Spray-assisted silar deposition of cadmium sulphide quantum dots on metal oxide films for excitonic solar cells I. Concina a, * , N. Memarian a, b , G.S. Selopal a , M.M. Natile c , G. Sberveglieri a , A. Vomiero a a SENSOR Laboratory, CNR-IDASC & Brescia University, Via Branze 45, 25133 Brescia, Italy b Physics Department, Semnan University, Semnan, Iran c CNR-ISTM and Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy highlights graphical abstract  Application of spray deposition to SILAR quantum dots generation is presented.  Enhanced optical density of CdS quantum dots on TiO 2 is achieved.  Smaller nanocrystal sizes were sys- tematically obtained.  Improved functional features of quantum dot sensitized solar cells were recorded. article info Article history: Received 8 March 2013 Received in revised form 22 April 2013 Accepted 9 May 2013 Available online 20 May 2013 Keywords: Spray deposition SILAR Semiconductor-sensitized solar cells Quantum dot growth kinetics abstract The proof of principle of the successful application of spray deposition to the SILAR (successive ionic layer absorption and reaction) technique, one of the most effective strategies to sensitized TiO 2 scaffold with QDs, is demonstrated. Systematically improved optical features of the materials (higher optical density together with reduced nanocrystal sizes) as well as of the functional performances of QD solar cells (photoconversion efficiency, fill factor, short circuit current, open circuit voltage) sensitized via SD-SILAR, with respect to traditional SILAR sensitization based on impregnation, are demonstrated. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction Inorganic semiconductor nanocrystals (NCs), also known as quantum dots (QDs) have attracted a remarkable interest over the last two decades as appealing materials to be exploited in a variety of domains [1e3]. This attention is especially motivated by their optical and electronic properties, easily tunable through the mod- ulation of their dimensions. The first paper dealing with their preparation appeared in 1993 [4] and since then many efforts have been carried out devoted to both increase the basic knowledge on these systems and the ways to exploit them. In particular, in the field of third generation photovoltaics (PV), semiconductor QDs appear as the ultimate frontier as light har- vesters [3], since they have band gap easily tunable with sizes, they can energetically sensitize metal oxides, they can expand the solar spectrum region in which light is collected [5] and they could in principle overcome the QueissereShockley limit, thanks to the claimed multiexciton generation effect, the presence of intraband transitions and other processes, which are not present in single * Corresponding author. E-mail address: isabella.concina@ing.unibs.it (I. Concina). Contents lists available at SciVerse ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour 0378-7753/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jpowsour.2013.05.012 Journal of Power Sources 240 (2013) 736e744