Provided are an interdigitated back contact solar cell (10,a,b,c), comprising a monocrystalline, n-doped wafer (101), a first contact area (40) which is formed by a first stack on the surface of said monocrystalline wafer (101), said first stack comprising a thin silicon oxide layer (201) and a highly n-doped polycrystalline silicon layer (301), and a second contact area (20) which is formed by a second stack on the same surface of said monocrystalline wafer (101) as said first stack, said second stack comprising a thin silicon oxide layer (202) and a highly p-doped polycrystalline silicon layer (701), wherein a p-doped monocrystalline silicon region (801) is located in a gap (30) between said first contact area (40) and said second contact area (20) and a method for producing such an interdigitated back contact solar cell (10,a,b,c).

An improved method of doping a workpiece is disclosed. The method is particularly beneficial to the creation of interdigitated back contact (IBC) solar cells. A patterned implant is performed on one surface of the workpiece. A self-aligned masking process is then performed, which is achieved by exploiting the changes in surface properties caused by the patterned implant. The masking process includes applying a coating that preferentially adheres to the previously implanted regions. A blanket implant is then performed, which serves to implant the portions of the workpiece that are not covered by the coating. Thus, the blanket implant is actually a complementary implant, doping the regions that were not implanted by the first patterned implant. The coating is then optionally removed from the workpiece.

There is provided a hydrogen production device which is high in the light use efficiency and can produce hydrogen with high efficiency without decreasing the hydrogen generation rate. The hydrogen production device according to the present invention comprises: a photoelectric conversion part having a light acceptance surface and a back surface; a first gas generation part and a second gas generation part provided on the back surface, wherein one of the first gas generation part and the second gas generation part is a hydrogen generation part to generate H.sub.2 from an electrolytic solution, and the other thereof is an oxygen generation part to generate O.sub.2 from the electrolytic solution, and at least one of the first gas generation part and the second gas generation part is plural, and the photoelectric conversion part is electrically connected to the first gas generation part and the second gas generation part so that an electromotive force generated by a light acceptance of the photoelectric conversion part is supplied to the first gas generation part and the second gas generation part.

Disclosed is a solar cell including a semiconductor substrate, a protective-film layer formed over one surface of the semiconductor substrate, a first conductive area disposed over the protective-film layer, the first conductive area being of a first conductive type and including a crystalline semiconductor, and a first electrode electrically connected to the first conductive area. The first conductive area includes a first portion disposed over the protective-film layer and having a first crystal grain size, and a second portion disposed over the first portion and having a second crystal grain size, which is greater than the first crystal grain size.

A method of forming an electrode, an electrode for a solar cell manufactured, and a solar cell, the method including forming a pattern of a finger electrode by: coating a composition for forming a first electrode that includes a conductive powder, an organic vehicle, and a first glass frit that is free of silver and phosphorus, and drying the coated composition for forming a first electrode; forming a pattern of a bus electrode by: coating a composition for forming a second electrode that includes a conductive powder, an organic vehicle, and a second glass fit that includes silver and phosphorus, and drying the coated composition for forming a second electrode; and firing the resultant patterns.

A dielectric coating material system for use in a single-sided back contact solar cell is disclosed. The material system serves to electrically isolate electrodes of opposite polarity types on the same side of a silicon-based solar call, and includes titanium and phosphorus.

Passivated contact structures and fabrication methods for back contact back junction solar cells are provided. According to one example embodiment, a back contact back junction photovoltaic solar cell is described that has a semiconductor light absorbing layer having a front side and a backside having base regions and emitter regions. A passivating dielectric insulating layer is on the base and emitter regions. A first electrically conductive contact contacts the passivating dielectric insulating layer together having a work function suitable for selective collection of electrons that closely matches a conduction band of the light absorbing layer. A second electrically conductive contact contacts the passivating dielectric insulating layer together having a work function suitable for selective collection of electrons that closely matches a valence band of the light absorbing layer.

A solar cell element comprises a silicon substrate, a passivation layer, a first conductive portion, an electrode, and a second conductive portion. The silicon substrate has a plurality of recessed portions in one main surface. The passivation layer is located on the one main surface and has holes in positions corresponding to the recessed portions. The first conductive portion is located in each of the holes. The electrode is connected to the first conductive portion while being located on the passivation layer, and contains aluminum. The second conductive portion is connected to each of the silicon substrate and the first conductive portion while being located in a region in each of the recessed portions, and contains aluminum and silicon. A void in which the second conductive portion is not located is present in the region in each of the recessed portions.

Fabrication methods for forming self aligned contacts for back contact solar cells are provided.

Systems and methods for fabricating a photovoltaic structure are provided. During fabrication, a patterned mask is formed on a first surface of a multilayer body of the photovoltaic structure, with openings of the mask corresponding to grid line locations of a first grid. Subsequently, a core layer of the first grid is deposited in the openings of the patterned mask, and a protective layer is deposited on an exposed surface of the core layer. The patterned mask is then removed to expose the sidewalls of the core layer. Heat is applied to the protective layer such that the protective layer reflows to cover both the exposed surface and sidewalls of the core layer.