Publications by authors named "Theodoros Papadopoulos"

Using photoemission spectroscopy (PES), we have systematically investigated the behavior of polar organic molecule, chloroaluminum phthalocyanine (ClAlPc), adsorbed in the Cl-down configuration on the Ag(111) substrate at low temperature - 195 °C under UV irradiation with a range of different photon fluxes. Judging from the evolution of photoemission spectral line shapes of molecular energy states, we discovered that the Cl atoms are so robustly anchored at Ag(111) that the impinging photons cannot flip the ClAlPc molecules, but instead they crouch them down due to radiation pressure; we observe that the phthalocyanine (Pc) lobes bend down to interact with Ag atoms on the substrate and induce charge transfer from them. As photon flux is increased, radiation pressure on the Pc plane initiates tunneling of the Cl atom through the molecular plane to turn the adsorption configuration of ClAlPc from Cl-down to an upheld Cl-up configuration, elucidating an optomechanical way of manipulating the dipole direction of polar molecules.

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We present a computational approach to model hole transport in an amorphous semiconducting fluorene-triphenylamine copolymer (TFB), which is based on the combination of molecular dynamics to predict the morphology of the oligomeric system and Kinetic Monte Carlo (KMC), parameterized with quantum chemistry calculations, to simulate hole transport. Carrying out a systematic comparison with available experimental results, we discuss the role that different transport parameters play in the KMC simulation and in particular the dynamic nature of positional and energetic disorder on the temperature and electric field dependence of charge mobility. It emerges that a semi-quantitative agreement with experiments is found only when the dynamic nature of the disorder is taken into account.

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Effective interface engineering has been shown to play a vital role in facilitating efficient charge-carrier transport, thus boosting the performance of organic photovoltaic devices. Herein, we employ water-soluble lacunary polyoxometalates (POMs) as multifunctional interlayers between the titanium dioxide (TiO) electron extraction/transport layer and the organic photoactive film to simultaneously enhance the efficiency, lifetime, and photostability of polymer solar cells (PSCs). A significant reduction in the work function (W) of TiO upon POM utilization was observed, with the magnitude being controlled by the negative charge of the anion and the selection of the addenda atom (W or Mo).

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Attosecond electron dynamics in small- and medium-sized molecules, induced by an ultrashort strong optical pulse, is studied computationally for a frozen nuclear geometry. The importance of exchange and correlation effects on the nonequilibrium electron dynamics induced by the interaction of the molecule with the strong optical pulse is analyzed by comparing the solution of the time-dependent Schrödinger equation based on the correlated field-free stationary electronic states computed with the equationof-motion coupled cluster singles and doubles and the complete active space multi-configurational self-consistent field methodologies on one hand, and various functionals in real-time time-dependent density functional theory (TDDFT) on the other. We aim to evaluate the performance of the latter approach, which is very widely used for nonlinear absorption processes and whose computational cost has a more favorable scaling with the system size.

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Purpose: To report an unusual case of multifocal bacterial keratitis that despite success-ful treatment caused chronic ocular hypertension.

Methods: A 67-year-old woman with unilateral multifocal keratitis and no previous ocular pathology was admitted to our hospital. Corneal scrapings and conjunctival samples were obtained for culture and the patient received intensive therapy with fortified vancomycin and tobramycin eye drops.

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Organic and printed electronics technologies require conductors with a work function that is sufficiently low to facilitate the transport of electrons in and out of various optoelectronic devices. We show that surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce the work function of conductors including metals, transparent conductive metal oxides, conducting polymers, and graphene. The reduction arises from physisorption of the neutral polymer, which turns the modified conductors into efficient electron-selective electrodes in organic optoelectronic devices.

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Inappropriate food labeling and unwillingness of food companies to officially register their own gluten-free products in the Greek National Food Intolerance Database (NFID) result in a limited range of processed food products available for persons with celiac disease (CDP). The objective of the study was to evaluate the feasibility of developing a gluten-free food product database based on the assessment of the gluten content in processed foods available for CDP. Gluten was assessed in 41 processed food products available for CDP.

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