Donor-acceptor diethynylsilane oligomers: A second-order nonlinear optical material

• Published in: Journal of polymer science. Part B, Polymer physics Polymer physics, 2011-10, Vol.49 (19), p.1410-1419
• Main Authors: Machado, Ana E. De A., Souza, Leonardo A. De, Dos Santos, Hélio F., Almeida, Wagner B. De
• Format: Article
• Language: English
• Subjects: Applied sciences; Density functional theory; Derivatives; disubstituted diethynylsilane; Electrical, magnetic and optical properties; Exact sciences and technology; first hyperpolarizability; Mathematical analysis; NLO; Nonlinearity; Oligomers; Organic polymers; Partial differential equations; Physicochemistry of polymers; polydiethynylsilane; Properties and characterization; Solubility; Solvents
• ISSN: 0887-6266; 1099-0488; 1099-0488
• DOI: 10.1002/polb.22324

The interest in the study of oligomers has been motivated mainly because of their solubility in common solvents and also their capacity to be crystallized, which allowed for chemical processing leading to important applications in the area of material sciences. In this work, we carried out an investigation of polydiethynylsilane (PDES) decamers substituted with electron donor (D) and acceptor (A) groups, which is certainly of relevance, once PDES itself is known to display large third‐order optical susceptibility. Therefore, density functional theory calculations of static first hyperpolarizability (β) were performed using various functionals with the 6‐31G(d) basis set along with correlated MP2 calculation used as reference for comparison. The influence of A and D substituents on the magnitude of β was investigated by matching the acceptor (dicyanovinyl, nitrobenzene) and donor (propyl, propoxy, and phenylamine) groups attached at both ends of the oligomer. The largest β value was predicted for the derivative having the phenylamine and dicyanovinyl groups, which is around 30 times the relative value for the nonsubstituted decamer, what is a very impressive enhancement reported for the first time in the literature, strongly suggesting that disubstituted diethynylsilane decamers are potential building blocks for molecular‐based materials with second‐order nonlinear responses. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1410–1419, 2011 The search for molecules possessing a large value of first hyperpolarizability (β) is a key step toward the optimization of new materials for nonlinear optical response applications. By using density functional theory to screen suitable materials, it is suggested that disubstituted diethynylsilane decamers should have great potential as building blocks for molecular‐based materials with a second‐order nonlinear response.