Strain-Mediated Second Harmonic Generation Enhancement of Bimetallic Metal–Organic Frameworks

Triggered by the demand of developing practical metal-organic framework (MOF) based nonlinear optical (NLO) devices, there is a surge of research interest in the regulation of NLO properties of MOFs. Strain engineering provides a new opportunity to regulate the optoelectronic properties of materials and device performance at the interface. Here we introduce the induction of the strain field in structures by constructing bimetallic Zn/Cu-MOFs. The NLO response of MOF1-9 with different metal element ratios was characterized in the near-infrared window. Surprisingly, MOF3 exhibited a giant second harmonic generation (SHG) enhancement compared with that of pristine Zn- and Cu-MOF. The determined second-order nonlinear susceptibility of MOF3 (∼19.86 p mV