Simona Fantacci

• Chemistry
• Senior Researcher at Italian National Research Council

The second-order nonlinear optical (NLO) properties of the known heteroleptic complex [Cu(1,10-phenanthroline)xantphos][PF6] (complex 1) and the related new complexes [Cu(5-NO2-1,10-phenanthroline)xantphos][PF6] and [Cu(5-NO2-1,10-phenanthroline)(dppe)][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane) (complexes 2 and 3) were investigated in solution...

The synthesis and characterization of Pt{1,3-bis(4-phenylpyridin-2-yl)-4,6-difluorobenzene}Cl and Pt{1,3-bis(4-(4-methoxy-2,6-dimethylphenyl)-pyridin-2-yl)-4,6-difluorobenzene}Cl are reported. These new NCN-coordinated Pt(II) complexes are both very highly luminescent in deoxygenated solution in the blue region of the spectrum:...

Reaction of 4‐methylphenylacetylide with the known chlorido platinum(II) complex bearing the cyclometalated 1,3‐bis(pyridin‐2‐yl)‐4,6‐difluoro‐benzene ligand afforded a novel alkynyl platinum(II) complex, 1, that was fully characterized by elemental analysis, NMR and UV‐visible spectroscopies, by photoluminescence measurements, and by computational...

The cooling mechanism of hot carriers (HC) in metal halide perovskites is a topic of debate which gathered huge attention due to its critical role in the performance of perovskite‐based optoelectronics. HC cooling in 2D perovskites is faster than in its 3D counterpart, whereas in 2D/3D perovskites cooling becomes faster with decreasing the thicknes...

Both historic and modern synthetic pigments and dyes used in painting are susceptible to alteration due to their interaction with light, atmospheric moisture, oxygen, and other agents of degradation of the environment and of the painting substrate. Unfortunately, a severe and irreversible alteration process is taking place in many artworks of inval...

Photochromic compounds are employed in implementing neuron surrogates. They will boost the development of neuromorphic engineering in wetware. In this work, the photochromic behaviours of (E)-3,4,6-trichloro-2-(p-diazenil)-phenol (t-DZH) and its conjugated phenoxide base (t-DZ) have been investigated experimentally in three different media: (1) pur...

In this study, oxidative degradation of Orange G (OG) and Eosin Y (EY) dyes with TiO2 as the catalyst was explored in air-equilibrated aqueous dispersions under UV light irradiation. To determine the optimal operating conditions for degradation, various effects were investigated, such as the pH of the dye dispersion, the addition of cationic surfac...

Titanium dioxide (TiO2) has been used in numerous paintings since its creation in the early 1920s. However, due to this relatively recent adoption by the art world, we have limited knowledge about the nature and risk of degradation in museum environments. This study expands on the existing understanding of TiO2 facilitated degradation of linseed oi...

The role of tetraalkylammonium bromide surfactants on the TiO2 photocatalyzed degradation of Alizarin, Purpurin and Bromothymol Blue has been studied in air-equilibrated aqueous medium under UV light irradiation. Alizarin has also been investigated by carrying out the photodegradation in TiO2/surfactant dispersions irradiated by natural solar light...

The electronic and vibrational properties of red lead pigment, the mixed valence lead oxide compound Pb3O4, known as minium, have been studied by means of first principle calculations based on Density Functional Theory (DFT) and Fourier Transform–Infra Red (FT-IR) and Raman spectroscopies. The aim of the present investigation is to validate an inte...

The preparation and characterization of a new platinum(II) complex bearing a N^C^N-cyclometalating ligand and a thiolate coligand, namely 5-mesityl-1,3-di-(2-pyridyl)benzene and 1-phenyl-1H-tetrazole-5-thiolate, is reported. Its structure is determined by X-ray diffraction studies on a single crystal. This new complex exhibits green and red phospho...

Whereas there is an increasing amount of reports on the second-order nonlinear optical (NLO) and luminescence properties of tetradentate [N2O2] Schiff base–zinc complexes, the study of zinc complexes having two bidentate [NO] Schiff-base ligands is relatively unexplored from an NLO point of view. This work puts in evidence that the known chiral bis...

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Two new heteroleptic copper(I) sensitizers bearing 6,6’-dimethyl-2,2’-bipyridine-4,4’-dibenzoic acid, to anchor the dye on the titania surface, and a p-delocalized 2-(R-phenyl)-1H-phenanthro[9,10-d]imidazole (R = NPh2 or OHexyl) ancillary ligand were prepared and well characterized. Their performance as dyes in DSSCs is quite similar to that of the...

Three new perylenetetracarboxy-3,4:9,10-diimides, bearing 2,6-diisopropylphenyl groups at the imide positions and 4-(R-ethynyl)phenoxy moieties (R = 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole (P2), pyrene (P3) or pyrene-CH2OCH2 (P4)) at the four bay positions, were prepared, along with the known related derivative (R = phenyl (P1)), and well chara...

Five new platinum(II) complexes bearing a cyclometallated 5-π-delocalized donor-1,3-di(2-pyridyl)benzene were prepared and fully characterized. Their second-order nonlinear optical (NLO) properties were determined by the Electric-Field Induced Second Harmonic generation (EFISH) technique, working in DMF solution with an incident wavelength of 1907...

The absorption of light gives a pigment its colour and its raison d'être, but it also creates excited states, new molecules with an energy excess that can be dissipated through degradation pathways. Photodegradation processes provoke long‐term, cumulative and irreversible colour changes (fading, darkening, blanching) of which the prediction and pre...

The absorption of light gives a pigment its colour and its raison d'être, but it also creates excited states, new molecules with an energy excess that can be dissipated through degradation pathways. Photodegradation processes provoke long‐term, cumulative and irreversible colour changes (fading, darkening, blanching) of which the prediction and pre...

The effect on the second-order nonlinear optical properties of the nature of the π-delocalized moiety in the position 5 of a 1,3-di(2-pyridyl)benzene cyclometallated to a platinum(II) center was investigated. The influence of the substitution of a double bond with a triple bond as bridge between a triphenylamino group and the cyclometallated phenyl...

Herein, the synthesis of a novel family of squaraines (SQ) and their application in p-type dye-sensitized solar cells (DSSC) is presented. In particular, two sets of SQs were designed. The SQs have been characterized by using a joint theoretical, photophysical and electrochemical approach. Importantly, the presence of different central groups force...

We describe the synthesis, computational analysis, photophysics, electrochemistry and electrochemiluminescence (ECL) of a series of compounds formed of two triphenylamines linked by a fluorene or spirobifluorene bridge. The phenylamine moieties were modified at the para-position of the two external rings by electron-withdrawing or electron-donating...

The synthesis and characterization of three 5-π-delocalized-donor-1,3-di(2-pyridyl)benzenes is reported along with that of their related cyclometallated platinum(ii) complexes and N,N-dimethylated iodide salts. The second-order nonlinear optical (NLO) properties of all the compounds have been determined by the Electric Field Induced Second Harmonic...

Charge transport materials (CTMs) are traditionally inorganic semiconductors or metals. However, over the past few decades, new classes of solution-processable CTMs have evolved alongside new concepts for fabricating electronic devices at low cost and with exceptional properties. The vast majority of these novel materials are organic compounds and...

The synthesis and second-order nonlinear optical (NLO) properties of seven novel fullerene-C-60 derivatives are reported. In these donor bridge acceptor systems, the fullerene unit (acceptor) is connected through a cyclopropane ring to an ethynyl thienyl fragment (bridge) which binds a trimethylsilyl or platinum alkynyl fragment (donor). All deriva...

Chrome Yellows (CY) are a family of synthetic pigments of formula PbCr(1-x)SxO4, used by van Gogh and other nineteenth-century masters, whose photo-degradation threatens the conservation of invaluable works of art. Expe-rimental studies have demonstrated that the darkening of the pigment is provoked by the formation of superficial layers of Cr(III)...

The synthesis and second-order nonlinear optical (NLO) properties of seven novel fullerene-C60 derivatives are reported. In these donor-bridge-acceptor systems, the fullerene unit (acceptor) is connected through a cyclopropane ring to an ethynyl thienyl fragment (bridge) which binds a trimethylsilyl or platinum alkynyl fragment (donor). All derivat...

The effects of alkoxy chain length in triarylamine based donor-acceptor organic dyes are investigated with respect to the electronic and molecular surface structures on the performance of solar cells and the electron lifetime. The dyes were investigated when adsorbed on TiO2 in a configuration that can be used for dye-sensitized solar cells (DSCs)....

The photophysical and photochemical properties of alizarin, a fluorescent organic red dye of the family of the anthraquinones, have been theoretically investigated, focusing our attention on the emission properties in relation to an excited state internal proton transfer from the phenolic hydroxyl group to the carbonylic oxygen. The potential energ...

We provide a unified review of recent work carried out on computational investigations of a large series of Ru(II)-polypyridyl complexes effectively employed as solar cells sensitizers in dye-sensitized solar cells (DSCs). The use of methods rooted into Density Functional Theory (DFT) and its Time-Dependent extension (TDDFF) are demonstrated to be...

We report the design, synthesis and computational investigation of a class of Ru(II)-dyes based on mixed bipyridine ligands for use in dye-sensitized solar cells. These dyes are designed to preserve the optimal anchoring mode of the prototypical N719 sensitizer by three carboxylic groups, yet allowing for tunable optimization of their electronic an...

Dye-sensitized solar cells (DSCs) represent a promising approach to the direct conversion of sunlight to electrical energy at low cost and high efficiency. DSCs are based on a film of anatase TiO2 nanoparticles covered by adsorbed molecular dyes and immersed in a liquid redox electrolyte. Upon photoexcitation of the chemisorbed dye, electrons are i...

Relativistic TDDFT calculations have been performed employing a novel computational approach to evaluate the impact of spin–orbit coupling (SOC) in the optical and photovoltaic properties of panchromatic RuII dyes for dye-sensitized solar cells (DSCs). The employed computational setup accurately reproduces the optical properties of the investigated...

We report a facile synthetic route to obtain functionalized quaterpyridine ligand and its trans-dithiocyanato ruthenium complex, based on a microwave-assisted procedure. The ruthenium complex has been purified using a silica chromatographic column by protecting carboxylic acid groups as iso-butyl ester, which are subsequently hydrolyzed. The highly...

Chemical doping is a powerful method to improve the charge transport and to control the conductivity in organic semiconductors (OSs) for wide range of electronic devices. We demonstrate protic ionic liquids (PILs) as effective p-dopant in both polymeric and small molecule OSs. In particular, we show that PILs promote single electron oxidation, whic...

Appropriate functionalization of the cyclometalated ligand, L, and the choice of the ancillary ligand, X, allows the dipolar second-order nonlinear optical response of luminescent [PtLX] complexes-in which L is an N^C^N-coordinated 1,3-di(2-pyridyl)benzene ligand and X is a monodentate halide or acetylide ligand-to be controlled. The complementary...

Photoinduced electron transfer at low band gap ruthenium based dye/TiO2 has been investigated by means of ultra-fast transient absorption and DFT/TDDFT calculations. We demonstrate that while the charge generation mechanism is triplet mediated upon band gap excitation, as already proven in high band gap dyes such as the well known N3 and N719, when...

We report an exhaustive theoretical and computational investigation of the electronic, optical, redox and acid-base properties, along with the adsorption mode on TiO2, of Black Dye (BD), the prototypical panchromatic dye for solar cell applications. We investigated in detail the variation of the relevant dye properties as a function of the solution...

Theoretical and computational modeling is a powerful tool to investigate and characterize the structural, electronic, and optical properties of the main components of dye-sensitized solar cells (DSCs). In this article we focus on the description of the ground and excited state properties of both standalone and TiO2-adsorbed metallorganic and fully...

Smalt is a blue pigment used by many European artists in mural and easel paintings, mainly in the period from the XV to XVIII century. It is a potassium glass where cobalt is added to the glassy matrix to get the blue hue. The pigment deteriorates with age, changing its colour from an intense blue to a grey-yellowish hue, causing severe problems in...

The second order nonlinear optical (NLO) properties of various simple tris-cyclometallated Ir(iii) complexes bearing 2-phenylpyridine ligands have been investigated by means of the EFISH technique, evidencing how appropriate substitution of the cyclometallated ligands may allow the tuning of the second-order NLO response of this unusual family of 3...

The dipolar and octupolar contributions of the second order nonlinear optical properties of [(4'-(C(6)H(4)-p-D)-2,2':6',2''-terpyridine)-Ru-(4'-(C(6)H(4)-p-A)-2,2':6',2''-terpyridine)]Y(2) heteroleptic complexes (D and A are donor and acceptor groups, respectively), and related free terpyridines and homoleptic complexes, have been obtained by means...

In solid-state dye-sensitized solar cells (ssDSCs), the poor pore filling of the mesoporous semiconductor and the short diffusion length of charge carriers in the hole- transport material (HTM) have limited the mesoscopic titania layer to a thickness of 2-3 μm. To increase the amount of light harvested by ssDSCs, organic dyes with high molar extinc...

A series of new π-conjugated organic dyes (HKK-BTZ1, HKK-BTZ2, HKK-BTZ3 and HKK-BTZ4), comprising triphenylamine (TPA) moieties as the electron donor and benzothiadiazole moieties as the electron acceptor/anchoring groups, was synthesized for the use in dye-sensitized solar cells (DSSCs). TPA units are bridged to benzothiadiazole with single(S), do...

Ruthenium(II) and Iridium(III) polypyridyl complexes have been intensively investigated due to their use in energy conversion and light-emitting devices and materials for non-linear optics. Quantum mechanical computer simulations of molecules and materials have become increasingly popular in the scientific community. Along with experimental investi...

We investigate the spectroscopic signature of oxidized dyes and of their complexes with I– occurring in the oxidation/regeneration process in dye-sensitized solar cells. Following the transient absorption spectroscopy study by Clifford et al. [J. Phys. Chem. C, 2007, 111, 6561–6567], we report a DFT/TDDFT study on the geometrical, electronic, and o...

The spectroscopic properties of indigo, one of the most important natural dyes present in nature, have been investigated by means of DFT and TD-DFT calculations and Raman and IR spectroscopies. The absorption spectra of this dye, in vacuo and in different solvents, have been computed. The formation of aggregates in solvent have been investigated by...

We have investigated the absorption spectrum and the alignment of ground and excited state energies for the prototypical N719 Ru(II) sensitizer adsorbed on an extended TiO2 model by means of high level DFT/TDDFT calculations. The calculated and experimental absorption spectra for the dye on TiO2 are in excellent agreement over the explored energy r...

We report a DFT/TDDFT study on the geometric, electronic and optical properties of [Ru{4′-(4-pyridyl)-2,2′:6′,2"-terpyridine}2]2+. Because of the presence of the basic nitrogen atom on the terminal pyridyl ligands, in solution the complex can exist in three different protonation states depending on the pH, each with markedly different photophysical...

Dye-sensitized solar cells (DSCs) represent a valuable, efficient, and low-cost alternative to conventional semiconductor photovoltaic devices. A deeper understanding of the dye/semiconductor heterointerface and of the dye-sensitized semiconductor/electrolyte interactions are fundamental for further progress in DSC technology. Here we report an ab...

Ab initio calculations of the ground state oxidation potential (GSOP) and excited state oxidation potential (ESOP) are reported for a set of four triphenylamine-based dyes for dye-sensitized solar cell (DSSC) applications, with increasing degree of charge transfer. The performance of DFT in predicting GSOP is evaluated by employing various exchange...

Phenyl-imidazole-based ligands with various substitution patterns have been used as the main ligand for heteroleptic bis-cyclometalated iridium complexes. Two series of complexes have been prepared and their photophysical and electrochemical properties were studied. The phosphorescence emission maxima range from about 490 to 590 nm, that is, from g...

The first example of a heteroarylvinylene π-conjugated quaterpyridine Ru(II) sensitizer (N1044) was synthesized and used in dye-sensitized solar cells; the dye has an effective panchromatic absorption band, covering the entire visible spectrum up to the NIR region, and superior electrochemical characteristics (HOMO/LUMO and bandgap energies) with r...

The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. A...

7-N,N-Dibutylamino-2-azaphenanthrene (L(3)), 8-N,N-dibutylamino-2-azachrysene (L(4)) and related Ir(i) complexes or alkylated salts show high second-order NLO responses, as determined by the EFISH technique and DFT calculations. L(4) is appealing as building block for NLO active materials due to its unexpected large μβ(1.907)value and its very high...

Co-crystallization of p-N(CH(3))(2)C(6)H(4)CHO and E-4-(4-dimethylaminostyryl)-1-methylpyridinium iodide ([DAMS]I) gives a new solid state form (A), characterized by high non-linear-optical (NLO) activity and quite different from the well known [DAMS]I salt (centrosymmetric and therefore inactive). The X-ray structural characterization, although af...

A new class of push–pull spirobifluorene compounds 1–5 has been synthesized. The nonlinear optical (NLO) properties (first and second hyperpolarizability β and γ, respectively)of spirobifluorene derivatives have been investigated forthe first time using electric field induced second harmonic(EFISH) and third harmonic generation (THG) methods. Moreo...

Chemistry is central to addressing topics of interest in the cultural heritage field, offering particular insight into the nature and composition of the original materials, the degradation processes that have occurred over the years, and the attendant physical and chemical changes. On the one hand, the chemical characterization of the constituting...

We report a systematic density functional theory (DFT) computational investigation of Ru(II) sensitizer/TiO2 systems relevant to dye-sensitized solar cells (DSSCs). Focusing on the prototypical N719 and the recently introduced YE05 sensitizers, and considering large slab and cluster models for TiO2, we have systematically studied the influence of t...

[Ir(ppy)(2)(RCOCR'COR)] and [Pt(ppy)(RCOCHCOR)] (ppy = cyclometallated 2-phenylpyridine; R = Me, Ph; R' = H, 2,4-dinitrophenyl) complexes show an unexpected large second order non linear optical response, as evidenced by the EFISH technique, which can be attributed by an SOS-TDDFT investigation mainly to intraligand charge transfer transitions invo...

A DFT-TDDFT investigation on the aluminium complexation of apigenin and luteolin has been carried out. We have focused our attention on these hydroxyflavonoids, which are the main components of weld, one of the earliest natural dyestuff used in art. In particular, weld, upon complexation with Al(iii) forms a highly prized lake which has been widely...

Cyclometalated cationic IrIII complexes with substituted 1,10-phenanthrolines (1, 10-phen), such as [Ir(ppy)2(5-R-1, 10-phen)]Y (ppy = cyclometalated 2-phenylpyridine; R = NO2, H, Me, NMe2; Y- = PF6-, C 12H25SO3-, I-) and [Ir(ppy)2(4-R,7-R-1,10-phen)]Y (R = Me, Ph) are characterized by a significant second-order optical non linearity (measured by t...

We provide a unified view of our recent work on TDDFT calculations on the class of Iridium(III) cyclometallated complexes, of relevance for their extensive use in OLED and LEEC devices. Our results, obtained for vastly different systems, allow us to trace some general conclusions concerning the modeling of these transition metal complexes. The effe...

The absorption and emission properties of the two components of the yellow color extracted from weld (Reseda luteola L.), apigenin and luteolin, have been extensively investigated by means of DFT and TDDFT calculations. Our calculations reproduce the absorption spectra of both flavonoids in good agreement with the experimental data and allow us to...

A simple mononuclear cyclometallated iridium(iii) complex exhibits white photo- and electro- luminescence in the wavelength range from 440 to 800 nm, which originates from a single emitting excited state of mixed character.

Forward from square one: The incorporation of a molecularly engineered original panchromatic squaraine sensitizer in a dye-sensitized solar cell enables the preparation of devices having external quantum efficiencies as high as 4.71 %; an unprecedented result for this class of compounds.

Solid-state dye-sensitized solar cells were fabricated using an organic dye, 2-cyanoacrylic acid-4-(bis-dimethylfluoreneaniline)dithiophene (JK2), which exhibits more than 1 V open-circuit potential (V(oc)). To scrutinize the origin of high voltage in these cells, transient V(oc) decay measurements and density functional theroy calculations of the...

A novel heteroleptic ruthenium complex carrying a heteroaromatic-4,4'-pi-conjugated 2,2'-bipyridine [Ru(II)LL'(NCS)(2)] (L = 4,4'-bis[(E)-2-(3,4-ethylenedioxythien-2-yl)vinyl]-2,2'-bipyridine, L' = 4,4'-(dicarboxylic acid)-2,2'-bipyridine) was synthesized and used in dye-sensitized solar cells, yielding photovoltaic efficiencies of 9.1% under stand...

The structural properties of luteolin, apigenin and of all their possible mono-deprotonated species are studied with ab initio methods in vacuo and in solution. Molecular structures have been optimized by MP2 and DFT using different functionals and basis sets. Harmonic vibrational frequency calculations have been performed on the optimized structur...

We present a theoretical study of the lineup of the LUMO of Ru(II)-polypyridyl (N3 and N719) molecular dyes with the conduction band edge of a TiO(2) anatase nanoparticle. We use density functional theory (DFT) and the Car-Parrinello scheme for efficient optimization of the dye-nanoparticle systems, followed by hybrid B3LYP functional calculations...

[Ir(cyclometallated 4,5-diphenyl-2-methyl-thiazole)2(5-R-1,10-phenanthroline)][PF6] (R=CH3, NO2) complexes were prepared and fully characterized, the structure of the complex with 5-CH3-1,10-phenanthroline being also determined by X-ray diffraction. The emission properties of both complexes have been investigated and their second-order nonlinear op...

The acid–base chemistry of luteolin, a flavonoid with important pharmacological and dyeing properties, and of the related methyl ether derivatives have been investigated by DFT and MP2 methods, testing different computational setups. We calculate the pKa’s of all the possible deprotonation sites, for which no experimental assignment could be achiev...

In this paper structure and electronic properties of luteolin and apigenin and all their possible anionic species have been investigated with DFT and MP2 methods. Molecular geometries have been optimized obtaining for all systems non-planar structures except for the deprotonated species in 4’ position. Potential energy proles as a function of the t...

Dye sensitized solar cells (DSSCs) represent a promising approach to the direct conversion of light into electrical energy at low cost and with high efficiency. In these devices, a dye sensitizer absorbs the solar radiation and transfers the photoexcited electron to a nanostructured TiO2 electrode. We have studied the electronic structure of differ...

Highly phosphorescent blue-light-emitting anionic iridium complexes (C4H9)4N[Ir(2-phenylpyridine)2(CN)2] (1), (C4H9)4N[Ir(2-phenyl-4-dimethylaminopyridine)2(CN)2] (2), (C4H9)4N[Ir(2-(2,4-difluorophenyl)-pyridine)2(CN)2] (3), (C4H9)4N[Ir(2-(2,4-difluorophenyl)-4-dimethylaminopyridine)2(CN)2] (4), and (C4H9)4N[Ir(2-(3,5-difluorophenyl)-4-dimethylamin...

J-type aggregation of organic chromophores into inorganic host matrixes provides a useful route toward materials showing strong second-order nonlinear optical (NLO) response. The increased NLO response of J-aggregates is related to the peculiar arrangement of the NLO-phores into the host matrix, which produces the appearance of a narrow and intense...

The luminescence and second order non linear optical (NLO) response of [Ir(ttpy)2(5-R-1,10-phen)][PF6] (ttpy = cyclometallated 3′-(2-pyridil)-2,2′:5′,2″-terthiophene, phen = phenanthroline; R = Me, NO2) and [Ir(pq)2(5-R-1,10-phen)][PF6] (pq = cyclometallated 2-phenylquinoline) have been investigated experimentally in CH2Cl2 solution and compared wi...

We performed fully first principles quantum mechanical calculations of the ground- and excited-state properties of the [cis (NCS)(2)-Ru(Il)-bis(2,2'-bipyridine-4,4'-dicarboxylate)] dye, N719, adsorbed onto a model TiO2 nanoparticle. Our study confirms an indirect electron injection mechanism for Ru(II) dyes on TiO2 and indicates a remarkable effect...

[Ir(ppy)(2)(5-R-1,10-phen)][PF(6)] (ppy = cyclometallated 2-phenylpyridine, phen = phenanthroline, R = H, Me, NMe(2), NO(2)) and [Ir(ppy)(2)(4-R',7-R'-1,10-phen)][PF(6)] (R' = Me, Ph) complexes are characterized by one of the highest second order NLO response (measured by the EFISH technique) reported for a metal complex, mainly due (as suggested b...

The photophysical and electrochemical properties of the novel complexes [Ir(ppy)(2)(5-X-1,10-phen)][PF(6)] (ppy = 2-phenylpyridine, phen = phenanthroline, X = NMe(2), NO(2)), [Ir(pq)(2)(5-X-1,10-phen)][PF(6)] (pq = 2-phenylquinoline, X = H, Me, NMe(2), NO(2)), [Ir(ppy)2(4-Me,7-Me-1,10-phen)][PF(6)], [Ir(ppy)2(5-Me,6-Me-1,10-phen)][PF(6)], [Ir(ppy)(...

We report a combined experimental and theoretical study on the origin of the different open circuit potentials observed in dye-sensitized solar cells using Ru(II)-polypyridyl homoleptic and heteroleptic sensitizers. We have measured the photovoltaic data of different sensitizers and used DFT calculations to analyze the electronic structure of dye-s...

We report time-dependent (TD) and coupled-perturbed (CP) DFT/HF investigations, on the linear and non-linear optical properties of M(II)-complexes of [5-[(4′-dimethylaminophenyl)-ethynyl]-15-[(4″-nitrophenyl)ethynyl]-10,20-diphenylporphyrin], with M=Zn, Cu, Ni. The TD-DFT absorption spectrum is in good agreement with the experimental one, allowing...

The photoluminescence properties of a novel class of cyclometallated Ir(III) complexes of the kind [Ir(ppy) 2 (5-X-1,10-phen)][PF 6 ] (ppy=2-phenylpyridine, phen= phenanthroline, X=H, Me, NMe 2 , NO 2) and [Ir(ppy) 2 (4-X,7-X-1,10-phen)][PF 6 ] (X=Me, Ph) were investigated, evidencing how the nature and number of the phenanthroline substituents tun...

We describe the synthesis, characterization, and photophysics of new cationic Ir(III) complexes for OLED applications. For the [Ir(2,4-difluorophenylpyridine)2(4,4‘-dimethylamino-2,2‘-bipyridine)](PF6), blue-green emission at 463 nm with quantum yield of 85% is obtained. DFT and TDDFT calculations provide assignment of the absorption and emission s...

We present a combined computational strategy for the study of the optical properties of nanoscale systems, using a combination of codes and techniques based on Density Functional Theory (DFT) and its Time Dependent extension (TDDFT). In particular, we describe the use of Car–Parrinello molecular dynamics simulations for the study of nanoscale devic...

A high molar extinction coefficient charge transfer sensitizer tetrabutylammonium [Ru(4,-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(4,4'di-(2-(3,6-dimethoxyphenyl)ethenyl)-2,2'-bipyridine)(NCS)(2)], is developed which upon anchoring onto nanocrystalline TiO2 films exhibit superior power conversion efficiency compared to the standard sensitizer...

Novel organic sensitizers comprising donor, electron-conducting, and anchoring groups were engineered at molecular level and synthesized. The functionalized unsymmetrical organic sensitizers 3-{5-[N,N-bis(9,9-dimethylfluorene-2-yl)phenyl]-thiophene-2-yl}-2-cyano-acrylic acid (JK-1) and 3-{5'-[N,N-bis(9,9-dimethylfluorene-2-yl)phenyl]-2,2'-bisthioph...

We present a combined density functional theory (DFT)/time-dependent density functional theory (TDDFT) study of the geometry, electronic structure, and absorption and emission properties of the tetranuclear "cubane" Cu4I4py4 (py = pyridine) system. The geometry of the singlet ground state and of the two lowest triplet states of the title complex we...

A highly luminescent novel cationic iridium complex [iridium bis(2-phenylpyridine)(4,4'-(dimethylamino)-2,2'-bipyridine)]PF6 was synthesized and characterized using NMR, UV-visible absorption, and emission spectroscopy and electrochemical methods. This complex displays intense photoluminescence maxima in the green-blue region of the visible spectru...

A ruthenium complex trans-[Ru(L)(NCS)2], L = 4,4' ''-di-tert-butyl-4',4' '-bis(carboxylic acid)-2,2':6',2' ':6' ',2' ''-quaterpyridine (N886), was synthesized and characterized by spectroscopic and electrochemical methods. The absorption spectrum of the N886 complex shows metal-to-ligand charge-transfer transitions in the entire visible region and...

The energetics and reaction mechanism of prototypical organometallic reactions have been investigated by combining static and dynamic density functional calculations, based on the Car–Parrinello method. Such an approach allows us to dynamically sample the potential energy surface of the reactive system at finite temperature, providing useful insigh...

We report a theoretical study based on density functional theory (DFT) and time-dependent DFT (TDDFT) calculations on the nature and role of the absorption bands involved in the nonlinear optical response of the complexes [Ru(CF3CO2)3T] (T = T1, T2; T1 = 4'-(C6H4-p-NBu2)-2,2':6',2''-terpyridine, T2 = 4'-(C6H4-p-NMe2)-2,2':6',2''-terpyridine). Geome...