Enhanced photoconductivity of layered $\mathrm{Mn}(\mathrm{IV}){\mathrm{O}}_2$ containing protonated Mn(IV) vacancy defects has been recently demonstrated, suggesting new technological possibilities for photoelectric conversion based on visible light harvesting. Using spin-polarized density functional theory, we provide the first direct evidence that such defects can indeed facilitate photoconductivity by (i) reducing the band-gap energy and (ii) separating electron and hole states. Our results thus support the proposition that nanosheet ${\mathrm{MnO}}_2$ offers an attractive new material for a variety of photoconductivity applications.

• Received 5 October 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.146601