resumo
A series of steric phenylpyridazine based homoleptic iridium(iii) complexes (1-3) have been synthesized with novel one-pot methods. Single X-ray structural analyses are conducted on complexes 1 and 2 to reveal their coordination arrangement. These complexes exhibit a very strong green phosphorescence emission with high quantum yields of over 64%. The relationship between photophysical properties and the substituent nature of the complexes is discussed by density functional theory (DFT) and time-dependent DFT. Self-quenching is significantly reduced for these complexes in solid even at very high concentrations because the sterically hindered bicyclo [2.2.2] oct-2-ene and m-substituted CF3 spacers in the phosphor molecules lead to minimum bimolecular interactions. Accordingly, the electroluminescence device based on complex 3 exhibits a maximum luminous efficiency of 64.1 cd A(-1) with a high EQE of 25.2% at a high doping concentration of 15 wt%. Meanwhile, when neat 3 was adopted as the emitting layer, the non-doped green device gives a state-of-the-art EQE as high as 15.2% (40.1 cd A(-1)) along with CIE coordinates of (0.346, 0.599).
palavras-chave
LIGHT-EMITTING-DIODES; EFFECTIVE CORE POTENTIALS; EXTERNAL QUANTUM EFFICIENCY; AB-INITIO; MOLECULAR CALCULATIONS; ROLL-OFF; PHOSPHORESCENT OLEDS; ELECTROPHOSPHORESCENCE; DENSITY; THERMOCHEMISTRY
categoria
Chemistry
autores
Tong, BH; Wang, H; Chen, M; Zhou, SX; Hu, YY; Zhang, QF; He, GF; Fu, LS; Shi, HT; Jin, L; Zhou, HD
nossos autores
Lianshe Fu
Investigador Auxiliaragradecimentos
The authors acknowledge financial support from the National Natural Science Foundation of China (21572001 and 61675127), the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), and national funds through the FCT/MEC, FEDER under the PT2020 Partnership Agreement.