Efficient deep red and NIR OLEDs based on Ir(III) complexes fabricated by evaporation and solution processing

Abstract

Solution processing of organic light-emitting devices (OLEDs) becomes an attractive approach due to its low fabrication cost and accessibility to a broad range of materials. Near-infrared (NIR) OLEDs emerge as a practicable technological medium that can be widely used in phototherapy, optical imaging, remote communication, secured display and so on. We report here a couple of high-performance deep red OLEDs fabricated by evaporation processing and a series of NIR OLEDs fabricated by solution processing, in which the devices attain high maximum external quantum efficiencies (EQEs) of 12.68 %, 12.49 % and 3.80 % with the electroluminescence peaks at 673, 692 and 706 nm, respectively. The effects of functional substituents and p–π conjugation on the optoelectronic properties of these new Ir(III) phosphors have also been investigated. It can provide a new insight into developing highly efficient evaporation-processed and solution-processed OLEDs based on Ir(III) complexes with deep red and NIR emissions.