DOI: 10.1039/C6CC01414C
Page 3 of 3
ChemComm
manifested the complete exciton confinement on the emissive
molecular EMLs for super-resolution devices.
cores of these phosphors (inset of Fig. 3a). Ir(34NTCzPBI)3
endowed its devices with the significantly low driving voltages of
3.5 V for onset, <5.0 V and <6.0 V at 100 and 1000 cd m-2, which
F.H. and X.Z. contributed equally to this work. This project
was financially supported by NSFC (51373050), Education
Bureau of Heilongjiang Province (2014CJHB005) and the Fok
5
were several voltages lower than those of other devices (Fig. 3a 40 Ying-Tong Education Foundation for Young Teachers in the
and Table S2). Ir(34NTCzPBI)3 further realized the highest
efficiencies with the maxima of 27.7 cd A-1 for current efficiency
(CE), 15.4 lm W-1 for power efficiency (PE) and 8.3% for EQE,
accompanied with the negligible efficiency roll-offs as low as
Higher Education Institutions of China (141012).
Notes and references
a
Key Laboratory of Functional Inorganic Material Chemistry, School of
10 0.4% at 1000 cd m-2 for EQE (Fig. 3b and Table S2). In contrast,
the lowest device efficiencies of Ir(23NTCzPBI)3 were in accord
with its worst optical properties, due to its distorted configuration
for non-radiative transition and deficient encapsultion for exciton
quenching. The excellent comprehensive EL performance of
15 Ir(34NTCzPBI)3 makes it among the best solution-processable
phosphors for host-free devices. It is noteworthy that when using
TCTA as host, the EL performance of Ir(34NTCzPBI)3-doped
devices was instead decreased, contrary to the situations of other
two phosphors (Fig. S5). In this case, in comparison to its
20 analogues, the main reason for the best EL performance of
Ir(34NTCzPBI)3 should be attributed to its most uniformly
dispersed tbCzp groups, whose efficacy in energy and carrier
transfer and emissive center isolation can be comparable and even
superior to host matrix.
Chemistry and Materials, Heilongjiang University, Ministry of Education,
45 Harbin 150080, China. E-mail: hxu@hlju.edu.cn.
b
Key Laboratory for Organic Electronics and Information Displays
(KLOEID), Institute of Advanced Materials (IAM), Nanjing University of
Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
E-mail: iamxwzhang@njupt.edu.cn.
c
50
Key Laboratory of Flexible Electronics (KLOFE) & Institute of
Advanced Materials (IAM), Jiangsu National Synergetic Innovation
Center for Advanced Materials (SICAM), Nanjing Tech University
(NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
† Electronic Supplementary Information (ESI) available: Experimental
55 details, AFM images, thermal properties, optical properties and EL
performance data of the doped devices. See DOI: 10.1039/b000000x/
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Fig.3 a. EL spectra (inset) and luminance-current density (J)-voltage
curves of Ir(xyNTCzPBI)3-based bilayer spin-coated OLEDs; b.
Efficiency vs. luminance relationships of the devices.
In summary, a series of nanosize phosphors Ir(xyNTCzPBI)3
30 featured host-dopant integrated core-shell structure were
constructed on the basis of CTAC strategy. With the most
uniformly dispersed tbCzp groups, Ir(34NTCzPBI)3 realizes the
best optoelectronic properties, indicating the significance of the
peripheral-group distribution. The impressive EL performance of
35 its spin-coated nondoped devices makes it competent as single-
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