skip to main content

Title: Transient electrically detected magnetic resonance spectroscopy applied to organic solar cells

The influence of light-induced paramagnetic states on the photocurrent generated by polymer:fullerene solar cells is studied using spin-sensitive techniques in combination with laser-flash excitation. For this purpose, we developed a setup that allows for simultaneous detection of transient electron paramagnetic resonance as well as transient electrically detected magnetic resonance (trEDMR) signals from fully processed and encapsulated solar cells. Combining both techniques provides a direct link between photoinduced triplet excitons, charge transfer states, and free charge carriers as well as their influence on the photocurrent generated by organic photovoltaic devices. Our results obtained from solar cells based on poly(3-hexylthiophene) as electron donor and a fullerene-based electron acceptor show that the resonant signals observed in low-temperature (T = 80 K) trEDMR spectra can be attributed to positive polarons in the polymer as well as negative polarons in the fullerene phase, indicating that both centers are involved in spin-dependent processes that directly influence the photocurrent.
Authors:
; ; ; ;  [1]
  1. Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195 Berlin (Germany)
Publication Date:
OSTI Identifier:
22486391
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BINDING ENERGY; CHARGE CARRIERS; DETECTION; ELECTRON SPIN RESONANCE; ELECTRONS; EXCITATION; EXCITONS; FULLERENES; LASERS; ORGANIC SOLAR CELLS; PARAMAGNETISM; PHOTOCURRENTS; PHOTOVOLTAIC EFFECT; POLARONS; POLYMERS; SPECTRA; SPECTROSCOPY; SPIN; TEMPERATURE RANGE 0065-0273 K; VISIBLE RADIATION