Defect Processes in a PbS metal organic framework: A quantum-confined hybrid semiconductor

We report the effects of reduced dimensionality and organic networks on defect reactions in a hybrid solid of PbS (galena). Through first-principles calculations, we demonstrate that formation of the organic-inorganic network increases both the band gap and defect reaction energies. Remarkably, anion vacancies result in a localized defect center in both the bulk and hybrid materials, with high ionization energies deep in the band gap, while cation vacancies provide low energy shallow acceptor levels; the hybrid system will favor intrinsic p-type conductivity. The results demonstrate the feasibility of utilizing hybrid solids to engineer material properties for solar cell applications.