Third-order nonlinear optical properties of polymethine-based materials: a theoretical investigation

Polymethines;Cyanines;Computational;Theoretical;Nonlinear optics;All-optical switching

Gieseking, Rebecca Lynn ; Sherrill, C. David Chemistry and Biochemistry Bredas, Jean-Luc Marder, Seth R. Perry, Joseph W. Kippelen, Bernard ; Sherrill, C. David

University:Georgia Institute of Technology

Department:Chemistry and Biochemistry

关键词: Polymethines;    Cyanines;    Computational;    Theoretical;    Nonlinear optics;    All-optical switching;   

Others  :  https://smartech.gatech.edu/bitstream/1853/53570/1/GIESEKING-DISSERTATION-2015.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Organic π-conjugated molecules and materials with large real parts and small imaginary parts of the third-order polarizability are of great interest for all-optical switching applications. In this dissertation, we use quantum-chemical and molecular-dynamics approaches to investigate the structure-property relationships that influence the nonlinear optical properties of π-conjugated molecules and materials. We begin with an overview of nonlinear optics, focusing in particular on the electronic properties of linear π-conjugated systems and some of the important problems that have limited device applications of these molecules to date. This is followed by a brief review of the computational methods employed in these studies.We then turn to the main results of the dissertation. Chapter 3 describes the structural dependence of the transition dipole moment between the first two polymethine excited states. Chapter 4 discusses the relationship between BLA, which depends on the geometric structure, and BOA, which probes electronic structure. Chapter 5 describes the benchmarking of computational methods to describe the symmetry-breaking of long polymethines and preliminary evidence regarding the role of vibrational modes in symmetry-breaking. Chapter 6 explains the negative third-order polarizability of tetraphenylphosphate and analogous systems. Chapter 7 focuses on molecular-dynamics studies of polymethine aggregation, particularly the relationships between chemical structure and the geometric and electronic structures of aggregates. Finally, Chapter 8 provides a synopsis of the work and discussion of further directions.