Thin Solid Films, Vol.517, No.7, 2443-2447, 2009
Nanostructured solar cell by spray pyrolysis: Effect of titania barrier layer on the cell performance
ZnO nanostructured solar cells with CuInS(2) absorber layer were prepared by chemical spray method. In order to increase chemical stability of ZnO nanorods against dissolution in the next steps of the cell preparation, and reduce the electrical shorts between the front and back contacts, an amorphous TiO(2) layer was deposited on ZnO nanorods by ALD or sol-gel spray technique. The thicknesses of the layer (<= 5 nm by spray and <= 1 nm by ALD), which did not impede the collection of carriers, were determined. TiO(2) thicknesses above these optimal values led to s-shaped I-V curves, causing the decrease in solar cell efficiency from 2.2 to 0.7% due to the formation of an additional junction blocking charge carrier transport in the device under forward bias. Nanostructured cells suffered from somewhat higher interface recombination but showed still two times higher current densities (similar to 10 mA/cm(2)) than the planar devices did. (C) 2008 Elsevier B.V. All rights reserved.
Keywords:ZnO nanorod;Solar cell;ZnO-TiO(2) core shell;Chemical spray pyrolysis;ALD;Sol-gel spray;Electrical properties