CuInSe2 (CIS) Thin Film Solar Cells by Electrostatic Spray Deposition

Abstract

In this paper, we demonstrate, for the first time, the manufacture of a CuInSe2 thin film whose absorber layer is coated using an electrostatic spray deposition (ESD) technique; its complete transformation into a working device with measured conversion efficiency is presented. ESD is superior to pneumatic spraying because it produces nano-scaled, self-dispersive (non-agglomerating), highly wettable (electrowetting) and adhesive droplets to yield a uniform coating on a substrate. Furthermore, ESD's extremely low material consumption rate holds promises for practical use in the solar cell industry. Copper and indium salts are added to various solvents, which are electrostatically sprayed onto a molybdenum-coated soda-lime glass substrate. The effect of substrate temperature on the thin film characteristics is examined. Our cell is completed by adding CdS and ZnO layers onto the CuInSe2 absorber layer. Light illuminated current-density voltage (J-V) characteristics demonstrate a power conversion efficiency of eta = 1.75% +/- 0.09 with an open-circuit voltage of V-OC = 0.23 V, a short-circuit current density of J(SC) = 21.72 mA/cm(2), and fill factor of FF = 0.34. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.jes113086] All rights reserved.