Abstract: A photovoltaic device is presented. The photovoltaic device includes a layer stack; and an absorber layer is disposed on the layer stack. The absorber layer comprises selenium, wherein an atomic concentration of selenium varies across a thickness of the absorber layer. The photovoltaic device is substantially free of a cadmium sulfide layer.

Abstract: A lamp holder is disclosed lamp holder that will accept and make electrical contact with a lamp having a predetermined base and will accept, but not make electrical contact with lamps having other bases. A cavity (or central well) in the base (or floor) of the lamp socket is provided to accept a lamp configured with an extension extending from the base of the lamp and providing a vertically mounted electrical contact in the cavity that can only be contacted by a lamp contact that is placed at the end of the lamp base extension. A lamp lacking such an extension and a contact on such extension, cannot extend into and engage the contact in the cavity.

Abstract: The present invention relates to a lamp holder that can align a lamp with respect to a lamp holder and further secures the lamp against loosening caused by environmental vibrations (i.e., vibrations that are germane or inherent to the specific lighting application in which the lamp holder is installed). In one embodiment, a conductive sleeve is provided that includes a threaded portion for receiving an associated lamp; a positioning element located near the top portion of the conductive sleeve for engaging an alignment prong (or projection) of the associated lamp; and at least one vibration dampener formed in a portion of the conductive sleeve, wherein the vibration dampener and the positioning element ensure that the lamp will not vibrate excessively and/or become misaligned with respect to the holder.