Nanomorphology of polythiophene-fullerene bulk-heterojunction films investigated by structured illumination optical imaging and time-resolved confocal microscopy

X-T Hao; L M Hirvonen; T A Smith

doi:10.1088/2050-6120/1/1/015004

Nanomorphology of polythiophene-fullerene bulk-heterojunction films investigated by structured illumination optical imaging and time-resolved confocal microscopy

Methods Appl Fluoresc. 2013 Jan 28;1(1):015004. doi: 10.1088/2050-6120/1/1/015004.

Authors

X-T Hao¹, L M Hirvonen, T A Smith

Affiliation

¹ School of Chemistry and ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Victoria 3010, Australia.

PMID: 29148439
DOI: 10.1088/2050-6120/1/1/015004

Abstract

Structured illumination microscopy (SIM) and time-resolved confocal fluorescence microscopy are applied to investigate the nanomorphology of thin films comprising typical blends of the conjugated polymer, poly (3-hexylthiophene) (P3HT), and [6, 6]-phenyl C₆₁-butyric acid methyl ester (PCBM), used for organic photovoltaic applications. SIM provides evidence for the presence of a thin emissive region around the crystalline regions of PCBM and at the tips of rod-like domains. The time-resolved measurements show that the emission surrounding the PCBM rods is longer lived than the bulk of the film. The two modes of microscopy provide complementary evidence indicating that electron-hole separation is inhibited between the polymer and the large PCBM-rich domains in these regions. We show here that structured illumination microscopy is a viable method of gaining additional information from these photovoltaic materials, despite their weak emission.