A photovoltaic device includes one or more features that taken alone or in combination enhance its efficiency. Some embodiments may comprise a tandem solar device in which a top PV cell is fabricated upon a front transparent substrate, that also serves as the top encapsulating substance. The top PV cell including the front encapsulating substance is then bonded (e.g., using adhesive) to a bottom PV cell in order to complete the tandem device. Using the same transparent, insulating element as both front encapsulating substance and a substrate for fabricating the top PV cell, obviates to the need to provide a separate structure (with resulting interfaces) to perform the latter role. For tandem and non-tandem PV devices, a Through-Substrate-Via (TSV) structure may extend through an insulating substrate in order to provide contact with an opposite side (e.g., back electrode). Embodiments may find particular use in fabricating shingled perovskite photovoltaic solar cells.

A homogeneous coating solution for forming a light-absorbing layer of a solar cell, the homogeneous solution including: at least one metal or metal compound selected from the group consisting of a group 11 metal, a group 13 metal, a group 11 metal compound and a group 13 metal compound; a Lewis base solvent; and a Lewis acid.

Photovoltaic cells, photovoltaic devices, and methods of fabrication are provided. The photovoltaic cells include a transparent substrate to allow light to enter the photovoltaic cell through the substrate, and a light absorption layer associated with the substrate. The light absorption layer has opposite first and second surfaces, with the first surface being closer to the transparent substrate than the second surface. A passivation layer is disposed over the second surface of the light absorption layer, and a plurality of first discrete contacts and a plurality of second discrete contacts are provided within the passivation layer to facilitate electrical coupling to the light absorption layer. A first electrode and a second electrode are disposed over the passivation layer to contact the plurality of first discrete contacts and the plurality of second discrete contacts, respectively. The first and second electrodes include a photon-reflective material.

Methods are provided for fabricating photovoltaic cell contacts, which include: providing a block copolymer layer above an electrical contact layer of the photovoltaic cell, the block copolymer layer being self-assembled by phase segregation to include multiple structures of a first polymer material surrounded, at least in part, by a second polymer material; selectively etching the block copolymer layer to remove the multiple structures, forming holes in the block copolymer layer; and using the holes in the block copolymer layer to facilitate providing electrical contacts between a light absorption layer of the photovoltaic cell and the electrical contact layer. For instance, the holes in the copolymer layer may be used in etching a passivation layer over the electrical contact layer to form nano-sized contact openings in the passivation layer to the contact layer. Once provided, the cell's light absorption material forms contacts extending through the contact openings in the passivation layer.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution.

The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.

A method for forming a back contact on an absorber layer in a photovoltaic device includes forming a two dimensional material on a first substrate. An absorber layer including CuZnSnS(Se) (CZTSSe) is grown over the first substrate on the two dimensional material. A buffer layer is grown on the absorber layer on a side opposite the two dimensional material. The absorber layer is exfoliated from the two dimensional material to remove the first substrate from a backside of the absorber layer opposite the buffer layer. A back contact is deposited on the absorber layer.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

A method of fabricating a color tunable thin film photovoltaic device includes depositing a layer of a semiconducting compound configured to exhibit a photovoltaic effect, and depositing a buffer layer over the layer of the semiconducting compound. Depositing transparent conducting oxides (TCO) over the buffer layer is followed by selecting two or more layers of optically transparent materials such that constructive interference among wavelengths reflected by the buffer layer, the TCO, and the two or more layers results in a desired exhibited color and depositing the two or more layers of the optically transparent materials above the TCO.

A method for fabricating a photovoltaic device includes forming a polycrystalline absorber layer including CuZnSnS(Se) (CZTSSe) over a substrate. The absorber layer is rapid thermal annealed in a sealed chamber having elemental sulfur within the chamber. A sulfur content profile is graded in the absorber layer in accordance with a size of the elemental sulfur and an anneal temperature to provide a graduated bandgap profile for the absorber layer. Additional layers are formed on the absorber layer to complete the photovoltaic device.