Ma Zhi-Zhou, Wang Zirui, Li Qiao-Hong, Wang Yan-Yue, Gu Zhi-Gang, Zhang Jian
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian 350108, China.
Nano Lett. 2024 Apr 10;24(14):4186-4193. doi: 10.1021/acs.nanolett.4c00194. Epub 2024 Mar 28.
Achieving metal-organic frameworks (MOFs) with nonlinear optical (NLO) switching is profoundly important. Herein, the conductive MOFs Cu-TCNQ phase I (Ph-I) and phase II (Ph-II) films were prepared using the liquid-phase-epitaxial layer-by-layer spin-coating method and steam heating method, respectively. Electronic experiments showed that the Ph-II film could be changed into the Ph-I film under an applied electric field. The third-order NLO results revealed that the Ph-I film had a third-order nonlinear reverse saturation absorption (RSA) response and the Ph-II film displayed a third-order nonlinear saturation absorption (SA) response. With increases in the heating time and applied voltage, the third-order NLO response realized the reversible transition between SA and RSA. The theoretical calculations indicated that Ph-I possessed more interlayer charge transfer, resulting in a third-order nonlinear RSA response that was stronger than that of Ph-II. This work applies phase-transformed MOFs to third-order NLO switching and provides new insights into the nonlinear photoelectric applications of MOFs.
实现具有非线性光学（NLO）开关功能的金属有机框架（MOF）具有极其重要的意义。在此，分别采用液相外延逐层旋涂法和蒸汽加热法制备了导电MOF Cu-TCNQ的I相（Ph-I）和II相（Ph-II）薄膜。电子实验表明，在施加电场的情况下，Ph-II薄膜可转变为Ph-I薄膜。三阶NLO结果显示，Ph-I薄膜具有三阶非线性反向饱和吸收（RSA）响应，而Ph-II薄膜表现出三阶非线性饱和吸收（SA）响应。随着加热时间和施加电压的增加，三阶NLO响应实现了SA和RSA之间的可逆转变。理论计算表明，Ph-I具有更多的层间电荷转移，导致其三阶非线性RSA响应比Ph-II更强。这项工作将相转变MOF应用于三阶NLO开关，并为MOF的非线性光电应用提供了新的见解。
