Experimental and Theoretical Studies on Effects of Structural Modification of Tin Nanoclusters for Third-Order Nonlinear Optical Properties

Abstract

Tin oxide based materials have attracted much attention as new sources for nonlinear optical (NLO) devices, while the electronic mechanism behind the structure and nonlinearity is still unclear. In this work, by precisely controlling different functionalization ligands, here a series of binuclear [( n BuSn) 2 (TEOA) 2 L 2 ] (L = monocarboxylic acid ligand) complexes have been synthesized and characterized; we also adopted a new method to make the metal clusters and PMMA blend together for NLO testing. Importantly, the electronic structure, static thirdorder NLO properties, sum over states (SOS) have been studied by both experimental and density function theory (DFT) analysis. The effects for general NLO polarizability under various conditions, including different substitutions ligands and replacement of the metal cores, have been further investigated. The results indicate the static second hyperpolarizabilities (γ) is inversely proportional to the band gap decreases. Notably, the theory predicts that the third-order nonlinear coefficient will double through the synergistic effects of pull−push groups. The hole−electron analysis of the main excited states indicates the simultaneous introduction of pull−push electron groups into the system cause the excitation of the valence layer from LE to LLCT, which also leads to significant increase in the γ value of complex 13. This work demonstrates that an efficient adjustment for the intensity of NLO polarizability can be achieved by regulating the substitutions and the material structures, providing a new potential for the application of tin-oxo clusters in the field of nonlinear optics.

Novel Third-Order Nonlinear Optical Materials with Craig-Möbius Aromaticity

“…This conclusion is also consistent with our previous results. 22,30 The UV−vis spectra of three kinds of structures in Figure 4 and Figure S4 show that Os-2 and Os-3 have a significant redshift and a larger response intensity compared to Os-1 in the low-energy part. This is consistent with the conclusion obtained by molecular orbital analysis.…”

“…20−28 Our group has studied the third-order NLO properties of a series of metal clusters, metal-oxo clusters, and metal−organic frameworks in experiments and theoretical calculations. 20,22,29−31 The results show that the electron delocalization can be enhanced by adjusting the metal cluster core structure, 30 by ligand type, 22 and by constructing interspersed framework structures, 29 resulting in a richer π−π interaction and effectively improving the thirdorder NLO response. Meanwhile, aromatic molecules have high delocalization and stability, but the interesting subject of Craig-Mobius aromatic complexes as excellent third-order NLO materials has been rarely addressed.…”

Silver‐Templated γ‐Keggin Alkyltin‐Oxo Cluster: Electronic Structure and Optical Limiting Effect

“…The minimum normalized transmittance (Tmin) at the focal point is about 0.29 for AgSn 12 sample, which is better than the reported Sn 2 O 2 clusters. [42] Moreover, the output fluence of AgSn 12 sample linearly increases at low-incident fluence, and deviates from the linearity at high-incident fluence (Figure 4c). These results indicate that the AgSn 12 cluster exhibits the typical optical limiting effect.…”

“…The value of γ for AgSn 12 is 1.31 × 10 5 a.u., which is larger than that of reported Sn 2 O 2 clusters. [42] The third-order NLO properties of known Sn 2 O 2 clusters are mainly derived from the conjugated organic ligands, and have little relation to the SnÀ O moiety. However, different from these Sn 2 O 2 clusters, there is not any conjugated organic ligand existing in AgSn 12 .…”

Non-alkyl tin-oxo clusters as new-type patterning materials for nanolithography

“…In order to solve this problem, atomically precise tin-oxo clusters (TOCs) have emerged, and a few organotin clusters have been con-structed through the hydrolysis and condensation of alkyltin precursors [6][7][8][9][10]. As the cluster states of tin oxide, TOCs not only enrich the members of Sn-O materials, but also provide good opportunity for in-depth understanding of their structure-function relationships [11][12][13].…”