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Near‐IR Emitting Iridium(III) Complexes with Heteroaromatic β‐Diketonate Ancillary Ligands for Efficient Solution‐Processed OLEDs: Structure–Property Correlations

2016; Wiley; Volume: 55; Issue: 8 Linguagem: Inglês

10.1002/anie.201509798

1521-3773

Sagar Kesarkar, Wojciech Mróz, Marta Penconi, Mariacecilia Pasini, Silvia Destri, Marco Cazzaniga, Davide Ceresoli, Patrizia R. Mussini, Clara Baldoli, Umberto Giovanella, Alberto Bossi,

Luminescence and Fluorescent Materials

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.