Modulation of Third-Order Nonlinear Optical Properties by Interfacial Interactions of Defected Bimetallic-MOF@CeO<sub>2</sub>
Xiao Yan Xu, Yujie Zhao, Kangshuai Geng, Yupei Sun, Yi Wei, Hongwei Hou
Abstract
MOF@CeO 2 composites with good interfacial compatibility have garnered significant attention in the field of third-order nonlinear optics (NLO). However, the interfacial interaction between the MOFs and CeO 2 is commonly weak, which severely weakens the third-order NLO properties of the composites. In this study, we chose the parent Zn-MOF ({[Zn(BPAN) 0.5 (ndcpa)]·DMA·H 2 O} n ) (BPAN = 9,10–bis(4–pyridyl)anthracene and H 2 ndcpa = naphthalene-2,6-dicarboxylicacid) and synthesized bimetallic-MOFs (ZnNi-MOF and ZnCo-MOF) by solvent-assisted metal-ion exchange. The defect sites originating from the exchange make the interface interaction of bimetallic-MOF@CeO 2 composites (ZnNi-MOF@CeO 2 and ZnCo-MOF@CeO 2 ) stronger. The third-order NLO results indicate bimetallic-MOF@CeO 2 composites display enhanced reverse saturable absorption and self-defocusing refraction properties compared to Zn-MOF@CeO 2, which can be attributed to efficient charge transfer at interfaces. Transient absorption spectra and theoretical calculation revealed that good interfacial compatibility significantly reduced interfacial energy loss, enhanced electron transfer efficiency, and positively modulated the third-order NLO properties. This study provides new insights and methodologies for the design and development of novel third-order NLO composites.