Massimo Cocchi | Consiglio Nazionale delle Ricerche (CNR) (original) (raw)
Papers by Massimo Cocchi
amslaurea.cib.unibo.it
... Antonio Maggiore Dott. Stefano Stagni Correlatore: Dott. ... applicazioni tecnologiche nel ca... more ... Antonio Maggiore Dott. Stefano Stagni Correlatore: Dott. ... applicazioni tecnologiche nel campo dell'opto-elettronica. In particolare l'attenzione è stata rivolta ai complessi di metalli di transizione fotoattivi, viste le numerose applicazioni possibili come assorbitori di luce, sensori ...
New Journal of Chemistry, 2011
... Cedex, France. E-mail: christine.paul@univ-rennes1.fr; Fax: +33 02 23 23 56 37; Tel: +33 02 2... more ... Cedex, France. E-mail: christine.paul@univ-rennes1.fr; Fax: +33 02 23 23 56 37; Tel: +33 02 23 23 63 72. b Institut National des Sciences Appliquées-INSA, 20 Avenue Buttes de Coësme, 35700 Rennes, France. c Consiglio ...
Organic Light-Emitting Diodes (OLEDs), 2013
ABSTRACT This chapter provides an overview on the road map used to tune the colour and efficiency... more ABSTRACT This chapter provides an overview on the road map used to tune the colour and efficiency of organic light emitting devices (OLEDs). A comprehensive introduction to the potential of OLED technology is first provided. Then attention is given on one way to obtain a multi- emission by a single phosphor, making use of platinum(II) complexes as phosphorescent emitters. OLEDs prepared using highly luminescent Pt(II) complexes containing cyclometallating bidentate and terdentate ligands are presented. These complexes with square planar configuration often lead to stacking and formation of luminescent aggregates. A brief description of the nature of these bimolecular exited states is reported. Taking advantage of this behaviour, many types of OLEDs, such as White OLED (WOLED), Near-InfraRed OLED (NIROLED) and Plant Growth OLED (PGOLED), are shown. Such devices fulfil the requirements to become an important part of ‘green photonics’.
Dalton Trans., 2014
The irreversible reaction of methyl triflate with neutral Re(i) tetrazolato complexes of the type... more The irreversible reaction of methyl triflate with neutral Re(i) tetrazolato complexes of the type fac-[Re(diim)(CO)3(L)], where diim is either 1,10-phenanthroline or 2,2'-bipyridine and L is a para substituted 5-aryltetrazolate, yielded the corresponding cationic methylated complexes. While methylation occurred regioselectively at the N4 position of the tetrazole ring, the cationic complexes were found to exist in solution as equilibrating mixtures of linkage isomers, where the Re(i) centre was bound to either the N1 or N2 atom of the tetrazole ring. The existence of these isomers was highlighted both by NMR and X-ray crystallography studies. On the other hand, the two isomers appeared indistinguishable by IR, UV-Vis and luminescence spectroscopy. The prepared cationic complexes are all brightly phosphorescent in fluid and rigid solutions, with emission originating from triplet metal-to-ligand charge transfer excited states. Compared to their neutral precursors, which emit from admixtures of triplet metal-to-ligand and ligand-to-ligand charge transfer states, the methylated complexes exhibit blue-shifted emission characterised by elongated excited state lifetimes and increased quantum yields. The nature of the excited states for both the neutral and the methylated complexes was probed by resonance Raman spectroscopy and with the aid of time-dependent density functional theory calculations. Lastly, both the neutral and the methylated species were used as emitting phosphors in the fabrication of Organic Light Emitting Diodes and Light Emitting Electrochemical Cells.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 29, 2015
The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxid... more The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae⋅HOEt)(L)4 ]2 (Ln=Eu(3+) , Er(3+) , Yb(3+) ; Ae=Na(+) , K(+) , Rb(+) ). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb(3+) and Er(3+) showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes (τobs ≈37-47 μs for Yb(3+) and τobs ≈4-6 μs for Er(3+) ) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu(3+) assemblies show bright red emission and a lumi...
MRS Proceedings, 1997
ABSTRACT In the present contribution a new hole transporting molecule belonging to the triphenyld... more ABSTRACT In the present contribution a new hole transporting molecule belonging to the triphenyldiamine family (N,N'-diphenyl-N,N'-bis(4-metylphenyl)- 1, 1'-biphenyl-4,4'- diamine) in a polycarbonate matrix is studied as the hole transport layer in a two layer device with Alq3 as emitting layer. The dependence of the electrical and emitting behaviour on the doping level is studied and compared with the vacuum deposited diamine layer also interfaced with Alq3
Advanced Materials For Optics and Electronics, 1999
ABSTRACT
Coordination Chemistry Reviews, 2011
Journal of Materials Chemistry C, 2013
ABSTRACT We investigated the nature of the emissive states in newly synthesized cyclometallated P... more ABSTRACT We investigated the nature of the emissive states in newly synthesized cyclometallated Pt complexes containing a chelating 2-pyridyl tetrazolate (2-PTZ) ligand, namely Pt(ppy)(2-PTZ), and Pt(F2ppy)(2-PTZ) as a solid-state phosphor, by examining their structural properties versus their phosphorescence (PH) and electroluminescence (EL) characteristics. It is found that the observed tuning of both PH and EL spectra, their red shift and shortening decay with increasing concentration in the complex blends are due to the competition between three emissive states: monomer, excimer and dimer. The pure dimer emission appeared in neat films, reaching a high PH quantum yield of about 75% and external EL efficiency approaching 10% for the OLED based on the neat Pt(F2ppy)(2-PTZ) complex film as an emitting layer (EML). X-ray diffraction proved the high structural order of the latter thin film. These findings have a direct impact on the design of a new OLED generation based on single phosphor multi-emission controlled by the structural order degree of the EML.
amslaurea.cib.unibo.it
... Antonio Maggiore Dott. Stefano Stagni Correlatore: Dott. ... applicazioni tecnologiche nel ca... more ... Antonio Maggiore Dott. Stefano Stagni Correlatore: Dott. ... applicazioni tecnologiche nel campo dell'opto-elettronica. In particolare l'attenzione è stata rivolta ai complessi di metalli di transizione fotoattivi, viste le numerose applicazioni possibili come assorbitori di luce, sensori ...
New Journal of Chemistry, 2011
... Cedex, France. E-mail: christine.paul@univ-rennes1.fr; Fax: +33 02 23 23 56 37; Tel: +33 02 2... more ... Cedex, France. E-mail: christine.paul@univ-rennes1.fr; Fax: +33 02 23 23 56 37; Tel: +33 02 23 23 63 72. b Institut National des Sciences Appliquées-INSA, 20 Avenue Buttes de Coësme, 35700 Rennes, France. c Consiglio ...
Organic Light-Emitting Diodes (OLEDs), 2013
ABSTRACT This chapter provides an overview on the road map used to tune the colour and efficiency... more ABSTRACT This chapter provides an overview on the road map used to tune the colour and efficiency of organic light emitting devices (OLEDs). A comprehensive introduction to the potential of OLED technology is first provided. Then attention is given on one way to obtain a multi- emission by a single phosphor, making use of platinum(II) complexes as phosphorescent emitters. OLEDs prepared using highly luminescent Pt(II) complexes containing cyclometallating bidentate and terdentate ligands are presented. These complexes with square planar configuration often lead to stacking and formation of luminescent aggregates. A brief description of the nature of these bimolecular exited states is reported. Taking advantage of this behaviour, many types of OLEDs, such as White OLED (WOLED), Near-InfraRed OLED (NIROLED) and Plant Growth OLED (PGOLED), are shown. Such devices fulfil the requirements to become an important part of ‘green photonics’.
Dalton Trans., 2014
The irreversible reaction of methyl triflate with neutral Re(i) tetrazolato complexes of the type... more The irreversible reaction of methyl triflate with neutral Re(i) tetrazolato complexes of the type fac-[Re(diim)(CO)3(L)], where diim is either 1,10-phenanthroline or 2,2'-bipyridine and L is a para substituted 5-aryltetrazolate, yielded the corresponding cationic methylated complexes. While methylation occurred regioselectively at the N4 position of the tetrazole ring, the cationic complexes were found to exist in solution as equilibrating mixtures of linkage isomers, where the Re(i) centre was bound to either the N1 or N2 atom of the tetrazole ring. The existence of these isomers was highlighted both by NMR and X-ray crystallography studies. On the other hand, the two isomers appeared indistinguishable by IR, UV-Vis and luminescence spectroscopy. The prepared cationic complexes are all brightly phosphorescent in fluid and rigid solutions, with emission originating from triplet metal-to-ligand charge transfer excited states. Compared to their neutral precursors, which emit from admixtures of triplet metal-to-ligand and ligand-to-ligand charge transfer states, the methylated complexes exhibit blue-shifted emission characterised by elongated excited state lifetimes and increased quantum yields. The nature of the excited states for both the neutral and the methylated complexes was probed by resonance Raman spectroscopy and with the aid of time-dependent density functional theory calculations. Lastly, both the neutral and the methylated species were used as emitting phosphors in the fabrication of Organic Light Emitting Diodes and Light Emitting Electrochemical Cells.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 29, 2015
The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxid... more The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae⋅HOEt)(L)4 ]2 (Ln=Eu(3+) , Er(3+) , Yb(3+) ; Ae=Na(+) , K(+) , Rb(+) ). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb(3+) and Er(3+) showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes (τobs ≈37-47 μs for Yb(3+) and τobs ≈4-6 μs for Er(3+) ) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu(3+) assemblies show bright red emission and a lumi...
MRS Proceedings, 1997
ABSTRACT In the present contribution a new hole transporting molecule belonging to the triphenyld... more ABSTRACT In the present contribution a new hole transporting molecule belonging to the triphenyldiamine family (N,N'-diphenyl-N,N'-bis(4-metylphenyl)- 1, 1'-biphenyl-4,4'- diamine) in a polycarbonate matrix is studied as the hole transport layer in a two layer device with Alq3 as emitting layer. The dependence of the electrical and emitting behaviour on the doping level is studied and compared with the vacuum deposited diamine layer also interfaced with Alq3
Advanced Materials For Optics and Electronics, 1999
ABSTRACT
Coordination Chemistry Reviews, 2011
Journal of Materials Chemistry C, 2013
ABSTRACT We investigated the nature of the emissive states in newly synthesized cyclometallated P... more ABSTRACT We investigated the nature of the emissive states in newly synthesized cyclometallated Pt complexes containing a chelating 2-pyridyl tetrazolate (2-PTZ) ligand, namely Pt(ppy)(2-PTZ), and Pt(F2ppy)(2-PTZ) as a solid-state phosphor, by examining their structural properties versus their phosphorescence (PH) and electroluminescence (EL) characteristics. It is found that the observed tuning of both PH and EL spectra, their red shift and shortening decay with increasing concentration in the complex blends are due to the competition between three emissive states: monomer, excimer and dimer. The pure dimer emission appeared in neat films, reaching a high PH quantum yield of about 75% and external EL efficiency approaching 10% for the OLED based on the neat Pt(F2ppy)(2-PTZ) complex film as an emitting layer (EML). X-ray diffraction proved the high structural order of the latter thin film. These findings have a direct impact on the design of a new OLED generation based on single phosphor multi-emission controlled by the structural order degree of the EML.