Novel Donor-Acceptor Polymers for Solar Cells

ABSTRACT: The process of photo conversion in most opto-electronic devices includes transfer of absorbed solar energy to convert it into either chemical or electrical energy. Perylene and naphthalene dyes are characteristic n-type conjugated organic materials and are very attractive with great potential applications in the photonic field as they possess high stabilities, absorption capacities, and light emitting properties. The focus of this work is the synthesis, structure, photophysical, and electrochemical properties of oligomer dyes based on perylene and naphthalene chromophores, named, perylene-3,4,9,10-tetracarboxylic acid-Bis-(N,N_-Bis 2-[2-(2-{2-[2-(2- hydroxy-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethylpolyimide (EOPPI), naphthalene-1,4,5,8-tetracarboxylic acid-Bis-(N,N_-Bis 2-[2-(2-{2-[2-(2-hydroxyethoxy)- ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethylpolyimide (EONPI). Additionally, two previously synthesized n-type materials based on the same chromophores were considered to explore the electrochemical properties concerning photovoltaic devices. The compounds are characterized in detail by studying their optical, photophysical, thermal and electrochemical properties using the techniques IR, GPC, UV-vis, Fluorescence, DSC, TGA and Cyclic, squarewave voltammetries. Both oligomeric dyes exhibited attractive color tunability with different lightemitting properties. They possessed outstanding solubilities, molar absorption coefficients, thermal stabilities and electrochemical stabilities and reversibilities. The strong solvent dependent photophysical and electrochemical properties of EONPI, including the large shift of excimer emission maximum, makes the oligomer potential candidate for various photo sensing applications. Keywords: Perylene, naphthalene, solar cell, photovoltaic, color tunability. ……………………………………………………………………………………………………………………………………………………………………………………………………………………