Benzotriazole-containing donor–acceptor–acceptor type cyclometalated iridium(III) complex for solution-processed near-infrared polymer light emitting diodes

• A novel iridium(III) complex of (CH3OTPA-BTz-Iq)2Irpic with a D-A-A structure was synthesized.
• The (CH3OTPA-BTz-Iq)2Irpic shows an emission at 718 nm and a shoulder at 790 nm in solution at 298 K.
• The (CH3OTPA-BTz-Iq)2Irpic-doped PLEDs exhibited a near-infrared EL emission peaked at 723 nm.
• The maximum EQE of 0.41% and a radiant intensity of 74.1 μW cm−2 were obtained in their doped PLEDs.

A novel near-infrared-emitting cyclometalated iridium(III) complex of (CH3OTPA-BTz-Iq)2Irpic containing benzotriazole unit with a donor–acceptor–acceptor (D-A-A) chromophore was synthesized and characterized. The optophysical, electrochemical and electroluminescent characteristics were primarily studied. A near-infrared emission peaked at 716 nm with a shoulder at 790 nm was exhibited in the (CH3OTPA-BTz-Iq)2Irpic dichloromethane solution at 298 K. In its optimized solution-processed polymer light-emitting diodes, a near-infrared electroluminescent emission peaked at 723 nm with a shoulder at 780 nm was observed with a maximum external quantum efficiency of 0.41% at 8.14 mA cm−2. This work indicates that introducing appropriate D and A units to develop D-A-A structure is an efficient approach to construct near-infrared-emitting iridium(III) complex in the polymer light-emitting diodes with suppressive efficiency roll-off.

A novel benzotriazole-containing donor-acceptor-acceptor type cyclometalated iridium(III) complex of (CH3OTPA-BTz-Iq)2Irpic was synthesized. Using it as a dopant and a blend of PVK and OXD-7 as a host matrix, the PLEDs exhibited a near-infrared (NIR) emission peaked at 723 nm and a shoulder at 780 nm with the maximum EQE of 0.41% at 8.14 mA cm−2. This work indicates that introducing appropriate D and A unit to develop D-A-A structure is an efficient approach to construct near-infrared-emitting iridium(III) complex and obtain high-efficiency near-infrared polymer light-emitting diodes with suppressive efficiency roll-off.Figure optionsDownload as PowerPoint slide