Thin-film photovoltaic structures including semiconductor grain and oxide layers

A photovoltaic cell, comprising:

• one or more overlying electron-conducting layers each comprising one or more electron-conducting materials;
• one or more overlying hole-conducting layers each comprising one or more hole-conducting materials;
• and
• a plurality of photoactive conversion layers, each of the overlying photoactive conversion layers being disposed between the one or more overlying electron-conducting layers and the one or more overlying hole-conducting layers, each of the photoactive conversion layers comprising one or more distinct overlying semiconductor and oxide layers, each semiconductor and oxide layer comprising a multiplicity of semiconductor grains arranged in a distinct oxide matrix, wherein each of the semiconductor grains is substantially columnar, wherein each of the semiconductor grains has a height substantially equal to that of a thickness of the respective distinct semiconductor and oxide layer, and wherein the oxide matrix is dispersed at least at circumferential grain boundaries of the semiconductor grains;
• wherein in one or more of the photoactive conversion layers, the volumes of one or more of the semiconductor grains in one or more of the respective distinct semiconductor and oxide layers are different in the respective photoactive conversion layer resulting in different bandgaps of each of one or more of the distinct semiconductor and oxide layers in the respective photoactive conversion layer.