibodies are site-specifically “clicked” onto the SPN surface, which allows the functionalized SPNs to specifically target HER2-positive cancer cells. In vivo, the PEGylated SPNs are found to have excellent circulation efficiencies in zebrafish embryos for up to seven days postinjection. SPNs functionalized with affibodies are then shown to be able to target HER2 expressing cancer cells in a zebrafish xenograft model. The covalent PEGylated SPN system described herein shows great potential for cancer theranostics.
Anies F, Nugraha MI, Fall A, et al., 2023, In Situ Generation of n-Type Dopants by Thermal Decarboxylation, ADVANCED FUNCTIONAL MATERIALS, Vol: 33, ISSN: 1616-301X
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- Citations: 3
He Q, Basu A, Cha H, et al., 2023, Ultra-Narrowband Near-Infrared Responsive J-Aggregates of Fused Quinoidal Tetracyanoindacenodithiophene, ADVANCED MATERIALS, Vol: 35, ISSN: 0935-9648
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- Citations: 1
Hu X, Basu A, Rimmele M, et al., 2023, N-type polymer semiconductors incorporating heteroannulated benzothiadiazole, POLYMER CHEMISTRY, Vol: 14, Pages: 469-476, ISSN: 1759-9954
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- Citations: 2
Nugraha MI, Ardhi REA, Naphade D, et al., 2023, Boosting electron transport in non-fullerene acceptors using non-chlorinated solvents, Journal of Materials Chemistry C, Vol: 11, Pages: 12941-12948, ISSN: 2050-7526
Chlorinated solvents are commonly used to process organic semiconductor devices but have several negative environmental impacts. The choice of processing solvent significantly affects the layer microstructure and device performance, so replacing chlorinated solvents is non-trivial. Herein, we investigate the microstructural and electron-transporting properties of small-molecule non-fullerene acceptor (NFA) films and transistors processed from various non-chlorinated solvents. We show that the ensuing NFA transistors exhibit improved layer morphology, crystallinity, and electron mobility superior to those processed from chlorinated solvents. Our work highlights using non-chlorinated solvents to optimise charge transport in organic semiconductors and their devices while mitigating adverse environmental effects.
Eder S, Ding B, Thornton DB, et al., 2022, Squarephaneic tetraanhydride: a conjugated square‐shaped cyclophane for the synthesis of porous organic materials, Angewandte Chemie International Edition, Vol: 61, Pages: 1-8, ISSN: 1433-7851
Aromatic carboxylic anhydrides are ubiquitous building blocks in organic materials chemistry and have received considerable attention in the synthesis of organic semiconductors, pigments, and battery electrode materials. Here we extend the family of aromatic carboxylic anhydrides with a unique new member, a conjugated cyclophane with four anhydride groups. The cyclophane is obtained in a three-step synthesis and can be functionalised efficiently, as shown by the conversion into tetraimides and an octacarboxylate. Crystal structures reveal the high degree of porosity achievable with the new building block. Excellent electrochemical properties and reversible reduction to the tetraanions are shown for the imides; NMR and EPR measurements confirm the global aromaticity of the dianions and evidence the global Baird aromaticity of the tetraanions. Considering the short synthesis and unique properties, we expect widespread use of the new building block in the development of organic materials.
Rotas G, Antoniou G, Papagiorgis P, et al., 2022, Doping-induced decomposition of organic semiconductors: a caveat to the use of Lewis acid p-dopants, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 10, Pages: 12751-12764, ISSN: 2050-7526
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- Citations: 3
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