Low Amplified Spontaneous Emission Threshold from Organic Dyes Based on Bis-stilbene
Low Amplified Spontaneous Emission Threshold from Organic Dyes Based on Bis-stilbene
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DOI：
10.1002/adfm.201802130
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发表时间：
2018-08-08
影响因子：
19
通讯作者：
Adachi, Chihaya
中科院分区：
文献类型：
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作者：
Mamada, Masashi;Fukunaga, Toshiya;Adachi, Chihaya
以双二苯乙烯-咔唑（BSBCz）为基料，制备了具有高溶解度和双极性特性的新型有机激光染料。该材料在溶液、晶体、混合薄膜和整齐薄膜中具有较高的光致发光量子产率和较大的辐射速率常数。烷基的引入显著提高了BSBCz的溶解度，烷基取代衍生物溶液处理膜的自发发射阈值被放大，低至0.59 μ J cm(-2)，与真空沉积的BSBCz膜相当。另一方面，BSBCz （BSBCz- cn）上的氰基取代增加了电子接受性能，导致发射波长的深色位移和双极行为的改善。在bsbcz - cn掺杂的薄膜中，实现了0.63 μ J cm（-2）的ASE阈值，这是具有绿色发射的有机激光染料的最低阈值之一。此外，基于BSBCz-CN整齐薄膜的有机发光二极管显示出1.8%的外量子效率，并且可以承受脉冲操作下高达500 A cm（-2）的高电流密度注入。这些特性以及低激发态吸收截面使这些材料成为现有有机激光染料库的杰出补充，特别是在电泵浦激光器中。
Advanced organic laser dyes exhibiting high solubility and bipolar behavior are developed based on a structure combining bis-stilbene with carbazole (BSBCz). The materials show high photoluminescence quantum yields and large radiative rate constants in solutions, crystals, and blend and neat films. The introduction of alkyl groups significantly improves the solubility of BSBCz, and solution-processed films of the alkyl-substituted derivatives exhibit amplified spontaneous emission thresholds as low as 0.59 mu J cm(-2), which is comparable to those of vacuum-deposited BSBCz films. On the other hand, cyano-substitution on BSBCz (BSBCz-CN) increases electron-accepting properties, resulting in a bathochromic shift of the emission wavelength and improved bipolar behavior. In a BSBCz-CN-doped film, a low ASE threshold of 0.63 mu J cm(-2) is achieved, which is one of the lowest values for organic laser dyes with green emission. In addition, organic light-emitting diodes based on BSBCz-CN neat films exhibit external quantum efficiencies of 1.8% and could withstand injection of high current densities of up to 500 A cm(-2) under pulse operation. These properties along with low excited-state absorption cross sections make these materials an outstanding addition to the existing library of organic laser dyes, especially for consideration in electrically pumped lasers.