Nanowall shaped Bi2S3 films were prepared by chemical bath deposition in which ammonium citrate and thioacetamide were used as chelating reagent and sulfur source, respectively. The nanowall Bi2S3 films show large-surface-area nanowall shaped morphology. It is found that the pH value (pH = 6 or pH = 6.5) of the solution is a crucial parameter to obtain the nanowall shaped Bi2S3 films. The composition of the nanowall Bi2S3 films is close to the stoichiometric ratio of Bi2S3. The absorption edge of the nanowall shaped Bi2S3 films is located at around 900 nm, indicating that the optical bandgap of the Bi2S3 films is around 1.4 eV. The nanowall Bi2S3 films show obvious photo-sensitivity. The photo-to-dark conductivity ratios of the nanowall Bi2S3 films prepared at pH = 6 and pH = 6.5 are all around 50. This value is around five times than that of the non-nanowall shaped Bi2S3 films which is prepared at pH = 7. (C) 2011 Elsevier B. V. All rights reserved.