0000000000243283

AUTHOR

Giulia Longo

0000-0002-1163-1110

Self-absorption in a light-emitting electrochemical cell based on an ionic transition metal complex

We report on the quantitative and qualitative effects of self-absorption in light-emitting electrochemical cells (LECs) based on ionic transition metal complexes (iTMCs), as measured in-situ during electric driving. A yellow-emitting iTMC-LEC comprising an active material thickness of 95 nm suffers a 4% loss of the emission intensity to self-absorption, whereas the same type of device but with a larger active-material thickness of 1 mu m will lose a significant 40% of the light intensity. We also find that the LEC-specific effect of doping-induced self-absorption can result in a drift of the emission spectrum with time for iTMC-LECs, but note that the overall magnitude of doping-induced sel…

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Photoluminescence quantum yield exceeding 80% in low dimensional perovskite thin-films via passivation control

Quasi-2D perovskites with the BA : MA molar ratio equal to 3 : 3 show a remarkable PLQY exceeding 80%, thanks to the use of an electron donor as the passivating agent. These films have been applied in LEDs that exhibit high brightness exceeding 1000 cd m−2 and current efficiencies >3 cd A−1.

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Shine bright or live long: substituent effects in [Cu(N^N)(P^P)]+-based light-emitting electrochemical cells where N^N is a 6-substituted 2,2'-bipyridine

We report [Cu(P^P)(N^N)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 6-methyl-2,2′-bipyridine (Mebpy), 6-ethyl-2,2′-bipyridine (Etbpy), 6,6′-dimethyl-2,2′-bipyridine (Me2bpy) or 6-phenyl-2,2′-bipyridine (Phbpy). The crystal structures of [Cu(POP)(Phbpy)][PF6]·Et2O, [Cu(POP)(Etbpy)][PF6]·Et2O, [Cu(xantphos)(Me2bpy)][PF6], [Cu(xantphos)(Mebpy)][PF6]·CH2Cl2·0.4Et2O, [Cu(xantphos)(Etbpy)][PF6]·CH2Cl2·1.5H2O and [Cu(xantphos)(Phbpy)][PF6] are described; each copper(I) centre is distorted tetrahedral. In the crystallographically determined structures, the N^N domain in [Cu(xantphos)(Phbpy)]+ and [Cu(…

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High efficiency single-junction semitransparent perovskite solar cells

Semitransparent perovskite solar cells with a high power conversion efficiency (PCE) above 6% and 30% full device transparency have been achieved by implementing a thin perovskite layer and a simple foil compatible layout.

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Perovskite solar cells prepared by flash evaporation

A simple vacuum deposition method for the preparation of high quality hybrid organic-inorganic methylammonium lead iodide perovskite thin films is reported. When sandwiched in between organic charge transporting layers, such films lead to solar cells with a power conversion efficiency of 12.2%.

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Fully Vacuum-Processed Wide Band Gap Mixed-Halide Perovskite Solar Cells

Methylammonium lead mixed-halide perovskites MAPb(BrxI1–x)3 are promising materials for the preparation of tandem devices. When exposed to light, MAPb(BrxI1–x)3 segregates in iodide- and bromide-rich phases, limiting the achievable photovoltage and hence the attainable device efficiency. To date only solution-processed mixed-halide perovskites have been demonstrated. We present fully vacuum-deposited mixed-halide perovskite thin films with band gap of 1.72 and 1.87 eV, prepared by controlling the deposition rates of the different halide precursors. When used in thin-film devices, these materials lead to power conversion efficiencies of 15.9 and 10.5%, respectively, which are among the highe…

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Efficient photovoltaic and electroluminescent perovskite devices.

Planar diode structures employing hybrid organic–inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method.

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Effect of the precursor's stoichiometry on the optoelectronic properties of methylammonium lead bromide perovskites

International audience; Methylammonium lead bromide (MAPbBr 3) perovskites have been widely studied in applications such as lasers and light-emitting diodes, thanks to their favorable bandgap, efficient charge transport, and the possibility of processing by simple solution methods. The film morphology has a large impact on the optical and electronic properties of the material; hence the deposition methods and the type of precursors used are crucial in the preparation of efficient optoelectronic devices. Here we studied the effect of the precursor´s stoichiometry of solution processed MAPbBr 3 thin films on their optical and electronic properties. We found a drastic effect of the stoichiomet…

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Luminescent copper(i) complexes with bisphosphane and halogen-substituted 2,2′-bipyridine ligands

Heteroleptic [Cu(P^P)(N^N)][PF6] complexes, where N^N is a halo-substituted 2,2'-bipyridine (bpy) and P^P is either bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9- dimethylxanthene (xantphos) have been synthesized and investigated. To stabilize the tetrahedral geometry of the copper(I) complexes, the steric demands of the bpy ligands have been increased by introducing 6- or 6,6'-halo-substituents in 6,6'-dichloro-2,2'-bipyridine (6,6'-Cl2bpy), 6-bromo-2,2'- bipyridine (6-Brbpy) and 6,6'-dibromo-2,2'-bipyridine (6,6'-Br2bpy). The solid-state structures of [Cu(POP)(6,6'-Cl2bpy)][PF6], [Cu(xantphos)(6,6'-Cl2bpy)][PF6].CH2Cl2, [Cu(POP)(6-Brbpy)][PF6] and [Cu(xantp…

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Hybrid perovskites for light-emitting and photovoltaic devices

El objetivo de esta tesis es el desarrollo de métodos y materiales apropiados para la preparación de capas delgadas de perovskitas híbridas, y su implementación en dispositivos optoelectrónicos. Se dedicará particular atención a las relaciones entre la naturaleza del material, el método de deposición y las propiedades optoelectrónicas. El trabajo está organizado como sigue: - Células solares de perovskitas preparadas por evaporación flash. Se desarrolla un simple método de evaporación por la preparación de células solares. - Dispositivos de perovskita con alta eficiencia fotovoltaica y electroluminiscente. En este capítulo se presentan dispositivos optoelectrónicos de perovskitas preparados…

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Exceptionally long-lived light-emitting electrochemical cells: multiple intra-cation π-stacking interactions in [Ir(C^N)2(N^N)][PF6] emitters

A series of cyclometalated iridium(iii) complexes [Ir(C^N)2(N^N)][PF6] (N^N = 2,2′-bipyridine (1), 6-phenyl-2,2′-bipyridine (2), 4,4′-di-tert-butyl-2,2′-bipyridine (3), 4,4′-di-tert-butyl-6-phenyl-2,2′-bipyridine (4); HC^N = 2-(3-phenyl)phenylpyridine (HPhppy) or 2-(3,5-diphenyl)phenylpyridine (HPh2ppy)) are reported. They have been synthesized using solvento precursors so as to avoid the use of chlorido-dimer intermediates, chloride ion contaminant being detrimental to the performance of [Ir(C^N)2(N^N)][PF6] emitters in light-electrochemical cell (LEC) devices. Single crystal structure determinations and variable temperature solution 1H NMR spectroscopic data confirm that the pendant pheny…

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High Photoluminescence Quantum Yields in Organic Semiconductor-Perovskite Composite Thin Films.

One of the obstacles towards efficient radiative recombination in hybrid perovskites is a low exciton binding energy, typically in the orders of tens of meV. It has been shown that the use of electron-donor additives can lead to a substantial reduction of the non-radiative recombination in perovskite films. Herein, the approach using small molecules with semiconducting properties, which are candidates to be implemented in future optoelectronic devices, is presented. In particular, highly luminescent perovskite-organic semiconductor composite thin films have been developed, which can be processed from solution in a simple coating step. By tuning the relative concentration of methylammonium l…

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[Cu(bpy)(P^P)]+ containing light-emitting electrochemical cells: improving performance through simple substitution

Light-emitting electrochemical cells (LECs) containing [Cu(POP)(N^N)][PF6] (POP = bis(2-diphenylphosphinophenyl)ether, N^N = 6-methyl- or 6,6′-dimethyl-2,2′-bipyridine) exhibit luminance and efficiency surpassing previous copper(i)-containing LECs.

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Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr 3 Perovskite with Reduced Crystal Size

Methylammonium lead bromide perovskite (MAPbBr3) has been widely investigated for applications in visible perovskite light-emitting diodes (LEDs). Fine-tuning of the morphology and of the crystal size, from the microscale down to the quantum confinement regime, has been used to increase the photoluminescence quantum yield (PLQY). However, the physical processes underlying the PL emission of this perovskite remain unclear. Here, we elucidate the origin of the PL emission of polycrystalline MAPbBr3 thin films by different spectroscopic techniques. We estimate the exciton binding energy, the reduced exciton effective mass, and the trap density. Moreover, we confirm the coexistence of free carr…

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Highly luminescent perovskite–aluminum oxide composites

In this communication we report on the preparation of CH3NH3PbBr3 perovskite/Al2O3 nanoparticle composites in a thin film configuration and demonstrate their high photoluminescence quantum yield. The composite material is solution-processed at low temperature, using stable alumina nanoparticle dispersions. There is a large influence of the alumina nanoparticle concentration on the perovskite morphology and on its photoluminescence.

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CCDC 1422375: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1584756: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1584755: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1422372: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1019228: Experimental Crystal Structure Determination

Related Article: Andreas M. Bünzli, Edwin C. Constable, Catherine E. Housecroft, Alessandro Prescimone, Jennifer A. Zampese, Giulia Longo, Lidón Gil-Escrig, Antonio Pertegás, Enrique Ortí, Henk J. Bolink|2015|Chemical Science|6|2843|doi:10.1039/C4SC03942D

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CCDC 1535142: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1583875: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1584757: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1429456: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1535141: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1019229: Experimental Crystal Structure Determination

Related Article: Andreas M. Bünzli, Edwin C. Constable, Catherine E. Housecroft, Alessandro Prescimone, Jennifer A. Zampese, Giulia Longo, Lidón Gil-Escrig, Antonio Pertegás, Enrique Ortí, Henk J. Bolink|2015|Chemical Science|6|2843|doi:10.1039/C4SC03942D

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CCDC 1584754: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1422374: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1019226: Experimental Crystal Structure Determination

Related Article: Andreas M. Bünzli, Edwin C. Constable, Catherine E. Housecroft, Alessandro Prescimone, Jennifer A. Zampese, Giulia Longo, Lidón Gil-Escrig, Antonio Pertegás, Enrique Ortí, Henk J. Bolink|2015|Chemical Science|6|2843|doi:10.1039/C4SC03942D

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CCDC 1009455: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Edwin C. Constable, Catherine E. Housecroft, Markus Neuburger, Alessandro Prescimone, Giulia Longo, Antonio Pertegás, Michele Sessolo, Henk J. Bolink|2014|Dalton Trans.|43|16593|doi:10.1039/C4DT02847C

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CCDC 996509: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Edwin C. Constable, Catherine E. Housecroft, Markus Neuburger, Alessandro Prescimone, Giulia Longo, Antonio Pertegás, Michele Sessolo, Henk J. Bolink|2014|Dalton Trans.|43|16593|doi:10.1039/C4DT02847C

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CCDC 1535144: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1422373: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1584752: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1584753: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1435492: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Antonio Pertegás, Giulia Longo, Laura Martínez, Jesús Cerdá, José M. Junquera-Hernández, Alessandro Prescimone, Edwin C. Constable, Catherine E. Housecroft, Enrique Ortí, Henk J. Bolink|2016|J.Mater.Chem.C|4|3857|doi:10.1039/C5TC03725E

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CCDC 1535143: Experimental Crystal Structure Determination

Related Article: Sarah Keller, Alessandro Prescimone, Henk Bolink, Michele Sessolo, Giulia Longo, Laura Martínez-Sarti, José M. Junquera-Hernández, Edwin C. Constable, Enrique Ortí, Catherine E. Housecroft|2018|Dalton Trans.|47|14263|doi:10.1039/C8DT01338A

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CCDC 1019227: Experimental Crystal Structure Determination

Related Article: Andreas M. Bünzli, Edwin C. Constable, Catherine E. Housecroft, Alessandro Prescimone, Jennifer A. Zampese, Giulia Longo, Lidón Gil-Escrig, Antonio Pertegás, Enrique Ortí, Henk J. Bolink|2015|Chemical Science|6|2843|doi:10.1039/C4SC03942D

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