title: Near-IR Emitting Iridium(III) Complexes with Heteroaromatic β-Diketonate Ancillary Ligands for Efficient Solution-Processed OLEDs: Structure-Property Correlations.
abstract: Three NIR-emitting neutral Ir(III) complexes [Ir(iqbt)2 (dpm)] (1), [Ir(iqbt)2 (tta)] (2), and [Ir(iqbt)2 (dtdk)] (3) based on the 1-(benzo[b]thiophen-2-yl)-isoquinolinate (iqtb) were synthesized and characterized (dpm=2,2,6,6-tetramethyl-3,5-heptanedionate; tta=2-thienoyltrifluoroacetonate; dtdk=1,3-di(thiophen-2-yl)propane-1,3-dionate). The compounds emit between λ=680 and 850 nm with high luminescence quantum yields (up to 16 %). By combining electrochemistry, photophysical measurements, and computational modelling, the relationship between the structure, energy levels, and properties were investigated. NIR-emitting, solution-processed phosphorescent organic light-emitting devices (PHOLEDs) were fabricated using the complexes. The devices show remarkable external quantum efficiencies (above 3 % with 1) with negligible efficiency roll-off values, exceeding the highest reported values for solution-processible NIR emitters.
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Sagar
authors.initials: S
authors.lastname: Kesarkar
authors.affiliation: Istituto per lo Studio delle Macromolecole-, CNR, Via E. Bassini 15, 20133, Milano, Italy.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Mróz
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Penconi
authors.affiliation: Istituto per lo Studio delle Macromolecole-, CNR, Via E. Bassini 15, 20133, Milano, Italy.
authors.forename: Mariacecilia
authors.initials: M
authors.lastname: Pasini
authors.affiliation: Istituto per lo Studio delle Macromolecole-, CNR, Via E. Bassini 15, 20133, Milano, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Destri
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Cazzaniga
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Ceresoli
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milano, Italy.
authors.forename: Patrizia R
authors.identifier: http://orcid.org/0000-0003-4063-1563
authors.initials: PR
authors.lastname: Mussini
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Baldoli
authors.affiliation: Istituto per lo Studio delle Macromolecole-, CNR, Via E. Bassini 15, 20133, Milano, Italy. u.giovanella@ismac.cnr.it.
authors.forename: Umberto
authors.initials: U
authors.lastname: Giovanella
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari-, CNR and SmartMatLab Center, Via C. Golgi 19, 20133, Milano, Italy. alberto.bossi@istm.cnr.it.
authors.forename: Alberto
authors.identifier: http://orcid.org/0000-0001-9252-6218
authors.initials: A
authors.lastname: Bossi
keywords: density functional calculations; electrochemistry; iridium; organic light emitting diodes; phosphorescence