ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of the introduction of an alcohol-soluble conjugated polyelectrolyte as cathode interlayer in solution-processed organic light-emitting diodes and photovoltaic devices

Francesco Carulli, Wojciech Mróz, Elisa Lassi, Cristina Sandionigi, Benedetta Squeo, Lorenzo Meazza, Guido Scavia, Silvia Luzzati, Mariacecila Pasini, Umberto Giovanella, and Francesco Galeotti

Istituto per lo Studio delle Macromolecole (CNR), Milan, Italy

E-mail: galeotti@ismac.cnr.it

Abstract: Interfacial engineering provides an important tool for optimizing the performances of optoelectronic devices. We show that poly[(2,7-(9,9′-dioctyl)fluorene)-alt-(2,7-(9,9′-bis(5″-trimethylammonium bromide)pentyl)fluorene)])], an alcohol-soluble π-conjugated polymer based on polyfluorene backbone and ammonium groups on the alkyl side chains, is capable of modifying the interface between the organic layer and the metal cathode in both organic solar cells and light-emitting diodes based on commercial materials and conventional architectures, improving their performances. The introduction of the cathode interlayer enhances the efficiency of a red-emitting phosphorescent OLED by 15% and decreases its turn-on voltage. The same polymer improves the power conversion efficiency of a PTB7/PC₇₁BM solar cell by 55% and shows a beneficial effect in terms of device stability.

Keywords: OLEDs ; OPV ; Cathode interlayer ; Polyelectrolytes ; Device optimization ; Solution processable devices 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0462-2

Chemical Papers 72 (7) 1753–1759 (2018)