Influence of Thermal Annealing on PCDTBT:PCBM Composition Profiles. Issue 5 (11th November 2013)

• Record Type: Journal Article
• Authors: Synooka, Olesia; Eberhardt, Kai‐Rudi; Singh, Chetan Raj; Hermann, Felix; Ecke, Gernot; Ecker, Bernhard; von Hauff, Elizabeth; Gobsch, Gerhard; Hoppe, Harald
• Is Part Of: Advanced energy materials. Volume 4:Issue 5(2014:May)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2013-11-11
• Subjects: Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201300981
• Languages: English
• ISSNs: 1614-6832

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>A variety of measurement techniques including photothermal deflection spectroscopy (PDS), auger electron spectroscopy (AES), (sub–bandgap) external quantum efficiency (EQE), and impedance spectroscopy are applied to poly[N‐900‐hepta‐decanyl‐2, 7‐carbazole‐alt‐5, 5‐(40, 70‐di‐2‐thienyl‐20, 10, 30‐benzothiadiazole (PCDTBT)/[6, 6]‐phenyl C₇₁ butyric acid methyl ester (PC₇₁BM) films and devices to probe the stability under thermal annealing. Upon annealing, solar cell performance is drastically decreased for temperatures higher than 140 °C. Detailed investigation indicate changes in polymer:fullerene interactions resulting in the formation of a polymer wetting layer upon annealing at temperatures higher than 140 °C. Upon device completion this wetting layer is located close to the metal electrode and therefore leads to an increase in recombination and a decrease in charge carrier extraction, providing an explanation for the reduced fill factor (FF) and power conversion efficiency (PCE).</p> </abstract>