title: Enhanced Ultraviolet Stability of Air-Processed Polymer Solar Cells by Al Doping of the ZnO Interlayer.
abstract: Photostability of organic photovoltaic devices represents a key requirement for the commercialization of this technology. In this field, ZnO is one of the most attractive materials employed as an electron transport layer, and the investigation of its photostability is of particular interest. Indeed, oxygen is known to chemisorb on ZnO and can be released upon UV illumination. Therefore, a deep analysis of the UV/oxygen effects on working devices is relevant for the industrial production where the coating processes take place in air and oxygen/ZnO contact cannot be avoided. Here we investigate the light-soaking stability of inverted organic solar cells in which four different solution-processed ZnO-based nanoparticles were used as electron transport layers: (i) pristine ZnO, (ii) 0.03 at %, (iii) 0.37 at %, and (iv) 0.8 at % aluminum-doped AZO nanoparticles. The degradation of solar cells under prolonged illumination (40 h under 1 sun), in which the ZnO/AZO layers were processed in air or inert atmosphere, is studied. We demonstrate that the presence of oxygen during the ZnO/AZO processing is crucial for the photostability of the resulting solar cell. While devices based on undoped ZnO were particularly affected by degradation, we found that using AZO nanoparticles the losses in performance, due to the presence of oxygen, were partially or totally prevented depending on the Al doping level.
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR) - Istituto per lo Studio dei Materiali Nanostrutturati (ISMN) , Via P. Gobetti, 101, 40129 Bologna, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Prosa
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR) - Istituto per lo Studio dei Materiali Nanostrutturati (ISMN) , Via P. Gobetti, 101, 40129 Bologna, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Tessarolo
authors.affiliation: Laboratory MIST E-R , Via P. Gobetti, 101, 40129 Bologna, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Bolognesi
authors.affiliation: Aix-Marseille Université, CNRS , CINaM UMR 7325, 13288 Marseille, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Margeat
authors.affiliation: Department of Chemistry and Chemical Engineering, Polymer Technology, Chalmers University of Technology , Goteborg SE-412 96, Sweden.|Ian Wark Research Institute, Future Industries Institute, University of South Australia , Mawson Lakes, South Australia 5095, Australia.
authors.forename: Desta
authors.initials: D
authors.lastname: Gedefaw
authors.affiliation: Aix-Marseille Université, CNRS , CINaM UMR 7325, 13288 Marseille, France.
authors.forename: Meriem
authors.initials: M
authors.lastname: Gaceur
authors.affiliation: Aix-Marseille Université, CNRS , CINaM UMR 7325, 13288 Marseille, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Videlot-Ackermann
authors.affiliation: Department of Chemistry and Chemical Engineering, Polymer Technology, Chalmers University of Technology , Goteborg SE-412 96, Sweden.|Ian Wark Research Institute, Future Industries Institute, University of South Australia , Mawson Lakes, South Australia 5095, Australia.
authors.forename: Mats R
authors.initials: MR
authors.lastname: Andersson
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR) - Istituto per lo Studio dei Materiali Nanostrutturati (ISMN) , Via P. Gobetti, 101, 40129 Bologna, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Muccini
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR) - Istituto per la Sintesi Organica e la Fotoreattività (ISOF) , Via P. Gobetti, 101, 40129 Bologna, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Seri
authors.affiliation: Aix-Marseille Université, CNRS , CINaM UMR 7325, 13288 Marseille, France.
authors.forename: Jörg
authors.initials: J
authors.lastname: Ackermann
keywords: ZnO nanoparticles; aluminum-doped ZnO; degradation; interlayer; oxygen chemisorption; photostability; polymer solar cells