%0 Journal Article
%T Hybrid TiO2 Solar Cells Produced from Aerosolized Nanoparticles of Water-Soluble Polythiophene Electron Donor Layer
%A Marshall L. Sweet
%A Joshua G. Clarke
%A Dmitry Pestov
%A Gary C. Tepper
%A James T. McLeskey Jr.
%J Journal of Solar Energy
%D 2014
%I 
%R 10.1155/2014/192812
%X Hybrid solar cells (HSCs) with water soluble polythiophene sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) thin films produced using electrospray deposition (ESD) were fabricated, tested, and modeled and compared to devices produced using conventional spin coating. A single device structure of FTO/TiO2/PTEBS/Au was used to study the effects of ESD of the PTEBS layer on device performance. ESD was found to increase the short circuit current density ( ) by a factor of 2 while decreasing the open circuit voltage ( ) by half compared to spin coated PTEBS films. Comparable efficiencies of 0.009% were achieved from both device construction types. Current-voltage curves were modeled using the characteristic solar cell equation and showed a similar increase in generated photocurrent with an increase by two orders of magnitude in the saturation current in devices from ESD films. Increases in are attributed to an increase in the interfacial contact area between the TiO2 and PTEBS layers, while decreases in are attributed to incomplete film formation from ESD. 1. Introduction Hybrid solar cells (HSCs) consist of an inorganic semiconducting electron acceptor and an organic polymer electron donor sandwiched between a transparent conducting oxide anode and a metal cathode. Polymer-based solar cells have attracted considerable attention due to low production cost, solution processing, and an array of different materials suitable for device fabrication [1¨C3]. HSCs take advantage of the high electron mobilities ( £¿cm2£¿V£¿1£¿s£¿1) [4, 5] in inorganic semiconductors to compensate for the poor hole mobilities in organic polymers (polythiophene polymers ¡Ö 0.00001¨C0.1£¿cm2£¿V£¿1£¿s£¿1) [6¨C9] which severely limit the electron diffusion length (~10£¿nm) [10, 11]. The interface between the inorganic semiconductor and the organic polymer in HSCs must be within one diffusion length of exciton generation to effectively separate excitons into holes and electrons. This presents a challenge to bilayer devices due to a limited interfacial contact area between the electron donor and acceptor layers. HSC devices have been designed with nanostructures (nanorods, nanoribbons, and interpenetrating layers) to increase the interfacial surface area [12¨C14]. An electrospray is a fine aerosol produced when electrical forces overcome surface tension forces in a liquid resulting in nebulization. While electrospray aerosols can be formed in a number of ways, the most common method is to apply a high electrical potential to a liquid inside of a metallic capillary tube. The liquid at the tip of
%U http://www.hindawi.com/journals/jse/2014/192812/