Optoelectronic Properties of a Series of P3HT/ Dye Pairs

Dan Wang and Sam-Shajing Sun

Abstract

A series of polymer/dye composite pairs, where the same polymer Poly (3-hexylthiophene2,5-diyl) or P3HT paired with a series of three molecular dyes [Meso-Tetra(4-carboxyphenyl) porphine (TCPP), Ferriprotoporphyrin IX chloride (Hemin), and Protoporphyrin IX (Proto)] of different frontier orbitals and absorption coefficients are systematically investigated for potential optoelectronic conversion applications. A facile method to distinguish the charge and energy transfer contributions between emissive P3HT and dyes under certain conditions via concentration dependent photoluminescence (PL) is described. The experimental results from this study also revealed that the optoelectronic energy conversion efficiencies of the P3HT/dye based OE devices appear to be affected more critically by the P3HT/dye pair PL quenching than the optical absorption coefficients of the dyes, and that there appears to exist an optimal LUMO offset of P3HT/dye pair for most severe PL quenching or the best optoelectronic conversion efficiency. These study could be very useful for the design and development of next generation high efficiency soft materials based optoelectronic devices such as solar cells and photodetectors.