Abstract: Techniques for gas analysis using a parallel dipole line (PDL) trap viscometer are provided. In one aspect, a gas analysis system is provided which includes: a PDL trap including: a pair of diametric cylindrical magnets, and a diamagnetic rod levitating above the magnets; and a motion detector for capturing motion of the diamagnetic rod. The motion detector can include a digital video camera positioned facing a top of the PDL trap so as to permit capturing video images of the diamagnetic rod and the system can include a computer for receiving and analyzing video images from the video camera. Methods for measuring gas viscosity and pressure using the PDL trap system are also provided.

Abstract: A magnetic trap is configured to arrange at least one diamagnetic rod. The magnetic trap includes first and second magnets on a substrate that forms the magnetic trap defining a template configured to self-assemble diamagnetic material. Each of the first and second magnets extends along a longitudinal direction to define a magnet length, and contact each other to define a contact line. The first magnet and the second magnet have a diametric magnetization in a direction perpendicular to the contact line and the longitudinal direction so as to generate a longitudinal energy potential that traps the diamagnetic rod along the longitudinal direction.

Abstract: Kesterite-based homojunction photovoltaic devices are provided. The photovoltaic devices include a p-type semiconductor layer including a copper-zinc-tin containing chalcogenide compound and an n-type semiconductor layer including a silver-zinc-tin containing chalcogenide compound having a crystalline structure the same as a crystalline structure the copper-zinc-tin containing chalcogenide compound.

Abstract: A photovoltaic device includes a substrate, a first electrode formed on the substrate and a p-type absorber layer including a chalcogenide compound. An n-type layer includes a zinc oxysulfide material having a sulfur content adjusted to match a feature of the absorber layer. A transparent contact is formed on the n-type layer.

Abstract: Techniques for solar cell electrical characterization are provided. In one aspect, a solar testing device is provided. The device includes a solar simulator; and a continuous neutral density filter in front of the solar simulator having regions of varying light attenuation levels ranging from transparent to opaque, the continuous neutral density filter having an area sufficiently large to filter all light generated by the solar simulator, and wherein a position of the continuous neutral density filter relative to the solar simulator is variable so as to control a light intensity produced by the device. A solar cell electrical characterization system and a method for performing a solar cell electrical characterization are also provided.

Abstract: A photovoltaic device includes a first contact and a hybrid absorber layer. The hybrid absorber layer includes a chalcogenide layer and a semiconductor layer in contact with the chalcogenide layer. A buffer layer is formed on the absorber layer, and a transparent conductive contact layer is formed on the buffer layer.

Abstract: A rotating magnetic field Hall apparatus is provided and includes first and second magnets disposed in a master-slave configuration, a device-under-test (DUT) stage interposable between the first and second magnets on which a DUT is disposable in first or second orientations for Hall measurement or photoelectromagnetic (PEM) testing, respectively, controllers disposed to center the DUT stage between the first and second magnets and orthogonal magnetic field sensors disposed aside lateral sides of the first magnet to facilitate positional initialization of the first and second magnets and to generate in-phase and out-of-phase reference signals for phase-sensitive or lock-in Hall signal detection. The system also includes software system to perform signal processing to yield the final Hall signal.

Abstract: A rotating magnetic field Hall apparatus is provided and includes first and second magnets disposed in a master-slave configuration, a device-under-test (DUT) stage interposable between the first and second magnets on which a DUT is disposable in first or second orientations for Hall measurement or photoelectromagnetic (PEM) testing, respectively, controllers disposed to center the DUT stage between the first and second magnets and orthogonal magnetic field sensors disposed aside lateral sides of the first magnet to facilitate positional initialization of the first and second magnets and to generate in-phase and out-of-phase reference signals for phase-sensitive or lock-in Hall signal detection. The system also includes software system to perform signal processing to yield the final Hall signal.

Abstract: A magnetic trap is configured to arrange at least one diamagnetic rod. The magnetic trap includes first and second magnets on a substrate that forms the magnetic trap defining a template configured to self-assemble diamagnetic material. Each of the first and second magnets extends along a longitudinal direction to define a magnet length, and contact each other to define a contact line. The first magnet and the second magnet have a diametric magnetization in a direction perpendicular to the contact line and the longitudinal direction so as to generate a longitudinal energy potential that traps the diamagnetic rod along the longitudinal direction.

Abstract: A photovoltaic device includes a first contact and a hybrid absorber layer. The hybrid absorber layer includes a chalcogenide layer and a semiconductor layer in contact with the chalcogenide layer. A buffer layer is formed on the absorber layer, and a transparent conductive contact layer is formed on the buffer layer.

Abstract: A method for self-aligning diamagnetic materials includes contacting first and second magnets together other along a contact line so as to generate a diametric magnetization that is perpendicular to the contact line. A diamagnetic rod is positioned with respect to the first and second magnets to levitate above the contact line of the first and second magnets.

Abstract: An apparatus for determining solar cell characteristics includes a quantum efficiency measurement tool configured to measure an external quantum efficiency of the solar cell and a reflectivity measurement tool configured to measure the reflectivity of the solar cell. The apparatus also includes a capacitance measurement tool configured to measure the capacitance of the solar cell and a processor configured to calculate a diffusion length of the solar cell based on the measured quantum efficiency, reflectivity and capacitance of the solar cell.

Abstract: A method for thermal exfoliation includes providing a target layer on a substrate to form a structure. A stressor layer is deposited on the target layer. The structure is placed in a temperature controlled environment to induce differential thermal expansion between the target layer and the substrate. The target layer is exfoliated from the substrate when a critical temperature is achieved such that the target layer is separated from the substrate to produce a standalone, thin film device.

Abstract: An apparatus for determining solar cell characteristics includes a quantum efficiency measurement tool configured to measure an external quantum efficiency of the solar cell and a reflectivity measurement tool configured to measure the reflectivity of the solar cell. The apparatus also includes a capacitance measurement tool configured to measure the capacitance of the solar cell and a processor configured to calculate a diffusion length of the solar cell based on the measured quantum efficiency, reflectivity and capacitance of the solar cell.

Abstract: A system for self-aligning diamagnetic materials includes first and second magnets contacting each other along a contact line and having a diametric magnetization perpendicular to the contact line and a diamagnetic rod positioned to levitate above the contact line of the first and second magnets.

Abstract: Tandem Kesterite-perovskite photovoltaic devices and techniques for formation thereof are provided. In one aspect, a tandem photovoltaic device is provided. The tandem photovoltaic device includes a bottom cell having a first absorber layer comprising copper, zinc, tin, and at least one of sulfur and selenium and a top cell connected in series with the bottom cell, the top cell having a second absorber layer comprising a perovskite material. A method of forming a tandem photovoltaic device is also provided.

Abstract: Vacuum annealing-based techniques for forming perovskite materials are provided. In one aspect, a method of forming a perovskite material is provided. The method includes the steps of: depositing a metal halide layer on a sample substrate; and vacuum annealing the metal halide layer and methylammonium halide under conditions sufficient to form methylammonium halide vapor which reacts with the metal halide layer and forms the perovskite material on the sample substrate. A perovskite-based photovoltaic device and method of formation thereof are also provided.

Abstract: A system for self-aligning diamagnetic materials includes first and second magnets contacting each other along a contact line and having a diametric magnetization perpendicular to the contact line and a diamagnetic rod positioned to levitate above the contact line of the first and second magnets.

Abstract: A method for self-aligning diamagnetic materials includes contacting first and second magnets together other along a contact line so as to generate a diametric magnetization that is perpendicular to the contact line. A diamagnetic rod is positioned with respect to the first and second magnets to levitate above the contact line of the first and second magnets.

Abstract: A method for analyzing a material-under-test includes levitating a free-floating magnet between a material-under-test and a diamagnet and a mounted magnet, such that the diamagnet is positioned between the mounted magnet and the free-floating magnet, measuring a rotation rate of the free-floating magnet over time, and calculating at least one of a conductivity and resistivity of the material-under-test based on the measured rotation rate of the free-floating magnet over time.