An Innovative Postdeposition Annealing Approach Producing Centimeter‐Scale In₂O₃/In₂(TeO₃)₃ Bulk Heterojunction Thin Film for Room‐Temperature Persistent Photoconductivity

Persistent photoconductivity holds great significance to a variety of interesting applications. However, persistent photoconductivity devices based on large‐scale thin films produced by a facile and efficient technology have rarely been achieved so far. In this work, centimeter‐scale In₂O₃/In₂(TeO₃)₃ bulk heterojunction thin films are prepared via an innovative and convenient two‐step approach, an initial pulsed‐laser deposition followed by a postdeposition annealing process. A prototype optoelectronic device is fabricated and it exhibits pronounced persistent photoconductivity with positive dependence on both the source–drain voltage and incident power density. This device also shows photoresponse to incident light with wavelengths from ultraviolet to red, revealing great potential for practical device applications such as optoelectronic memory and imaging. A physical model in agreement with the observed phenomena is built to qualitatively illustrate the occurrence of the persistent photoconductivity in the bulk heterojunction system. In addition, the facile two‐step approach is further applied to flexible mica substrates and the persistent photoconductivity is maintained upon tens of bending cycles, which not only demonstrates potential for wearable device but also provides tunable and extended focus range for the photoexcitation. These findings provide an innovative and universal scenario for the development of persistent photoconductivity.