Organic semiconductors have attracted considerable attention due to their applications in low-cost (opto)electronic devices. The most successful organic materials for applications that rely on charge carrier generation, such as solar cells, utilize blends of several types of molecules. In blends, the local environment strongly influences exciton and charge carrier dynamics. However, relationship between nanoscale features and photophysics is difficult to establish due to the lack of necessary spatial resolution. We use functionalized fluorinated pentacene (Pn) molecule as single molecule probes of intermolecular interactions and of the nanoscale environment in blends containing donor and acceptor molecules. Single Pn donor (D) molecules were imaged in PMMA in the presence of acceptor (A) molecules using wide-field fluorescence microscopy. Two sample configurations were realized: (i) a fixed concentration of Pn donor molecules, with increasing concentration of acceptor molecules (functionalized indenflouorene or PCBM) and (ii) a fixed concentration of acceptor molecules with an increased concentration of the Pn donor. The D-A energy transfer and changes in the donor emission due to those in the acceptor- modified polymer morphology were quantified. The increase in the acceptor concentration was accompanied by enhanced photobleaching and blinking of the Pn donor molecules. To better understand the underlying physics of these processes, we modeled photoexcited electron dynamics using Monte Carlo simulations. The simulated blinking dynamics were then compared to our experimental data, and the changes in the transition rates were related to the changes in the nanoscale environment. Our study provides insight into evolution of nanoscale environment during the formation of bulk heterojunctions.

Document Type

Conference Proceeding

Publication Date


Notes/Citation Information

Published in Proceedings of SPIE, v. 10101, Organic Photonic Materials and Devices XIX, article 101010K, p. 1-8.

Copyright 2017 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

Nicole Quist , Rebecca Grollman , Jeremy Rath , Alex Robertson, Michael Haley, John Anthony, Oksana Ostroverkhova, "Single molecule-level study of donor-acceptor interactions and nanoscale environment in blends," Proc. SPIE 10101, Organic Photonic Materials and Devices XIX, 101010K (16 February 2017). DOI: https://doi.org/10.1117/12.2251276

The copyright holder has granted the permission for posting the article here.

Digital Object Identifier (DOI)


Funding Information

This work was supported by the National Science Foundation through grant DMR-1207309. N. Q. also acknowledges the SPIE Student Travel Grant Program, Oregon State University Graduate School and Oregon State University President’s Commission on the Status of Women.

Related Content

Conference Presentation available online.