Antimony doped tin oxide (ATO - Sn0.92O2:Sb0.08) nanoparticles were synthesized by different chemical routes such as Hydrothermal (HT), Sol-gel (SG) and Sonochemical (SC) methods. The XRD pattern of the samples shows that Sb ion successfully incorporated into Sn lattice without altering the crystal structure. Optical spectral analysis of the samples indicates more absorption in the visible region. The vibrational modes of the ATO nanoparticles were characterized by FTIR spectra. DSSCs were fabricated with the as-prepared ATO nanoparticles from different routes, Eosin-Y dye, I−/I3− redox couple as electrolyte. I–V characteristics of the as fabricated devices were recorded to estimate the efficiency of the device. Our results indicate the DSSC fabricated using the hydrothermally synthesized ATO nanoparticle gives good efficiency (η = 4.15%) comparing to the DSSCs fabricated using NPs synthesized via other methods. Hence, hydrothermally prepared material is to be considered as a suitable optical window material for DSSCs.