Titania microstructure in a dye solar cell

A photovoltaic dye cell comprising:

• (a) a cell housing, said housing including an at least partially transparent cell wall;
• (b) an electrolyte, disposed within said housing, said electrolyte containing a redox charge transfer species;
• (c) an at least partially transparent electrically conductive layer disposed on a first interior surface of said cell wall, within the photovoltaic cell;
• (d) an anode disposed on said at least partially transparent electrically conductive layer, said anode including:
• (i) a sintered porous film containing sintered titania, said film disposed on a broad face of said electrically conductive layer, and adapted to make intimate contact with said electrolyte, and
• (ii) a dye, absorbed on a surface of said porous film, said dye and said porous film adapted to convert photons to electrons, by means of said charge transfer species;
• (e) a cathode disposed within said cell housing, substantially opposite said anode, said cathode including a catalytic surface disposed to fluidly contact said electrolyte;
• said sintered porous film having an overall average pore size (d50) falling within a range of 25 to 45 nanometers,
• said sintered porous film containing less than 700 ppm carbon,
• said sintered porous film having an at least bi-modal pore size distribution in which a first mode of said distribution has an average pore size of at most 23 nanometers, and in which a second mode of said distribution has an average pore size of at least 25 nanometers.

A photovoltaic dye cell comprising:

• (a) a cell housing, said housing including an at least partially transparent cell wall;
• (b) an electrolyte, disposed within said housing, said electrolyte containing a redox charge transfer species;
• (c) an at least partially transparent electrically conductive layer disposed on a first interior surface of said cell wall, within the photovoltaic cell;
• (d) an anode disposed on said at least partially transparent electrically conductive layer, said anode including:
• (i) a sintered porous film containing sintered titania, said film disposed on a broad face of said electrically conductive layer, and adapted to make intimate contact with said electrolyte, and
• (ii) a dye, absorbed on a surface of said porous film, said dye and said porous film adapted to convert photons to electrons, by means of said charge transfer species;
• (e) a cathode disposed within said cell housing, substantially opposite said anode, said cathode including a catalytic surface disposed to fluidly contact said electrolyte;
• said sintered porous film having an average pore size falling within a range of 25 to 45 nanometers,
• said sintered porous film containing less than 700 ppm carbon,
• said sintered porous film including at least one secondary material containing a metal,
• said metal having a concentration within a range of 10 ppm to 1000 ppm, said metal selected from the group of metals consisting of zinc, magnesium, and aluminum.

A method of producing a photovoltaic dye cell, the method comprising:

• (a) screen printing, onto a conductive layer of an at least partially transparent cell wall, a titania paste containing titania particles having an average particle size of less than 50 nanometers, and pore former particles having an average particle size of 20 nanometers to 300 nanometers;
• (b) subsequent to step (a), sintering said titania paste disposed on said conductive layer, at a temperature of at least 150° C., to produce a rigid, sintered titania layer;
• (c) subsequent to step (b), dissolving said pore former particles from said sintered layer to produce enlarged pores within said sintered titania layer;
• (d) staining said sintered titania layer with at least one dye, to produce a stained anode;
• (e) assembling said stained anode, a catalytic cathode and an electrolyte containing a charge transfer species;
• and
• (f) sealing said stained anode, said catalytic cathode and said redox electrolyte to produce the photovoltaic dye cell.