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RESEARCH PRODUCT

Enhancing the photoluminescence quantum yields of blue-emitting cationic iridium(iii) complexes bearing bisphosphine ligands

Eli Zysman-colmanPaul C. J. KamerAlexandra M. Z. SlawinDavid B. CordesLaura Martínez-sartiAdam Francis HenwoodAshu K. BansalDiego Rota MartirVincent Di MascioIfor D. W. SamuelHenk J. BolinkAntonio Pertegás

subject

PhotoluminescenceXantphosLigandNDASCationic polymerizationchemistry.chemical_element02 engineering and technologyBite angleQD Chemistry010402 general chemistry021001 nanoscience & nanotechnologyPhotochemistryElectrochemistry01 natural sciences0104 chemical sciencesInorganic Chemistrychemistry.chemical_compoundchemistryQDIridium0210 nano-technologyLuminescence

description

EZ-C acknowledges the University of St Andrews for financial support. We thank Johnson Matthey and Umicore AG for the gift of materials and Cihang Yu for the preparation of isopropxantphos. We thank Dr. Nail Shaveleev for the synthesis of NMS25. IDWS and AKB acknowledge support from EPSRC (EP/J01771X). This work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) MAT2014-55200. Herein we present a structure-property relationship study of thirteen cationic iridium (III) complexes of the form of [Ir(C^N)2(P^P)]PF6 in both solution and the solid state through systematic evaluation of six bisphosphine (P^P) ligands (xantphos, dpephos, dppe, Dppe, nixantphos and isopropxantphos). All of the complexes are sky-blue emissive, but their photoluminescence quantum yield (ΦPL) are generally low. However, strong and long-lived blue luminescence (λem: 471 nm; ΦPL = 52%; τe, of 13.5 μs) can be obtained by combining the reduced bite angle of the 1,2-bis-diphenylphosphinoethene (dppe) chelate with the bulky 2-(4,6-difluorophenyl)-4-mesitylpyridinato (dFmesppy) cyclometalating ligand. To the best of our knowledge this is the highest ΦPL and the longest τe reported for cyclometalated iridium(III) complexes bearing bisphosphine ligands. Light-emitting electrochemical cells (LEECs) were fabricated using lead complexes from this study, however due in part to the irreversible electrochemistry, no functional LEEC was achieved. Organic light-emitting diodes were successfully fabricated but only attained maximum external quantum efficiencies of 0.25%. Publisher PDF Peer reviewed

https://doi.org/10.1039/c5qi00177c