▎ 摘　　要

Large area graphene films with varying growth time thicknesses were synthesized by chemical vapor deposition (CVD) on copper foil and transferred to other substrates for characterization and photovoltaic applications. Scanning tunneling microscopy, Raman spectroscopy, and imaging show films with high crystallinity, low defect density, I-2D/I-G ratio of 0.52-2.26, and the presence of continuous graphene sheets with optical transparency of 75.7%-96.8%. The use of CVD graphene sheets as counter electrode in dye-sensitized solar cells was explored. The short circuit current density (J(sc)), the open circuit current (V-oc), the fill factor (FF), and the overall conversion efficiency under AM 1.5, 100 mW cm(-2) illumination are 12.7 mA/cm(2), 544.8 mV, 57.5% and 3.8%, respectively.