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Persistent near-infrared photoconductivity of ZnO nanoparticles based on plasmonic hot charge carriers (2022)
Journal Article
Ibrahem, M. A., Verrelli, E., Cheng, F., Adawi, A. M., Bouillard, J. S. G., & O'Neill, M. (2022). Persistent near-infrared photoconductivity of ZnO nanoparticles based on plasmonic hot charge carriers. Journal of applied physics, 131(10), Article 103103. https://doi.org/10.1063/5.0079006

We report on the coupling of ZnO nanoparticles with plasmonic gold nanoislands in a solution-processed photodetector, which results in a clear enhancement in the optical absorption and the electrical responsivity of ZnO nanoparticles, to cover the vi... Read More about Persistent near-infrared photoconductivity of ZnO nanoparticles based on plasmonic hot charge carriers.

Percolation threshold enables optical resistive‐memory switching and light‐tuneable synaptic learning in segregated nanocomposites (2019)
Journal Article
Jaafar, A. H., O'Neill, M., Kelly, S. M., Verrelli, E., & Kemp, N. T. (2019). Percolation threshold enables optical resistive‐memory switching and light‐tuneable synaptic learning in segregated nanocomposites. Advanced Electronic Materials, 5(7), Article 1900197. https://doi.org/10.1002/aelm.201900197

An optical memristor where the electrical resistance memory depends on the history of both the current flowing through the device and the irradiance of incident light onto it is demonstrated. It is based on a nanocomposite consisting of functionalize... Read More about Percolation threshold enables optical resistive‐memory switching and light‐tuneable synaptic learning in segregated nanocomposites.

Lyotropic 'hairy' TiO2 nanorods (2018)
Journal Article
Cheng, F., Verrelli, E., Alharthi, F. A., Kelly, S. M., O'Neill, M., Kemp, N. T., Kitney, S. P., Lai, K. T., Mehl, G. H., & Anthopoulos, T. (2019). Lyotropic 'hairy' TiO2 nanorods. Nanoscale advances, 1(1), 254-264. https://doi.org/10.1039/c8na00054a

We report the synthesis of the first stable, solution-processable and photocrosslinkable hybrid organic/inorganic titanium dioxide nanorods as ‘hairy rods’ coated with phosphonate ligands with photoreactive coumarin groups located in a terminal posit... Read More about Lyotropic 'hairy' TiO2 nanorods.

Solution-processable, niobium-doped titanium oxide nanorods for application in low-voltage, large-area electronic devices (2017)
Journal Article
Alharthi, F. A., Cheng, F., Verrelli, E., Kemp, N. T., Lee, A. F., Isaacs, M. A., O’Neill, M., & Kelly, S. M. (2017). Solution-processable, niobium-doped titanium oxide nanorods for application in low-voltage, large-area electronic devices. Journal of Materials Chemistry C, 6(5), 1038-1047. https://doi.org/10.1039/c7tc04197g

We report for the first time the one-step synthesis of solution-processable, highly crystalline, niobiumdoped titanium dioxide (Nb-TiO2) nanorods in the anatase phase by the hydrolytic condensation of Ti(OiPr)4 and niobium(V) ethoxide using oleic aci... Read More about Solution-processable, niobium-doped titanium oxide nanorods for application in low-voltage, large-area electronic devices.

Reversible optical switching memristors with tunable STDP synaptic plasticity: a route to hierarchical control in artificial intelligent systems (2017)
Journal Article
Jaafar, A. H., Gray, R. J., Verrelli, E., O'Neill, M., Kelly, S. M., & Kemp, N. T. (2017). Reversible optical switching memristors with tunable STDP synaptic plasticity: a route to hierarchical control in artificial intelligent systems. Nanoscale, 9(43), 17091-17098. https://doi.org/10.1039/c7nr06138b

© 2017 The Royal Society of Chemistry. Optical control of memristors opens the route to new applications in optoelectronic switching and neuromorphic computing. Motivated by the need for reversible and latched optical switching we report on the devel... Read More about Reversible optical switching memristors with tunable STDP synaptic plasticity: a route to hierarchical control in artificial intelligent systems.

Dual wavelength (ultraviolet and green) photodetectors using solution processed zinc oxide nanoparticles (2017)
Journal Article
O'Neill, M., Ibrahem, M. A., Verrelli, E., Lai, K. T., Kyriakou, G., Lee, A. F., Isaacs, M. A., Cheng, F., & O’Neill, M. (2017). Dual wavelength (ultraviolet and green) photodetectors using solution processed zinc oxide nanoparticles. ACS Applied Materials & Interfaces, 9(42), 36971-36979. https://doi.org/10.1021/acsami.7b08092

Narrow-band photoconductivity with a spectral width of 0.16 eV is obtained from solution-processed colloidal ZnO nanocrystals beneath the band-edge at 2.25 eV. A new model involving electron transfer from deep defects to discrete shallow donors is in... Read More about Dual wavelength (ultraviolet and green) photodetectors using solution processed zinc oxide nanoparticles.

Novel liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties for fluorescent OLEDs (2017)
Journal Article
Hu, G., Kitney, S. P., Kelly, S. M., Harrison, W., & O’Neill, M. (2017). Novel liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties for fluorescent OLEDs. Liquid crystals, 44(11), 1632-1645. https://doi.org/10.1080/02678292.2017.1306633

A novel class of nematic liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties has been synthesised using simple and highly efficient reaction pathways. The electroluminescent colour of these novel oligom... Read More about Novel liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties for fluorescent OLEDs.

Solution-processed bilayer photovoltaic devices with nematic liquid crystals (2013)
Journal Article
AlKhalifah, M. S., Lei, C., Myers, S. A., O’Neill, M., Kitney, S. P., & Kelly, S. M. (2014). Solution-processed bilayer photovoltaic devices with nematic liquid crystals. Liquid crystals, 41(3), 402-417. https://doi.org/10.1080/02678292.2013.834082

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer for... Read More about Solution-processed bilayer photovoltaic devices with nematic liquid crystals.

The influence of the nematic phase on the phase separation of blended organic semiconductors for photovoltaics (2013)
Journal Article
Myers, S. A., Al Kalifah, M. S., Lei, C., O'Neill, M., Kitney, S. P., & Kelly, S. M. (2013). The influence of the nematic phase on the phase separation of blended organic semiconductors for photovoltaics. Solar Energy Materials and Solar Cells, 116, 262-269. https://doi.org/10.1016/j.solmat.2013.05.006

Differential scanning calorimetry in combination with atomic force microscopy is used to examine the phase separation of a blended nematic liquid crystalline electron-donor and crystalline perylene electron-acceptor mixture. Separate domains of donor... Read More about The influence of the nematic phase on the phase separation of blended organic semiconductors for photovoltaics.

Liquid crystalline organic semiconductors: nematic spiro[cyclopentyl-1,9']fluorenes (2011)
Journal Article
Billa, M. R., Kassireddy, K., Haro, M., Al-Kalifah, M. S., Kelly, S. M., Kitney, S. P., & O'Neill, M. (2011). Liquid crystalline organic semiconductors: nematic spiro[cyclopentyl-1,9']fluorenes. Liquid crystals, 38(7), 813-829. https://doi.org/10.1080/02678292.2011.577913

A number of nematic spiro[cyclopentyl-1,9′]fluorene reactive mesogens with polymerisable oxetane or non-conjugated diene end-groups have been successfully synthesised. The melting and clearing points of these new spiro[cyclopentyl-1,9′]fluorenes are... Read More about Liquid crystalline organic semiconductors: nematic spiro[cyclopentyl-1,9']fluorenes.

Ordered materials for organic electronics and photonics (2010)
Journal Article
O’Neill, M., & Kelly, S. M. (2011). Ordered materials for organic electronics and photonics. Advanced materials, 23(5), 566-584. https://doi.org/10.1002/adma.201002884

We present a critical review of semiconducting/light emitting, liquid crystalline materials and their use in electronic and photonic devices such as transistors, photovoltaics, OLEDs and lasers. We report that annealing from the mesophase improves th... Read More about Ordered materials for organic electronics and photonics.

Carbazole nematic liquid crystals (2010)
Journal Article
Bao, W., Billa, M. R., Kassireddy, K., Haro, M., Kelly, M. J., Kitney, S. P., Al Kalifah, M. S., Wei, P., Dong, D., O'Neill, M., & Kelly, S. M. (2010). Carbazole nematic liquid crystals. Liquid crystals, 37(10), 1289-1303. https://doi.org/10.1080/02678292.2010.504862

A number of calamitic 2,7-diary-N-alkyl-substituted carbazoles with an enantiotropic nematic phase have been prepared. Branching of the aliphatic chain attached to the nitrogen atom in the carbazole ring leads to significantly lower liquid crystal tr... Read More about Carbazole nematic liquid crystals.

Optical properties of light-emitting nematic liquid crystals: A joint experimental and theoretical study (2010)
Journal Article
Liedtke, A., O'Neill, M., Kelly, S. M., Kitney, S. P., van Averbeke, B., Boudard, P., Beljonne, D., & Cornil, J. (2010). Optical properties of light-emitting nematic liquid crystals: A joint experimental and theoretical study. Journal of Physical Chemistry B, 114(37), 11975-11982. https://doi.org/10.1021/jp104280w

Semiempirical quantum-chemical calculations are used to simulate the optical properties of a series of green light-emitting nematic liquid crystals containing fluorene, thiophene, or thienothiophene groups with solid-state photoluminescence quantum e... Read More about Optical properties of light-emitting nematic liquid crystals: A joint experimental and theoretical study.

One-step photoembossing for submicrometer surface relief structures in liquid crystal semiconductors (2010)
Journal Article
Liedtke, A., Lei, C., O’Neill, M., Dyer, P. E., Kitney, S. P., & Kelly, S. M. (2010). One-step photoembossing for submicrometer surface relief structures in liquid crystal semiconductors. ACS Nano, 4(6), 3248-3253. https://doi.org/10.1021/nn100012g

We report a new single-step method to directly imprint nanometer-scale structures on photoreactive organic semiconductors. A surface relief grating is spontaneously formed when a light-emitting, liquid crystalline, and semiconducting thin film is irr... Read More about One-step photoembossing for submicrometer surface relief structures in liquid crystal semiconductors.

Grazing incidence X-ray diffraction of a photoaligned nematic semiconductor (2009)
Journal Article
Dröge, S., Khalifah, M. S. A., O'Neill, M., Thomas, H. E., Simmonds, H. S., Macdonald, J. E., Aldred, M. P., Vlachos, P., Kitney, S. P., Löbbert, A., & Kelly, S. M. (2009). Grazing incidence X-ray diffraction of a photoaligned nematic semiconductor. Journal of Physical Chemistry B, 113(1), 49-53. https://doi.org/10.1021/jp803379a

Grazing incidence X-ray diffraction is used to find the thin film morphology of an extended molecule with an irregular alternating fluorene - thiophene structure, which is used to obtain linearly polarized electroluminescence and the photovoltaic eff... Read More about Grazing incidence X-ray diffraction of a photoaligned nematic semiconductor.

A new approach to photoalignment: photo-addition to a self-assembled monolayer (2008)
Journal Article
Dröge, S., O'Neill, M., Löbbert, A., Kitney, S. P., Kelly, S. M., Wei, P., & Dong, D. (2009). A new approach to photoalignment: photo-addition to a self-assembled monolayer. Journal of Materials Chemistry, 19(2), 274-279. https://doi.org/10.1039/b812226a

Photoalignment used to control the orientation of nematic liquid crystals in LCDs usually involves the photochemical modification of the chemical structure of an organic thin film so that an optical and/or steric anisotropy is developed. We now demon... Read More about A new approach to photoalignment: photo-addition to a self-assembled monolayer.

White-light OLEDs using liquid crystal polymer networks (2008)
Journal Article
Liedtke, A., O'Neill, M., Wertmöller, A., Kitney, S. P., & Kelly, S. M. (2008). White-light OLEDs using liquid crystal polymer networks. Chemistry of materials : a publication of the American Chemical Society, 20(11), 3579-3586. https://doi.org/10.1021/cm702925f

We have mixed nematic light-emitting liquid crystals and incorporated them as insoluble cross-linked polymer networks in a liquid crystal white-light organic light-emitting diode (LC-WOLED). The light emission is not voltage-dependent and polarized w... Read More about White-light OLEDs using liquid crystal polymer networks.

Photopolymerization studies of a light-emitting liquid crystal with methacrylate reactive groups for electroluminescence
Presentation / Conference Contribution
Woon, K. L., Liedtke, A., O'Neill, M., Aldred, M. P., Kitney, S. P., Vlachos, P., Bruneau, A., & Kelly, S. M. Photopolymerization studies of a light-emitting liquid crystal with methacrylate reactive groups for electroluminescence. Paper presented at Liquid Crystals XII

Light-emitting reactive mesogens are promising materials for photolithographically processable organic light-emitting diodes (OLEDs). We study the photopolymerization of a fluorene-based mesogen with methacrylate photoreactive groups. We find that th... Read More about Photopolymerization studies of a light-emitting liquid crystal with methacrylate reactive groups for electroluminescence.

Calamatic liquid crystal blends for organic photovoltaics
Presentation / Conference Contribution
Lei, C., Al Khalifah, M. S., O'Neill, M., Aldred, M. P., Kitney, S. P., Vlachos, P., & Kelly, S. M. Calamatic liquid crystal blends for organic photovoltaics. Paper presented at Organic Photovoltaics IX

Four different perylene-based electron-acceptors having similar electron affinities, but different thermotropic phases are blended with nematic liquid crystalline electron-donors with a fluorene-thiophene structure to form single layer photovoltaic d... Read More about Calamatic liquid crystal blends for organic photovoltaics.