Film forming properties of electrosprayed organic heterojunctions

¹ CNISM – School of Science and Technology, Camerino University, via Madonna delle Carceri, 62032 Camerino (MC), Italy
² Physics Department, COMSATS Institute of Information Technology, Park Road Chak Shahzad, 44000 Islamabad, Pakistan
³ Linz Institute for Organic Solar Cells, No. 69, Altenberger Strase, 4040 Linz, Austria
⁴ Laboratoire IMS, UMR 5218 CNRS, ENSCBP, 16 avenue Pey-Berland, 33607 Pessac Cedex, France
⁵ Chemistry for Technologies Laboratory, University of Brescia, via Branze 38, 25123 Brescia, Italy
⁶ ISM-CNR-Area di Ricerca di Tor Vergata, via del Fosso del Cavaliere 100, 00133 Roma, Italy

^a e-mail: roberto.gunnella@unicam.it

Received: 26 February 2013
Revised: 10 May 2013
Accepted: 17 May 2013
Published online: 18 June 2013

Abstract

We used the electrospray deposition (ESD) method to fabricate organic photovoltaic devices with poly (3-hexyl-thiophene) (P3HT) and [6,6]-phenyl C₆₁ butyric acid methyl ester (PCBM) blends of different composition ratios and different organic solvent solution, namely chloroform (CLF) and dichlorobenzene (DCB). The morphology and crystallinity of the active layers were investigated by means of atomic force microscopy (AFM), two-dimensional X-ray diffraction (XRD²) and optical absorption, spreading light on the peculiarities of the present growth technique, involving much faster solvent evaporation and film forming processes, and comparatively much more ordered strutures with less need of thermal annealing processes. The power conversion efficiency (PCE) under AM 1.5G solar simulation obtained for devices deposited from DCB as compared to those deposited from CLF, showed significant improvement, in fair agreement with what was found by the overall characterization of the physical properties.