To optimize the visible light driven photovoltaic (PV) performance of orthorhombic n- type AgInS2 (AIS) fabricated thin film semiconductor (SC), in-situ incorporation of metallic gold [Au (0)] with very low concentrations (0.2-0.8%) has been done into AIS nanocrystal (NC). Sensitivity and stability of the SCs have been reported by chronoamperometric measurement. The optimized photocurrent density (7.1 mA/cm(2)) was obtained for AIS@Au (0.6%) and PV efficiency (eta) is increased by 3.30 times (approx.) with respect to the host MS SC. Most importantly the Incident Photon to current Conversion Efficiency (IPCE) measurement within the wavelength range of 450-750 nm reveals the definite wavelength of visible light energy corresponds to 560 nm at which about 80% efficiency was obtained for AIS@Au (0.6%). Powder X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) study, Transmission Electron Microscopic (TEM) analysis, UV-Vis absorption spectroscopy and Photoluminescence (PL) measurement indicate the presence as well as the importance of the metallic dopant in the hybrid nanomaterial. Mott-schottky plot reveals the flat band potential (0.22 V Vs. reference hydrogen electrode) for MS SC as well as majority carrier (here e(.)) density (N-D) 2.63 x 10(16) cm(-3) for AIS@Au (0.6%) which help to predict the higher PV efficiency of hybrid material fabricated thin film SC.