The 63rd JSAP Spring Meeting, 2016

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12 Organic Molecules and Bioelectronics » 12.4 Organic light-emitting devices and organic transistors

[21a-W521-1~10] 12.4 Organic light-emitting devices and organic transistors

Mon. Mar 21, 2016 9:30 AM - 12:15 PM W521 (W5)

Hajime Nakanotani(Kyushu Univ.), Yutaka Noguchi(Meiji Univ.)

10:00 AM - 10:15 AM

▲ [21a-W521-3] Quasi-continuous-wave lasing in a solvent-free liquid molecular semiconductor

〇JeanCharles Ribierre1,2, Atula S.D. Sandanayaka1,2, Ju-Hyung Kim3, Delphine Pitrat4, Li Zhao1, Toshinori Matsushima1,2, Chantal Andraud4, Chihaya Adachi1,2 (1.OPERA, Kyushu Univ., 2.JST ERATO, 3.Pukyong Univ., 4.ENS Lyon)

Keywords:liquid molecular semiconductor,organic DFB laser,continuous wave lasing

We report on the fabrication of quasi-continuous-wave (quasi-cw) organic semiconductor distributed feedback (DFB) lasers based on a gain medium containing a solvent-free liquid 9-(2-ethylhexyl) carbazole (EHCz) host doped with a highly fluorescent heptafluorene derivative.1,2 In order to suppress the triplet losses in the quasi-cw regime, we introduce oxygen as triplet scavenger in the gain medium by simply bubbling the liquid semiconductor with oxygen for 10 minutes. The presence of oxygen in the solvent-free liquid does not lead to any quenching of the singlet excitons. However, singlet-triplet exciton annihilation leading to a significant quenching of the emission at high excitation intensities is nearly suppressed.The influence of the oxygenation on the properties of the quasi-cw DFB lasers is then investigated in details by optically-pumping these devices with 10 ps pulses at various repetition rates. The oxygenated DFB lasers show a threshold of about 2 microJ/cm2, which is lower than that obtained in nitrogenated liquid devices and which is independent of the repetition rate in the range between 10 kHz and 4 MHz. Overall, this study demonstrates that the use of oxygen as triplet quencher is very promising for the development of optically-pumped cw organic semiconductor lasers.

[1] E. Y. Choi et al., Opt. Express 21, 11368 (2013).
[2] J.H. Kim, M. Inoue, L. Zhao, T. Komino, S. Seo, J.C. Ribierre and C. Adachi, Appl. Phys. Lett. 106, 053302 (2015).
[3] L. Zhao, M. Inoue, K. Yoshida, A.S.D. Sandanayaka, J.H. Kim, J.C. Ribierre and C. Adachi, IEEE J. Sel. Top. Quant. Electron. 22, 1300209 (2016).