Effects of Nd-doping on optical and photovoltaic properties of barium titanate thin films prepared by sol–gel method

•We prepared Nd-doped BTO thin films by sol–gel method.•Addition of Nd to some extent can inhibit the grain growth.•Addition of Nd3+ ions can decrease band gap.•The remnant polarization of Nd-doped BTO thin films begins to increase and then decreases.•Photovoltaic properties of Nd-doped BTO thin films begin to increase then decrease. Nd-doped barium titanate thin films were prepared via sol–gel spin-coating method and effects of Nd content on microstructure, optical and photovoltaic properties have been investigated. The results show that Nd-doped barium titanate thin films are single tetragonal perovskite phase. Addition of neodymium to some extent can inhibit the grain growth. Substitution of Nd3+ ions for Ba2+ on A sites leads to the decrease of band gap. The remnant polarization begins to increase and reach the maximum and then decreases as Nd content increases. The short circuit photocurrent density, open circuit photovoltage and power conversion efficiency of Nd-doped barium titanate thin films begin to increase and reach the maximum and then decrease as Nd content increases.