TY - JOUR
T1 - Low Amplified Spontaneous Emission Threshold and Efficient Electroluminescence from a Carbazole Derivatized Excited-State Intramolecular Proton Transfer Dye
AU - Mai, Van T.N.
AU - Shukla, Atul
AU - Mamada, Masashi
AU - Maedera, Satoshi
AU - Shaw, Paul E.
AU - Sobus, Jan
AU - Allison, Ilene
AU - Adachi, Chihaya
AU - Namdas, Ebinazar B.
AU - Lo, Shih Chun
N1 - Funding Information:
This work was funded by the Australian Research Council (DP160100700), JST ERATO Grant No. JPMJER1305, and JSPS KAKENHI Grant No. JP17K14531. E.B.N. is a recipient of UQ Fellowship. This work was performed in part at the Queensland node of the Australian National Fabrication Facility Queensland Node (ANFF-Q), a company established under the National Collaborative Research Infrastructure Strategy to provide nano- and microfabrication facilities for Australia's researchers.
Publisher Copyright:
Copyright © 2018 American Chemical Society.
PY - 2018/11/21
Y1 - 2018/11/21
N2 - The search for new classes of efficient electroluminescent organic laser dyes with low amplified spontaneous emission (ASE) threshold (Eth) and low optical losses is crucial toward the realization of organic injection lasers. In this work, we report in-depth studies of an organic semiconducting laser dye, benzo[d]thiazol-2-yl)-5-(9H-carbazol-9-yl)phenol (HBT-Cz), and compare the photophysical study with its parent HBT dye. While HBT is not laser-active in solution, the carbazole derivatized dye (i.e., HBT-Cz) showed a low solution ASE threshold of 21 mJ/cm2, which is comparable to a common high-performing commercial laser dye, Rhodamine 6G (Rh-6G). HBT-Cz also exhibited a low film ASE threshold of 2.4 μJ/cm2 with a low optical loss coefficient of 1.5 cm-1, which is the lowest waveguide loss coefficient reported for solution-processed organic semiconductors. Organic light-emitting diodes based on this material showed a high maximum EQE of 1.9%, which is close to the theoretical EQE limit of the emitter, and high brightness of >2,300 cd/m2. Further insights into the lasing properties of the material were provided by steady state UV-visible spectroscopy, and transient absorption spectroscopy, shedding light on excited-state species absorption. To the best of our knowledge, this is the first report of a solution-processable organic small molecular dye, exhibiting a low ASE threshold and lowest optical loss coefficient, coupled with efficient electroluminescence.
AB - The search for new classes of efficient electroluminescent organic laser dyes with low amplified spontaneous emission (ASE) threshold (Eth) and low optical losses is crucial toward the realization of organic injection lasers. In this work, we report in-depth studies of an organic semiconducting laser dye, benzo[d]thiazol-2-yl)-5-(9H-carbazol-9-yl)phenol (HBT-Cz), and compare the photophysical study with its parent HBT dye. While HBT is not laser-active in solution, the carbazole derivatized dye (i.e., HBT-Cz) showed a low solution ASE threshold of 21 mJ/cm2, which is comparable to a common high-performing commercial laser dye, Rhodamine 6G (Rh-6G). HBT-Cz also exhibited a low film ASE threshold of 2.4 μJ/cm2 with a low optical loss coefficient of 1.5 cm-1, which is the lowest waveguide loss coefficient reported for solution-processed organic semiconductors. Organic light-emitting diodes based on this material showed a high maximum EQE of 1.9%, which is close to the theoretical EQE limit of the emitter, and high brightness of >2,300 cd/m2. Further insights into the lasing properties of the material were provided by steady state UV-visible spectroscopy, and transient absorption spectroscopy, shedding light on excited-state species absorption. To the best of our knowledge, this is the first report of a solution-processable organic small molecular dye, exhibiting a low ASE threshold and lowest optical loss coefficient, coupled with efficient electroluminescence.
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U2 - 10.1021/acsphotonics.8b00907
DO - 10.1021/acsphotonics.8b00907
M3 - Article
AN - SCOPUS:85055527356
SN - 2330-4022
VL - 5
SP - 4447
EP - 4455
JO - ACS Photonics
JF - ACS Photonics
IS - 11
ER -