School of Physical Science and Technology, Soochow University, Suzhou 215006, China.
Department of Physics, Harbin Institute of Technology, Harbin 150001, China.
Molecules. 2022 Dec 19;27(24):9059. doi: 10.3390/molecules27249059.
Optical nonlinearities of two all-carbon twistacenes, and , with the different π-conjugated central bridges were investigated. The nonlinear absorption properties of these compounds were measured using the femtosecond Z-scan with wavelengths between 650 and 900 nm. It has been found that the nonlinear absorption originated from two-photon absorption (TPA) and TPA-induced excited state absorption (ESA), wherein demonstrates higher performance than . The TPA cross section of (4300 GM) is nearly 4.3 times larger than that of at 650 nm. Moreover, the different central structures modulate the intensity of ESA at 532 nm, and exhibits an excellent ESA at 532 nm with multi-pulse excitation. Meanwhile, the result of data fitting and quantum chemistry calculation shows that the enhancement of nonlinear absorption in is due to the extended π- conjugated bridge and improved delocalization of π-electrons. These all-carbon twistacenes could yield potential applications in optical power limiting (OPL) technology.
研究了具有不同π-共轭中心桥的两种全碳扭苯， 和 ，它们的光学非线性。使用波长在 650 到 900nm 之间的飞秒 Z 扫描法测量了这些化合物的非线性吸收特性。研究发现，非线性吸收源于双光子吸收（TPA）和 TPA 诱导的激发态吸收（ESA），其中 表现出比 更高的性能。在 650nm 处， 的 TPA 截面（4300GM）大约是 的 4.3 倍。此外，不同的中心结构调节了 532nm 处 ESA 的强度，并且 在多脉冲激发下表现出优异的 532nm ESA。同时，数据拟合和量子化学计算的结果表明， 在非线性吸收增强是由于扩展的 π-共轭桥和改善的π-电子离域。这些全碳扭苯在光学限幅（OPL）技术中可能具有潜在的应用。
