Annealed bulk crystals of barium titanate (BaTiO3) exhibit persistent photoconductivity (PPC) at room temperature. Samples were annealed in a flowing gas humid argon and hydrogen, with higher flow rate corresponding to larger PPC. When exposed sub-bandgap light, broad infrared (IR) absorption peak appears 5000 cm−1 (2 μm), attributed polaronic or free-carrier from electrons the conduction band....
