Abstract: A secondary reflector for receiving light from a plurality of primary reflectors that includes a reflecting surface having a length aligned along a first axis (z), where a cross-section of the reflecting surface in a plane perpendicular to the first axis (z) forms a curve comprising a concave section positioned between a first endpoint and a second endpoint, at least a portion of the concave section is accurately approximated by a polynomial equation, an aperture is formed by a straight line connecting the first endpoint to the second endpoint, and the concave section is configured to focus a plurality of beams of light passing through the aperture onto a focal point.

Abstract: A photovoltaic system for generating electrical power on farmland while minimizing reduction of solar radiation incident on ground due to shadowing, including a photovoltaic module having a first photovoltaic face defining a first plane, a normal axis extending from the first plane, a first pivot axis extending through the photovoltaic module, a second pivot axis extending through the photovoltaic module, at least one motor operationally connected to pivot the photovoltaic module about at least one pivot axis, and an electronic controller operationally connected to at least one motor. An incident solar ray strikes the photovoltaic module at an angle of incidence defined as an intersection of the incident solar ray and the normal axis. The electronic controller sends signals to the at least one motor to maintain the angle of incidence as close as possible to ninety degrees.

Abstract: A solar module assembly includes a frame having an upper portion encompassing an area and a mid portion disposed below the upper portion. A plurality of solar panels is arranged in a string, sandwiched between two transparent panes forming a single string panel. The solar panels occupy less than the area of the upper portion. Each of the plurality of solar panels has a pair of opposing edges. A reflector is mounted on the mid portion to reflect light selectively.

Abstract: A 3D printed three-dimensional photovoltaic system that allows for the absorption of solar energy from various angles. The solar structure has a plurality of solar cells in a substantially flat 3D polygon solar frame or substantially flat mountainous 3D solar frame having an uneven surface and a reflective surface positioned underneath the solar frame to reflect light. The plurality of solar cells are oriented at various angles with respect to said reflective surface. The plurality of solar cells are configured to receive sunlight.

Abstract: A system and method for array level terrain based backtracking includes a tracker configured to collect solar irradiance and attached to a rotational mechanism for changing a plane of the tracker and a controller in communication with a rotational mechanism. The controller is programmed to determine a position of the sun at a first specific point in time, retrieve height information, execute a shadow model based on the retrieved height information and the position of the sun, determine a first angle for the tracker; collect an angle for each tracker in a plurality of trackers in an array; adjust the first angle based on executing the shadow model with the first angle and the plurality of angles associated with the plurality of trackers; transmit instructions to the rotational mechanism to change the plane of the tracker to the adjusted first angle.

Abstract: A solar module includes a plurality of photovoltaic cells and a sandwich structure on which the plurality of photovoltaic cells is structurally supported. The sandwich structure includes top and bottom structural plates and an open-cell inner material located between the top and bottom structural plates.

Abstract: A detector includes a housing having a window. A detection engine is configured to detect an event external to the housing. A battery is connected to the detection engine and configured to supply power thereto. A solar cell is configured to generate electricity when exposed to a light received through the window. The solar cell is arranged in the housing and electrically connected to the battery.

Abstract: A solar device includes a first string of first solar wafers, wherein a plurality of the first solar wafers each overlap with at least one vertically adjacent solar wafer from the first string. Additionally, the solar device includes a second string of second solar wafers, wherein a plurality of the second solar wafers each overlap with at least one vertically adjacent solar wafer from the second string, wherein a plurality of the first solar wafers overlap with one or more of the plurality of second solar wafers to electrically connect horizontally adjacent solar wafers in parallel.

Abstract: A III-V semiconductor pixel X-ray detector, including an absorption region of a first or a second conductivity type, at least nine semiconductor contact regions of the second conductivity type arranged in a matrix along the upper side of the absorption region, and optionally a semiconductor contact layer of the first conductivity type, a metallic front side connecting contact being arranged beneath the absorption region, and a metallic rear side connecting contact being arranged above each semiconductor contact region, and a semiconductor passivation layer of the first or the second conductivity type. The semiconductor passivation layer and the absorption region being lattice-matched to each other. The semiconductor passivation layer being arranged in regions on the upper side of the absorption region. The semiconductor passivation layer having a minimum distance of at least 2 ?m or at least 20 ?m with respect to each highly doped semiconductor contact region.

Abstract: A solar cell and a photovoltaic module including the solar cell. The solar cell includes: a semiconductor substrate including a first surface and a second surface opposite to each other; a first dielectric layer located on the first surface; a first N+ doped layer located on a surface of the first dielectric layer; a first passivation layer located on a surface of the first N+ doped layer; a first electrode located on a surface of the first passivation layer; a second dielectric layer located on the second surface; a first P+ doped layer located on a surface of the second dielectric layer; a second passivation layer located on a surface of the first P+ doped layer; and a second electrode located on a surface of the second passivation layer.

Abstract: A method for producing a photovoltaic solar cell, including the method steps: A. providing at least one solar cell precursor having at least one base and at least one emitter; B. providing a metal film on a back side of the solar cell precursor, so that the metal film is electrically conductively connected to the base or the emitter, the metal film being formed as an integral component of the back side contact and the solar cell being terminated on the back side. The at least one cell connection region on at least one side of the metal film overhangs the edge of the solar cell precursor by at least 1 mm, preferably by at least 3 mm.

Abstract: A method of manufacturing a cold plate includes forming a fluid circuit on a build surface in a layer-by-layer fashion from a build material. The fluid circuit includes a plurality of peripheral walls, each of the plurality of peripheral walls at least partially defining a primary channel, a longitudinally one of the peripheral walls being formed to include apertures configured to permit excess build material to pass therethrough. A central wall of the fluid circuit at least partially defines the primary channel and a plurality of secondary channels fluidly connected to the primary channel. The method further includes removing excess build material through the apertures.

Abstract: This light absorbing device includes: a light reflecting layer; a dielectric layer disposed on the light reflecting layer; and a plurality of metal nanostructures disposed on the dielectric layer. A portion of each of the plurality of metal nanostructures is buried in the dielectric layer and another portion thereof is exposed to the outside.

Abstract: A fabrication method for stretchable/conformable electronic and optoelectronic circuits and the resulting circuits. The method may utilize a variety of electronic materials including, but not limited to Silicon, GaAs, InSb, Pb Se, CdTe, organic semiconductors, metal oxide semiconductors and related alloys or hybrid combinations of the aforementioned materials. While a wide range of fabricated electronic/optoelectronic devices, circuits, and systems could be manufactured using the embodied technology, a hemispherical image sensor is an exemplary advantageous optoelectronic device that is enabled by this technology. Other applications include but are not limited to wearable electronics, flexible devices for the internet-of-things, and advanced imaging systems.

Abstract: A portable solar photovoltaic (PV) electricity generator module comprises a plurality of smart power slat (SPS) units, each SPS unit comprising a plurality of solar cells electrically connected together based on a specified cell interconnection design, and, N at least one power maximizing integrated circuit collecting electricity generated by the plurality of solar cells. The plurality of SPS units are mechanically connected such that the SPS units can be retracted for volume compaction of the module, and can be expanded for increasing PV electricity generation by the module. The module can be used as part of an electric power supply with a maximum power point tracking (MPPT) power optimizer, storage battery and leads to connect to a load. The load can be AC or DC.

Abstract: An actuator assembly for a solar tracking system. The actuator assembly includes a gearbox housing and a gearbox cover, a motor, and a lead screw. The gearbox housing and gearbox cover cooperate to define an internal chamber for receiving a gear assembly. The motor is mounted to the gearbox housing and is operatively connected to the gear assembly. The lead screw is operatively attached to the gear assembly and mounted inside an inner tube. A thrust bearing assembly is disposed between the gear assembly and the lead screw, with a portion of a thrust bearing nut being positioned within the thrust bearing assembly. A castle nut engages the thrust bearing nut, with the locking washer being frictionally engaged with the castle nut in an interlocking manner. An inner tube is mounted with in an outer tube for linear movement with respect to the outer tube.

Abstract: A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell that lies in the path of the incoming light beam.

Abstract: A semiconductor wafer is as wide as the industry standard width A (presently 156 mm+/?1 mm) and is longer than the industry standard A by at least 1 mm and as much as the standard equipment can reasonably accommodate, presently approximately 3-20 mm and potentially longer, thus, gaining significant additional surface area for sunlight absorption. Modules may be composed of a plurality of such larger wafers. Such wafers can be processed in conventional processing equipment that has a wafer retaining portion of industry standard size A and a configuration that also accommodates a wafer with a perpendicular second edge longer than A by at least 1 and typically 3-20 mm. Wet bench carriers and transport and inspection stations can be so used.

Abstract: There is provided a light trapping dynamic photovoltaic module having a module surface configured to be exposed to solar rays, including a plurality of photovoltaic cell stacks configured adjacent to each other throughout the module surface, wherein each photovoltaic cell stack comprises a plurality of photovoltaic cells. Further, a plurality of reflective strips are placed in between each of the photovoltaic cell stacks for continuously reflecting incident solar rays from one reflective strip to another until absorbed by a photovoltaic cell among said plurality of photovoltaic cells, wherein the incident solar rays are continuously reflected through a mirror phenomenon, wherein the incident solar rays are additionally reflected by front and back panels of the dynamic photovoltaic module, thereby trapping incident solar rays within boundaries of the dynamic photovoltaic module for conversion into electrical energy. Also disclosed is a method of manufacturing the light trapping photovoltaic module.

Abstract: In one example, a sensor comprises a photovoltaic device. The photovoltaic device comprises a core having a shape that is at least partially spherical, an absorber disposed over the core, and a transparent conductor disposed over the absorber. Other examples and related methods are also disclosed herein.

Abstract: A solar cell panel using a back contact solar cell is disclosed. The solar cell panel includes a front substrate, a back sheet positioned opposite the front substrate, a plurality of solar cells positioned between the front substrate and the back sheet and connected to one another by a plurality of conductive lines electrically connecting two adjacent solar cells, an encapsulant covering the plurality of solar cells, and at least one blocking portion blocking the plurality of conductive lines that is otherwise visible between the solar cells from being visually seen. The at least one blocking portion is positioned between a back surface of the front substrate and the encapsulant.

Abstract: The present disclosure relates to compound parabolic concentrators. In one implementation, a compound parabolic concentrator may include a parabolic array having a base, a side wall, and an aperture for receiving light and a dielectric layer having a refractive index. In another implementation, a stacked compound parabolic concentrator may include a parabolic array having a base, a side wall, and an aperture for receiving light and multiple dielectric layers within the array. Each dielectric layer may have a refractive index, and the refractive index may decrease with each dielectric layer moving from the base of the parabolic array to the light receiving aperture.

Abstract: Systems, methods, and computer-readable media are described herein to model divergent beam ray paths between locations on a roof (e.g., of a structure) and modeled locations of the sun at different times of the day and different days during a week, month, year, or another time period. A graphical user interface allows for visualization of the modeled ray paths and graphical manipulation of the resolution and parameters of the modeling process.

Abstract: A distributed energy conversion system may include one or more DC power sources and two or more inverters to convert DC power from the power sources to AC power. The AC power from the two or more inverters may be combined to provide a single AC output. A module may include one or more photovoltaic cells and two or more inverters. An integrated circuit may include power electronics to convert DC input power to AC output power and processing circuitry to control the power electronics. The AC output power may be synchronized with an AC power distribution system.

Abstract: A stacked monolithic multi-junction solar cell having at least four subcells, wherein the band gap increases starting from the first subcell in the direction of the fourth subcell, each subcell has an n-doped emitter and a p-doped base, the emitter and the base of the first subcell each are formed of germanium, all following subcells each have at least one element of main group III and V of the periodic table, all subcells following the first subcell are formed lattice-matched to one another, a semiconductor mirror having a plurality of doped semiconductor layers with alternately different refractive indices is placed between the first and second subcell, the semiconductor layers of the semiconductor mirror are each formed n-doped and each have a dopant concentration of at most 5·1018 cm?3, the semiconductor mirror is placed between the first subcell and the first tunnel diode.

Abstract: A two-piece truss leg with an articulating coupler for an A-frame-shaped truss foundation system for single-axis trackers. The coupler is attached to the head of each screw anchor to enable it to be driven. A connection portion extends above the coupler and is received within an open end of an upper leg to allow the upper leg to be misaligned with respect to it corresponding screw anchor.

Abstract: A vehicle lamp includes a light emitting unit having a light source and a light guide lens, the light guide lens has an incidence section from which light emitted from the light source enters inside of the light guide lens, and an emission section from which the light entered inside of the light guide lens from the incidence section is emitted to an outside, the incidence section has a plurality of stepped portions which are radially arranged about an optical axis of a light emitted from the light source and which are inclined toward an advancing direction of the light, and the stepped portions have a form in which incidence surfaces, from which a light radially emitted from the light source enters inside of the light guide lens while parallelizing the entered light, and connecting surfaces, which are adjacent to the incidence surfaces, are alternately arranged in a radial direction.

Abstract: Solar tracking installation includes first movement assembly which functionally engages with the primary axis shaft to cause rotation of the primary axis shaft around the primary axis for moving the plurality of planar modules of solar collector elements in a first rotational direction around the primary axis. The installation further includes a second movement assembly which functionally engages with the secondary movement member to cause tilting of each of the plurality of planar modules of solar collector elements around each respective pivotal mount. In this way the movement of the multitude of solar collection elements is a combination of the rotation of first movement assembly and the tilting motion caused by the second movement assembly.

Abstract: The present invention provides a hybrid, concentrating photovoltaic-solar thermal (CPV/T) system and components thereof, and methods for converting solar energy to electricity at high efficiencies while capturing and storing solar thermal energy for later deployment.

Abstract: The present disclosure provides systems and methods for improved bifacial solar modeling. A method may comprise measuring an albedo of a surface on which an array of bifacial solar modules is disposed and setting an albedo parameter of a bifacial gain model. The method may further comprise measuring a backside irradiance of the array and setting a backside irradiance parameter. The method may further comprise setting a shed transparency parameter using the measured backside irradiance and a geometric model of the array. The method may further comprise setting a rear shading parameter using a shading model of the array. The method may further comprise computing an expected bifacial gain of the array. The method may further comprise determining an actual bifacial gain of the array. The method may further comprise setting a rear mismatch parameter to minimize a loss function of the expected bifacial gain and the actual bifacial gain.

Abstract: Artificial satellite “Card-Sat” comprising a frame (1), an upper cover (2) and a lower cover (3), both covers (2, 3) being fixed to the frame (1), the frame (1), the upper cover (2) and the lower cover (3) defining a substantially paralelepipedic chamber (5), the satellite further comprising solar cells (6) fixed to the outer surface, in respect to the chamber (5), of the upper cover (2) and of the lower cover (3), and an avionics system (7), integrated on the inner surface, in respect to the chamber (5), of at least one of the upper cover (2) or the lower cover (3).

Abstract: An antenna housing configured to house a wireless antenna unit. The antenna housing defines an interior space sized to receive the antenna unit. Inlet and outlet ducting extend through a sidewall of the housing to connect to an internal cooling duct of the antenna unit allowing air to be drawn from outside the housing, through the antenna unit and expelled out of the hosing without intermingling with air in the interior of the housing. Additional airflow paths extend around side and/or rear surfaces antenna unit to provide additional cooling.

Abstract: A solar panel system is assembled into a three-dimensional volume with the solar cell(s) positioned on an inward facing surface to collect sunlight and reflect sunlight from different angles as the sun passes overhead. Embodiments may be mounted into the interior of a building with a top end of the module being positioned on or proximate a roof surface and disposed to collect sunlight into the module interior below the roof line. Some embodiments may be pyramidal shaped. Outdoor mounting of the solar panel module includes embodiments that may be held in a frame and rail mounted system.

Abstract: A photovoltaic array of photovoltaic solar cells; a smart dynamic programmable circuit breaker for electrically providing a pulsed 100 microseconds duration short circuit to the photovoltaic array electrical outputs, wherein a response time for the smart dynamic programmable circuit breaker is more than 1 millisecond when responding to a short circuit; a computer program comprising instructions that when executed by the processor perform functions that control the smart dynamic programmable circuit breaker, the computer program comprising: instructions to command the smart dynamic programmable circuit breaker to initiate the 100 microsecond pulsed short circuit; instructions to measure a current magnitude and current rise time of the smart photovoltaic system outputs during the 100 microsecond pulsed short circuit; and instructions to select a behavior curve from a plurality of smart dynamic programmable circuit breaker behavior curves 10% above the current magnitude and current rise time during the pulsed sh

Abstract: A photoelectric conversion device includes: a fluorescent light guide plate that has a plate-shaped structure in which fluorescent substances that absorb sunlight and emit fluorescent light are dispersed and which is formed of a material having a refractive index different from a refractive index of an outside, the fluorescent light emitted from the fluorescent substances being concentrated onto an edge surface to be emitted when the sunlight is incident; a first photoelectric cell configured to generate power by being irradiated with the sunlight; a lens layer configured such that light incident from an outer surface is concentrated onto the first photoelectric cell; a second photoelectric cell configured to generate power by being irradiated with the fluorescent light emitted from the edge surface of the fluorescent light guide plate; and power output units configured to extract power obtained in the photoelectric cells.

Abstract: Example systems may include one or both of a light emitter and a light receiver, and an optical filter. The optical filter may include a wavelength selective scattering layer configured to scatter visible light. The optical filter may include a wavelength selective reflecting layer having a predetermined transmission band configured to compensate for a color deviation. The optical filter may include a broadband reflecting layer having a predetermined reflection band configured to compensate for a color deviation. The optical filter may include a low-index layer configured to reduce a color deviation in light emitted by the light emitter or received by the light receiver. The wavelength selective scattering layer may include nanoparticles dispersed in a binder, wherein the ratio of the nanoparticles to the binder by weight is at least 50%. Example articles may include example optical filters.

Abstract: According to the present disclosure, techniques related to manufacturing and applications of power photodiode structures and devices based on group-III metal nitride and gallium-based substrates are provided. More specifically, embodiments of the disclosure include techniques for fabricating photodiode devices comprising one or more of GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, structures and devices. Such structures or devices can be used for a variety of applications including optoelectronic devices, photodiodes, power-over-fiber receivers, and others.

Abstract: A modular solar skid includes a base including a skid, a panel support structure extending from the skid, at least one solar panel coupled to the panel support structure, and at least one enclosure coupled to the skid. The at least one enclosure is located within a cavity defined between the skid and the panel support structure.

Abstract: A wafer-scale satellite bus and a manner of making the same include using wafer reconstruction techniques to stack functional diced circuits onto each other and bond them. The disclosed techniques allow for a variety of functions in each die, including providing, without limitation: ground-based communications, attitude and propulsion control, fuel tanks and thrusters, and power generation. The wafers are initially manufactured according to a common wafer design that provides electrical and power interconnects, then different wafers are further processed using subsystem-specific techniques. The circuits on differently-processed wafers are reconstructed into a single stack using e.g. wafer bonding. Surface components are mounted, and the circuitry is diced to form the final satellites. Mission-specific functions can be incorporated, illustratively by surface-mounting, to the bus at an appropriate stage of assembly, on-wafer circuitry or instrument packages for performing these functions.

Abstract: A display position adjusting apparatus includes a processor and an arcuate bracket. The arcuate bracket includes a first arcuate rod and a second arcuate rod that are disposed perpendicular to each other. The display is disposed on the second arcuate rod. The display is connected to the second arcuate rod through the first connector and configured to move along the second arcuate rod through the first connector under a control of the processor. The second arcuate rod is connected to the first arcuate rod through a second connector, and configured to move along the first arcuate rod through the second connector under the control of the processor.

Abstract: A solar thermophotovoltaic system has a heat exchanger containing a heat exchange fluid, and a thin-film integrated spectrally-selective plasmonic absorber emitter (ISSAE) in direct contact with an outer surface of the heat exchanger, the ISSAE including an ultra-thin non-shiny metal layer that is strongly absorbing in a solar spectral range and strongly reflective in an infrared spectral range. The metal layer has an inner surface in direct contact with an outer surface of the heat exchanger. A photovoltaic cell support structure with an inner surface in a concentric configuration partially surrounds the ISSAE; and an airgap separates the support structure and the outer surface of the metal layer. Photovoltaic cells are arranged on a portion of the inner surface of the support structure to receive emissions from the ISSAE, and a solar energy collector/concentrator allows solar radiation to impinge a portion of the metal layer.

Abstract: An improved solar power generation system, having at least one solar-array module. The solar cells in a solar-array module are interconnected in a crisscross matrix network configuration. The solar cells are a pre-sorted by the class of tolerance level of output power, such that the solar cells in each of the rows of solar cells are arranged in a steadily ascending (or steadily descending) order of the maximum power values that the solar cells are capable to provide, wherein the maximum power value of a solar cell in a particular row is higher or equal to the maximum power values of the previous (next, for steadily descending order) solar cells in the same row.

Abstract: The disclosure describes systems and methods for retrofitting a light fixture using a lens-fitted retrofit assembly. The lens-fitted retrofit assembly is attached anterior to the LED lamp engine. A lens-fitted retaining adapter of the lens-fitted retrofit assembly includes at least one curved portion that matches a radius of curvature of a lens holder of the light fixture. The lens-fitted retrofit assembly is held into the light fixture based at least in part on the lens-fitted retaining adapter and the lens holder.

Abstract: A system and method for determining a balance point of a building that has undergone or is about to undergo modifications (such as shell improvements) are provided. A balance point of the building before the modifications can be determined using empirical data. Total thermal conductivity of the building before and after the modifications is determined and compared. Indoor temperature of the building is obtained. The balance point temperature after the modifications can be determined using a result of the comparison, the temperature inside the building, and the pre-modification balance point temperature. Knowing post-modification balance point temperature allows power grid operators to take into account fuel consumption by that building when planning for power production and distribution. Knowing the post-improvement balance point temperature also provides owners of the building information on which they can base the decision whether to implement the improvements.

Abstract: Disclosed herein is a technique of configuring flexible photovoltaic tracker systems with high damping and low angle stow positions. Under dynamic environmental loads implementing a high amount of damping (e.g., greater than 25% of critical damping, greater than 50% of critical damping) or a very high amount of damping (e.g., 100% or greater of critical damping, infinite damping) enables the flexible tracker system to prevent problematic aeroelastic behaviors while positioned in a low stow angle. The disclosed technique is further applied to a prototyping process during wind tunnel testing.

Abstract: A multi-junction solar cell of an embodiment includes a first solar cell including a first photoelectric conversion device, a second solar cell including a plurality of second photoelectric conversion devices connected in series and having a back contact, and an insulating layer between the first solar cell and the second solar cell. A device isolation region is provided between the second photoelectric conversion devices connected in series.

Abstract: A solar cell and a photovoltaic module including the solar cell. The solar cell includes: a semiconductor substrate including a first surface and a second surface opposite to each other; a first dielectric layer located on the first surface; a first N+ doped layer located on a surface of the first dielectric layer; a first passivation layer located on a surface of the first N+ doped layer; a first electrode located on a surface of the first passivation layer; a second dielectric layer located on the second surface; a first P+ doped layer located on a surface of the second dielectric layer; a second passivation layer located on a surface of the first P+ doped layer; and a second electrode located on a surface of the second passivation layer.

Abstract: A multijunction solar cell including a metamorphic layer, and particularly the design and specification of the composition, lattice constant, and band gaps of various layers above the metamorphic layer in order to achieve reduction in “bowing” of the semiconductor wafer caused by the lattice mismatch of layers associated with the metamorphic layer.

Abstract: A connecting member set includes a first connecting member connected to one of a pair of solar cells, and a second connecting member connected to the other solar cell. The first connecting member and the second connecting member have a first planar portion and a second planar portion, respectively. The first planar portion and the second planar portion are layered on each other and electrically connected with each other. The first planar portion has at least one of a cut-out portion or an opening through which the second planar portion is exposed toward the first planar portion when the first planar portion and the second planar portion are layered on each other.

Abstract: A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom is provided. Each solar power station includes a plurality of satellite modules. The plurality of satellite modules each include a plurality of modular power generation tiles including a photovoltaic solar radiation collector, a power transmitter and associated control electronics. Numerous embodiments relate to efficient power generation tiles. In one embodiment, an efficient power generation tile includes: at least one photovoltaic material; and at least one concentrator that redirects incident solar radiation towards a photovoltaic material such that the photovoltaic material experiences a greater solar flux relative to the case where the photovoltaic material experiences unaltered solar radiation.