Bilayer electrolytes composed of a gadolinium-doped CeO2 (GDC) layer (similar to 6 mu m thickness) and an yttria-stabilized ZrO2 (YSZ) layer with various thicknesses (similar to 330 nm, similar to 440 nm, and similar to 1 mu m) were deposited by a pulsed laser deposition (PLD) technique for thin film solid oxide fuel cells (TFSOFCs). The bilayer electrolytes were prepared between a NiO-YSZ (60:40 wt.% with 7.5 wt.% carbon) anode and La0.5Sr0.5CoO3-Ce0.9Gd0.1O1.95 (50:50 wt.%) composite cathode for anode-supported single cells. Significantly enhanced maximum power density was achieved, i.e., a maximum power density of 188, 430, and 587 mW cm(-2) was measured in a bilayer electrolyte single cell with similar to 330 nm thin YSZ at 650, 700, and 750 degrees C, respectively. The cell with the bilayer electrolyte (YSZ similar to 330 nm) doubles the overall power output at 750 degrees C compared to that achieved in the GDC single layer cell. This signifies that the YSZ thin film serves as a blocking layer for preventing electrical current leakage in the GDC layer and also provides chemical, mechanical, and structural integrity in the cell, which leads to the overall enhanced performance. (C) 2011 Elsevier Ltd. All rights reserved.