Oxide electron selective contacts for perovskite solar cells are provided. In one aspect, a method of forming a perovskite solar cell is provided. The method includes the steps of: depositing a layer of a hole transporting material on a substrate; forming a perovskite absorber on the hole transporting material; depositing an oxide electron transporting material on the perovskite absorber; and forming a top electrode on the oxide electron transporting material. Perovskite solar cells and tandem photovoltaic devices are also provided.

An optical data communication and power converter device includes a receiver circuit comprising an optical receiver. The optical receiver includes a photovoltaic device and a photoconductive device arranged within an area that is configured for illumination by a modulated optical signal emitted from a monochromatic light source of a transmitter circuit. The photovoltaic device is configured to generate electric current responsive to the illumination of the area by the modulated optical signal. The photoconductive device is configured to generate a data signal, distinct from the electric current, responsive to the illumination of the area by the modulated optical signal. A reverse bias voltage may be applied to the photoconductive device by the photovoltaic device, independent of an external voltage source. Related devices and methods of operation are also discussed.

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

A high efficiency configuration for a solar cell module comprises solar cells conductively bonded to each other in a shingled manner to form super cells, which may be arranged to efficiently use the area of the solar module, reduce series resistance, and increase module efficiency. The front surface metallization patterns on the solar cells may be configured to enable single step stencil printing, which is facilitated by the overlapping configuration of the solar cells in the super cells. A solar photovoltaic system may comprise two or more such high voltage solar cell modules electrically connected in parallel with each other and to an inverter. Solar cell cleaving tools and solar cell cleaving methods apply a vacuum between bottom surfaces of a solar cell wafer and a curved supporting surface to flex the solar cell wafer against the curved supporting surface and thereby cleave the solar cell wafer along one or more previously prepared scribe lines to provide a plurality of solar cells. An advantage of these cleaving tools and cleaving methods is that they need not require physical contact with the upper surfaces of the solar cell wafer. Solar cells are manufactured with reduced carrier recombination losses at edges of the solar cell, e.g., without cleaved edges that promote carrier recombination. The solar cells may have narrow rectangular geometries and may be advantageously employed in shingled (overlapping) arrangements to form super cells.

A light concentrator of an embodiment includes: a first high refractive index layer, a first low refractive index layer, and a second high refractive index layer stacked in sequence, wherein a surface on the first low refractive index layer side of the first high refractive index layer has a periodic concavoconvex region.

Systems, methods, and apparatus for light collection and conversion to electricity are disclosed herein. The disclosed method involves receiving, by at least one concentrating element (e.g., a lens), light from at least one light source, where the light comprises direct light and diffuse light. The method further involves focusing, by at least one concentrating element, the direct light onto at least one concentrator photovoltaic cell. Also, the method involves passing, by at least one concentrating element, the diffuse light onto at least one solar cell of an array of solar cells arranged on a flat plate, where at least one concentrator photovoltaic cell is bonded on top of at least one of the solar cells in the array. In addition, the method involves collecting, by at least one concentrator photovoltaic cell, the direct light. Further, the method involves collecting, by at least one solar cell, the diffuse light.

Described herein are non-stoichiometric perovskite ink solutions, comprising: a first composition of formula FA.sub.1-xCs.sub.xBX.sub.3; a second composition of CsX, FAX, REX.sub.3, or REX.sub.2; and one or more solvents; wherein x, X, RE, and B are as defined herein. Methods for preparing polycrystalline perovskite films using the non-stoichiometric ink solutions and the use of the films in large-size solar modules are additionally described.

Provided is a tandem photovoltaic device comprising: a top cell, a bottom cell, and a first light-trapping structure, in stacking, wherein a band-gap width of the top cell is larger than that of the bottom cell; and at least one of a second light-trapping structure located on a side of a shading surface of the bottom cell and a third light-trapping structure located on a side of a phototropic surface of the top cell; the three light-trapping structures are selected from metal or semiconductor material, and localized surface plasmons generated by the three light-trapping structures correspond to different peaks of light-wave response; and the three light-trapping structures form microstructures on a first cross section, average sizes d1, d2 and d3 of projections of the microstructures and average distances w1, w2 and w3 between the microstructures have relationships: $2{\left(\frac{w1}{w2}\right)}^2.Math.\frac{d2}{d1}16,\mathrm{and}/\mathrm{or}2{\left(\frac{w3}{w1}\right)}^2.Math.\frac{d1}{d3}16.$

A solar-cell module comprising a tandem solar cell and a controller that substantially optimizes the power output the tandem solar cell is disclosed. The tandem solar cell includes a first solar cell having a first energy bandgap and a second solar cell having a second energy bandgap, where the first and second solar cells are arranged such that light not absorbed by the first solar cell passes through it to the second solar cell to be absorbed. The controller controls an electrical parameter, such as current or voltage, of at least one of the first and second solar cells such that the electrical parameter is equal in both cells, thereby substantially optimizing the output power of the tandem solar cell.

The disclosure provides for a direct wafer bonding method including providing a bonding layer upon a first and second wafer, and directly bonding the first and second wafers together under heat and pressure. The method may be used for directly bonding an GaAs-based, InP-based, GaP-based, GaSb-based, or Ga(In)N-based device to a GaAs device by introducing a highly doped (Al)(Ga)InP(As)(Sb) layer between the devices. The bonding layer material forms a bond having high bond strength, low electrical resistance, and high optical transmittance.