We present a new ternary semiconductor absorber material - Pb1-xSnxS - for solar cells. Pb1-xSnxS nanocrystals (NCs) were synthesized using the successive ionic layer adsorption reaction (SILAR) process. Energy-dispersive X-ray spectroscopy revealed the Sn ratio for a sample prepared with five SILAR cycles to be x = 0.55 (i.e. non-stoichiometric formula Pb0.45Sn0.55S). The optical spectra revealed that the energy gap E-g of the Pb1-xSnxS NCs decreased with an increasing number of SILAR cycles n, with E-g = 1.67 eV for the sample with n = 5. Liquid-junction Pb1-xSnxS quantum dot-sensitized solar cells were fabricated using the polysulfide electrolyte. The best cell yielded a short-circuit current density J(sc) of 10.1 mA/cm(2), an open circuit voltage of 0.43 V, a fill factor FF of 50% and an efficiency of 2.17% under 1 sun. The external quantum efficiency spectrum (EQE) covered a spectral range of 300-800 nm with a maximum EQE of similar to 67% at lambda = 650 nm. At the reduced light of 0.1 sun, the efficiency increased to 3.31% (with a normalized J(sc) = 17.7 mA/cm(2)) - a respectable efficiency for a new sensitizer. This work demonstrates that Pb1-xSnxS shows potential as a solar cell absorber. (C) 2016 Elsevier Inc. All rights reserved.