DISTRIBUTION OF THE EFFECTIVE CONJUGATION LENGTH OF POLYTHIOPHENE DETERMINED BY ITS ABSORPTION AND |χ⁽³⁾| SPECTRA

Abstract

We measured the absorption and |χ (3) | spectra around the excitonic resonance for Langmuir–Blodgett (LB) film of polythiophene derivative, poly(3-[2-((S)-2-methylbutoxy)ethyl]thiophene) at 10 K and room temperature. We derived a theoretical distribution function for the effective conjugation length taking the molecular weight distribution into consideration, and fitted the calculated absorption and |χ (3) | spectra to the experimental ones. From the fits, we estimated the average effective conjugation length to be 21 thiophene rings at 10 K, and 15 thiophene rings at room temperature.