Bi2S3 nanocrystals are employed as an n-type, non-toxic, inorganic, solution-processed semiconductor in thin film solar cells. The first solution processed-inorganic p-n junction based on p-type PbS QDs and n-type Bi2S3 nanocrystals with both phases contributing to photo-carrier generation is demonstrated. The reported devices show a power conversion efficiency of 1.6% for 860 nm PbS QDs and over 1% for 1300 nm PbS QDs.