Embodiments of the invention generally relates to photovoltaic, thermophotovoltaic, and laser power beaming devices which convert solar light, thermal radiation, or laser radiation into electric power. Said devices have a reflective interference “greenhouse” filter placed in front of a semiconductor cell and a reflective mirror on the back of the cell. The front filter is transparent for high energy (short wavelength) photons, but traps low energy (long wavelength) photons emitted by photocarriers accumulated near the semiconductor bandgap. In the optimized PV device, the chemical potential of photoelectrons near semiconductor bandgap exceeds the chemical potential of photoelectrons above the photonic bandgap established by the filter (i.e., the device is in chemical nonequilibrium). The greenhouse filter reduces the emission losses, decreases the semiconductor cell thickness, and provides PV conversion with reduced nonradiative losses. Said device converts radiative energy into electricity in a more efficient way than conventional cells.

A method of producing a kesterite material of CZTS, CZTSe or CZTSSe type, including the steps of: a) preparing an acidic solution by dissolving copper and zinc salts in water in desired molar ratio, b) preparing a basic solution by dissolving an alkali metal stannate together with an alkali metal carbonate or an alkali metal hydrogen carbonate or an alkali metal hydroxide or a combination thereof, and optionally with an alkali metal selenate or an alkali metal selenite or a mixture thereof, c) carrying out a precipitation reaction by mixing the acidic and the basic solution, d) drying the precipitate thereby providing a precursor for the kesterite material, and e) sulfurizing the precursor of step d to provide the kesterite material. Also, a precursor for a kesterite material of CZTS, CZTSe or CZTSSe type.

In various embodiments, evaporation sources for deposition systems are heated and/or cooled via a fluid-based thermal management system.

A layer structure for a thin-film solar cell and production method are provided. The layer structure for the thin-film solar cell includes a photovoltaic absorber layer doped, at least in a region which borders a surface of the photovoltaic absorber layer, with at least one alkali metal. The layer structure has an oxidic passivating layer on the surface of the photovoltaic absorber layer, which is designed to protect the photovoltaic absorber layer from corrosion.

Disclosed herein are a recombination layer containing nanoparticles and an integrated tandem solar cell manufactured using the same. The integrated tandem solar cell includes a first solar cell having a form in which a rear electrode, a light absorption layer, and a buffer layer are stacked, a recombination layer formed on the buffer layer and including a triple layer structure which has first and second transparent conductive layers with a transparent conductive nanoparticle layer disposed therebetween, and a second solar cell disposed on and bonded to the recombination layer and including a perovskite layer.

A method for fabricating a photovoltaic device includes forming a polycrystalline absorber layer including Cu—Zn—Sn—S(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.

Improved high work function back contacts for solar cells are provided. In one aspect, a method of forming a solar cell includes: forming a completed solar cell having a substrate coated with an electrically conductive material, an absorber disposed on the electrically conductive material, a buffer layer disposed on the absorber, a transparent front contact disposed on the buffer layer, and a metal grid disposed on the transparent front contact; removing the substrate and the electrically conductive material using exfoliation, exposing a backside surface of the solar cell; depositing a high work function material onto the back side surface of the solar cell; and depositing a back contact onto the high work function material. A solar cell formed by the present techniques is also provided. Yield of the exfoliated device can be improved by removing bubbles from adhesive used for exfoliation and/or forming contact pads to access the metal grid.

An integrated kesterite (e.g., CZT(S,Se)) photovoltaic device and battery is provided. In one aspect, a method of forming an integrated photovoltaic device and battery includes: forming a photovoltaic device having a substrate, an electrically conductive layer, an absorber layer, a buffer layer, a transparent front contact, and a metal grid; removing the substrate and the electrically conductive layer from the photovoltaic device to expose a backside surface of the absorber layer; forming at least one back contact on the backside surface of the absorber layer; and integrating the photovoltaic device with a battery, wherein the integrating includes connecting i) a positive contact of the battery with the back contact on the backside surface of the absorber layer and ii) a negative contact of the battery with the metal grid on the transparent front contact. An integrated photovoltaic device and battery is also provided.

The invention relates to an optical detector (110) for an optical detection, in particular, of radiation within the infrared spectral range, specifically, with regard to sensing at least one optically conceivable property of an object (112). More particular, the optical detector (110) may be used for determining transmissivity, absorption, emission, reflectance, and/or a position of at least one object (112). Further, the invention relates to a method for manufacturing the optical detector (110) and to various uses of the optical detector (110). The optical detector (110) comprises an optical filter (114) having at least a first surface (116) and a second surface (118), the second surface (118) being located oppositely with respect to the first surface (116), wherein the optical filter (114) is designed for allowing an incident light beam (120) received by the first surface (116) to pass through the optical filter (114) to the second surface (118), thereby generating a modified light beam (122) by modifying a spectral composition of the incident light beam (120); a sensor layer (128) comprising a photosensitive material (130) being deposited on the second surface (118) of the optical filter (114), wherein the sensor layer (128) is designed to generate at least one sensor signal in a manner dependent on an illumination of the sensor layer (128) by the modified light beam (122); and an evaluation device (140) designed to generate at least one item of information provided by the incident light beam (120) by evaluating the sensor signal. The optical detector (110) constitutes an improved simple, cost-efficient and, still, reliable detector for detecting optical radiation, especially within the infrared spectral range, specifically with regard to sensing at least one of transmissivity, absorption, emission and reflectance. Hereby, the optical detector (110) is capable of effectively removing stray light as far as possible.

A voltage-matched solar module for converting incident solar radiation into electricity consisting of a plurality of wafer-sized multi-junction solar devices and wiring circuitry adjacent to a module-sized bottom substrate. Each solar device has at least two photovoltaic (PV) cells separated by electrically insulating transparent layers. The PV cells are aligned so as to overlap and are electrically connected to the wiring circuitry by conducting vias. The wiring circuitry includes a multiplicity of serial strings electrically connected in parallel and having substantially the same voltage. A method of producing the solar module is disclosed which utilizes an ALD/LPCVD tool for van der Waals epitaxy of 2D materials.