A photovoltaic device includes a substrate structure and a p-type semiconductor absorber layer. A photovoltaic device may include a CdSeTe layer. A process for manufacturing a photovoltaic device includes forming a CdSeTe layer over a substrate. The process includes forming a p-type cadmium selenide telluride absorber layer.

A photovoltaic device includes a substrate structure and a p-type semiconductor absorber layer. A photovoltaic device may include a CdSeTe layer. A process for manufacturing a photovoltaic device includes forming a CdSeTe layer over a substrate. The process includes forming a p-type cadmium selenide telluride absorber layer.

A solar cell of an embodiment includes: a transparent substrate; a p-electrode on the substrate, the p-electrode including a first p-electrode containing an Sn-based metal oxide, a second p-electrode having an opening and consisting of a wiring containing a metal or graphene, and a third p-electrode containing an In-based metal oxide; a p-type light absorbing layer in direct contact with a surface of the first p-electrode on a side opposite to the second p-electrode side; an n-type layer provided on the p-type light absorbing layer; and an n-electrode provided on the n-type layer. The third p-electrode is provided to be present between the first p-electrode and the second p-electrode and to be in direct contact with an upper surface of the second p-electrode. An entire side surface of the second p-electrode is in direct contact with the first p-electrode.

A solar cell of an embodiment includes: a transparent substrate; a p-electrode on the substrate, the p-electrode including a first p-electrode containing an Sn-based metal oxide, a second p-electrode having an opening and consisting of a wiring containing a metal or graphene, and a third p-electrode containing an In-based metal oxide; a p-type light absorbing layer in direct contact with a surface of the first p-electrode on a side opposite to the second p-electrode side; an n-type layer provided on the p-type light absorbing layer; and an n-electrode provided on the n-type layer. The third p-electrode is provided to be present between the first p-electrode and the second p-electrode and to be in direct contact with an upper surface of the second p-electrode. An entire side surface of the second p-electrode is in direct contact with the first p-electrode.

Embodiments of a photovoltaic device are provided herein. The photovoltaic device can include a layer stack and an absorber layer disposed on the layer stack. The absorber layer can include a first region and a second region. Each of the first region of the absorber layer and the second region of the absorber layer can include a compound comprising cadmium, selenium, and tellurium. An atomic concentration of selenium can vary across the absorber layer. The first region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. The second region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. A ratio of an average atomic concentration of selenium in the first region of the absorber layer to an average atomic concentration of selenium in the second region of the absorber layer can be greater than 10.

Embodiments of a photovoltaic device are provided herein. The photovoltaic device can include a layer stack and an absorber layer disposed on the layer stack. The absorber layer can include a first region and a second region. Each of the first region of the absorber layer and the second region of the absorber layer can include a compound comprising cadmium, selenium, and tellurium. An atomic concentration of selenium can vary across the absorber layer. The first region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. The second region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. A ratio of an average atomic concentration of selenium in the first region of the absorber layer to an average atomic concentration of selenium in the second region of the absorber layer can be greater than 10.

A multi junction solar cell includes one or more upper cells and a thin-film, polycrystalline, low-bandgap bottom cell. A single-junction solar cell includes a polycrystalline semiconductor thin film, wherein a bandgap of the solar cell is greater than 1.2 eV or less than 1.2 eV, and the solar cell is configured to receive light through two surfaces, such that the bottom cell has bifacial operation.

A multi junction solar cell includes one or more upper cells and a thin-film, polycrystalline, low-bandgap bottom cell. A single-junction solar cell includes a polycrystalline semiconductor thin film, wherein a bandgap of the solar cell is greater than 1.2 eV or less than 1.2 eV, and the solar cell is configured to receive light through two surfaces, such that the bottom cell has bifacial operation.

According to the embodiments provided herein, a method for doping an absorber layer can include contacting the absorber layer with an annealing compound. The annealing compound can include cadmium chloride and a group V salt comprising an anion and a cation. The anion, the cation, or both can include a group V element. The method can include annealing the absorber layer, whereby the absorber layer is doped with at least a portion of the group V element of the annealing compound.

A thin-film solar cell contains: a lens material layer, a conductive contact layer, a first n-p semiconductor layer, a second n-p semiconductor layer, an insulation layer, a transparent conducting layer, a substrate, multiple first vias, multiple insulators, and multiple electrical conductors. A respective first via passes through the lens material layer, the conductive contact layer, and the first n-p semiconductor layer. The multiple insulators are accommodated in the respective first via, a top of a respective insulator is connected with the second n-p semiconductor layer, and a bottom of the respective insulator is connected with the insulation layer. The respective insulator includes a respective second via. A respective electrical conductor is formed in the respective second via, a top of the respective electrical conductor is connected with a respective transparent conducting layer, and a bottom of the respective electrical conductor is connected with the substrate.