Real-time Photoluminescence Studies of Thin Film Formation in Organic Solar Cells

Published

February 29, 2016

Author(s)

Sebastian Engmann, Felicia A. Bokel, Hyun W. Ro, Dean M. DeLongchamp, Lee J. Richter

Abstract

We present a method to study the structural evolution of organic bulk-heterojunctions via real-time, in-situ, steady state photoluminescence (PL). In-situ PL, in combination with real-time transmission and reflection measurements, allowed us to quantitatively describe the progression of intimate mixing during blade coating of two OPV systems: the common model system poly(3-hexylthiophene-2,5-diyl) / phenyl-C61-butyric-acid-methyl ester ( P3HT / [60]PCBM), and the higher power conversion efficiency system 7,7’-(4,4bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b’]dithiophene-2,6-diyl)bis(6-fluoro-5-(5’-hexyl-[2,2’-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazaole), p-DTS(FBTTh2)2 / [70]PCBM. Evaluating the time dependence of the PL-intensity during drying using a 3D-random walk diffusion model allowed for the quantitative determination of the ratio of characteristic domain size to exciton diffusion length during solidification in the presence of processing additives 1-chloronaphtalene (CN), 1,8-octanedithiol (ODT) and 1,8-diiodooctane (DIO). In both cases the obtained results were in good agreement with the typically observed fibril widths and grain sizes, for P3HT and p-DTS(FBTTh2)2 respectively.

Citation

Advanced Energy Materials

Volume

6

Pub Type

Journals

Download Paper

https://doi.org/10.1002/aenm.201502011

Keywords

Photoluminescence, UV-Vis, In-situ, Bulk heterojunction, Polymer, Small-molecule, Fullerene

Citation

Engmann, S. , Bokel, F. , Ro, H. , DeLongchamp, D. and Richter, L. (2016), Real-time Photoluminescence Studies of Thin Film Formation in Organic Solar Cells, Advanced Energy Materials, [online], https://doi.org/10.1002/aenm.201502011 (Accessed October 14, 2025)