Structural interpenetration in metal–organic frameworks (MOFs) significantly impacts on their properties and functionalities. However, understanding the interpenetration on third-order nonlinear optics (NLO) of MOFs have not been reported to date. Herein, we report two 3D porphyrinic MOFs, a 2-fold interpenetrated [Zn2(TPyP)­(AC)2] (ZnTPyP-1) and a noninterpenetrated [Zn3(TPyP)­(H2O)2(C2O4)2] (ZnTPyP-2), constructed from 5,10,15,20-tetra­(4-pyridyl)­porphyrin (TPyP­(H2)) and Zn­(NO3)2 (AC = acetate, C2O4 = oxalate). ZnTPyP-1 achieves excellent optical limiting (OL) performance with a giant nonlinear absorption coefficient (3.61 × 106 cm/GW) and large third-order susceptibility (7.73 × 10–7 esu), which is much better than ZnTPyP-2 and other reported OL materials. The corresponding MOFs nanosheets are dispersed into a polydimethylsiloxane (PDMS) matrix to form highly transparent and flexible MOFs/PDMS glasses for practical OL application. In addition, the OL response optimized by adjusting the MOFs concentration in the PDMS matrix and the type of metalloporphyrin are discussed in the ZnTPyP-1 system. The theoretical calculation confirmed that the abundant π–π interaction from porphyrinic groups in the interpenetrated framework increased the electron delocalization/transfer and boosted the OL performance. This study opens a new avenue to enhance OL performance by the construction of interpenetrated structures and provides a new approach for the preparation of transparent and flexible MOF composites in nonlinear optical applications.

Regulating nonlinear optical (NLO) property of metal−organic frameworks (MOFs) is of pronounced significance for their scientific research and practical application, but the regulation through external stimuli is still a challenging task. Here we prepare and electrically control the nonlinear optical regulation of conductive MOFs Cu-HHTP films with [001]- (Cu-HHTP[001]) and [100]-orientations (Cu-HHTP[100]). Z-scan results show that the nonlinear absorption coefficient (β) of Cu-HHTP[001] film (7.60 × 10−6 m/W) is much higher than that of Cu-HHTP[100] film (0.84 × 10−6 m/W) at 0 V and the β of Cu-HHTP[001] and Cu-HHTP[100] films gradually increase to 3.84 × 10−5 and 1.71 × 10−6 m/W at 10 V by increasing the applied voltage, respectively. Due to 2D Cu-HHTP having anisotropy of charge transfer in different orientations, the NLO of MOFs film can be dependent on their growth orientations and improved by tuning the electrical field. This study provides more avenues for the regulation and NLO applications of MOFs.

Benefiting from the strong inherent π-conjugation properties, the integration of Ti4L6 (L = embonate) cages and various N, N-chelated transition-metal cations into tightly packed structures accurately lead to the high-performance...