A modified polysulfide redox couple, (CH3)(4)N)(2)S/((CH3)(4)N)(2)S-n, was employed in CdS quantum dots (QDs) sensitized B/S co-doped TiO2 solar cell with NiS as counter electrode, followed by chemical bath deposition (CBD) in an organic solution to prepare the QDs-cell to ensure high wettability and superior penetration ability of the B/S co-doped TiO2 films, with the co-doping of B/S in TiO2, its band-gap was narrowed and significantly extended the light capture range, and an enhanced energy conversion efficiency of up to 3.6% was observed under AM 1.5 G illuminations, with a significantly high V-oc of 1,217 V, a high ff of 88.2% and a short-circuit photocurrent (J(sc)) of 335 mA cm(-2). (C) 2014 Elsevier B.V. All rights reserved.