Two novel distyryl-boradiazaindacene dyes with dimethylaminophenyl and pyridyl appendages, display opposite spectral shifts on protonation with trifluoroacetic acid in organic solvents. This bidirectional switching of the dyes can be shown to be directly related to ICT donor and acceptor characteristics of the dyes. Thus, it has been demonstrated that the switching behavior of the red to NIR emitting dyes can be altered by simple structural modifications.

ABSTRACT Bridgeless Active Power Factor Correction Using a Current Fed Push Pull Converter Jeramie Seth Bianchi Switched Mode Power Supplies have become increasingly popular for efficient methods of delivering power to an assortment of electronic devices. This thesis proposes a method of using a current fed push pull converter to provide active power factor correction and rectification in a single stage. While most AC-DC converters utilize a bridge rectifier to convert AC-DC and then perform DC-DC conversion, the proposed circuit will utilize its output diodes to perform rectification, thus eliminating the need for a bridge rectifier. This circuit will also inherently provide power factor correction because the input current has a continuous path for current flow due to the current fed topology where no time exists for both switches to be off. Through analog circuitry for the controller, multiple methods of AC main switching are tested, including isolation techniques using optocouplers, to prove the most efficient way to control a bidirectional switch. Simulations with PSPICE and hardware implementation of the design prove that alternative methods to provide quality power conversion for Switched Mode Power Supplies are available. Keywords: Active Power Factor Correction, Current Fed Push Pull Converter, SMPS, Bidirectional Switching, IGBT, Bridgeless Rectification