A doped photovoltaic device is presented. The photovoltaic device includes a semiconductor absorber layer or stack disposed between a front contact and a back contact. The absorber layer comprises cadmium, selenium, and tellurium doped with Ag, and optionally with Cu. The Ag dopant may be added to the absorber in amounts ranging from 510.sup.15/cm.sup.3 to 2.510.sup.17/cm.sup.3 via any of several methods of application before, during, or after deposition of the absorber layer. The photovoltaic device has improved Fill Factor and P.sub.MAX at higher P.sub.r (=I.sub.sc*V.sub.oc product) values, e.g. about 160 W, which results in improved conversion efficiency compared to a device not doped with Ag. Improved PT may result from increased I.sub.sc, increased V.sub.oc, or both.

Disclosed are methods for the surface cleaning and passivation of PV absorbers, such as CdTe substrates usable in solar cells, and devices made by such methods. In some embodiments, the method involves an anode layer ion source (ALIS) plasma discharge process to clean and oxidize a CdTe surface to produce a thin oxide layer between the CdTe layer and subsequent back contact layer(s).

Disclosed are methods for the surface cleaning and passivation of PV absorbers, such as CdTe substrates usable in solar cells, and devices made by such methods. In some embodiments, the method involves an anode layer ion source (ALIS) plasma discharge process to clean and oxidize a CdTe surface to produce a thin oxide layer between the CdTe layer and subsequent back contact layer(s).

The present disclosure relates to thin-film solar cells with improved efficiency and methods for producing thin-film solar cells having increased efficiency. In certain embodiments, thin-film solar cells having an efficiency of over 21%, over 20%, over 19%, over 15%, over 10%, etc. has been obtained using the methods of the disclosure. In certain aspects, the methods of the disclosure use passivation, passivating oxides, and/or doping treatments in increase the efficiency of the thin-film solar cells; e.g., CdTe-based thin-film solar cells.

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.

A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

A method of reclaiming cadmium material from photovoltaic (PV) modules is provided. The method includes submerging one or more portions of a PV module in a solution including non-distilled water, wherein the one or more portions of the PV module are submerged until cadmium material present on the PV module dissolves into the solution, boiling the solution until the dissolved cadmium material precipitates, and collecting the precipitated cadmium material.

A method of making a photovoltaic cell includes providing a metal oxide substrate. The substrate is at least translucent to light. The substrate is directed through a deposition chamber. A semiconductor is deposited over a first major surface of the substrate. The semiconductor includes a polycrystalline p-type layer. The semiconductor is exposed to a chlorine-containing compound or a chlorine molecule. A second electrode layer is provided over the semiconductor.