Zhang Mingang, Xu Xiangdong, Liu Jinrong, Jiang Yadong, Wang Jun, Dong Ningning, Chen Chenduan, Zhu Baohua, Liang Yuning, Fan Ting, Xu Jimmy
School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
ACS Appl Mater Interfaces. 2022 Jul 19. doi: 10.1021/acsami.2c06476.
Given the substantial π-electron delocalization observed in 4--dimethylamino-4--methyl-stilbazolium tosylate (DAST), a high third-order nonlinear optical response can be expected that might manifest itself in various ways for potential applications. To probe the possibility and assess its potential, all-organic DAST-polymethyl methacrylate (PMMA) composite films were prepared by a simple solution casting method, and their nonlinear absorption performances were measured by an open-aperture Z-scan system. The results reveal that under irradiation by a 380 fs laser pulse at 520 nm or a 6 ns laser pulse at 532 nm, the DAST-PMMA composite films with a DAST concentration of 0.125 wt % exhibit similar giant optical limiting (OL) responses with OL threshold of 7.84 or 0.37 GW cm, both superior to those of most organic and inorganic OL materials measured under similar conditions. These all-organic composite films show high flexibility, and interestingly, their OL responses can remain stable even after exposure to air for 3 months. The superior OL behaviors of such materials in the femtosecond and nanosecond regimes are attributed to the two-photon absorption and the combination of two-photon absorption and excited-state absorption, respectively. The simple preparation, high flexibility, giant OL responses, and excellent environmental stability suggest that such novel all-organic composite films hold great potential for applications in flexible OL devices.
鉴于在对甲苯磺酸4-二甲基氨基-4'-甲基-二苯乙烯基碘鎓盐（DAST）中观察到大量的π电子离域，预计其具有较高的三阶非线性光学响应，这可能会以各种方式表现出来，具有潜在的应用价值。为了探究这种可能性并评估其潜力，采用简单的溶液浇铸法制备了全有机DAST-聚甲基丙烯酸甲酯（PMMA）复合薄膜，并通过开孔Z扫描系统测量了它们的非线性吸收性能。结果表明，在520 nm波长的380 fs激光脉冲或532 nm波长的6 ns激光脉冲照射下，DAST浓度为0.125 wt%的DAST-PMMA复合薄膜表现出相似的巨大光学限幅（OL）响应，其OL阈值分别为7.84或0.37 GW/cm²，均优于在类似条件下测量的大多数有机和无机OL材料。这些全有机复合薄膜具有很高的柔韧性，有趣的是，即使在空气中暴露3个月后，它们的OL响应仍能保持稳定。这种材料在飞秒和纳秒 regime下优异的OL行为分别归因于双光子吸收以及双光子吸收和激发态吸收的组合。简单的制备方法、高柔韧性、巨大的OL响应以及出色的环境稳定性表明，这种新型全有机复合薄膜在柔性OL器件中具有巨大的应用潜力。
