A phototransistor device to act as an artificial photonic synapse includes a substrate and a graphene source-drain channel patterned on the substrate. A perovskite quantum dot layer is formed on the graphene source-drain channel. The perovskite quantum dot layer is methylammonium lead bromide material. A method of operating the phototransistor device as an artificial photonic synapse includes applying a first fixed voltage to a gate of the phototransistor and a second fixed voltage across the graphene source-drain channel. A presynaptic signal is applied as stimuli across the graphene source-drain channel. The presynaptic signal includes one or more pulses of light or electrical voltage. A current across the graphene source-drain channel is measured to represent a postsynaptic signal.

A contact to a semiconductor layer in a light emitting structure is provided. The contact can include a plurality of contact areas formed of a metal and separated by a set of voids. The contact areas can be separated from one another by a characteristic distance selected based on a set of attributes of a semiconductor contact structure of the contact and a characteristic contact length scale of the contact. The voids can be configured to increase an overall reflectivity or transparency of the contact.

Architectures for tandem solar cell including two thin films forming a top layer and a bottom layer. Such cells can be bi-facial. Exemplary materials used for the top layer are CIGS (CGS), perovskites (Sn and Ge), amorphous silicon (a-Si), copper oxide, tin sulfide, CZTS and III-V materials. For the bottom layer an inorganic film such as either silicon or germanium may be used. In general, the architecture includes of a glass, plastic or metal substrate and a buffer layer, either an oxide insulator or nitride conductor.

In the field of photoelectric devices, a visible light detector is provided with high-photoresponse based on a TiO.sub.2/MoS.sub.2 heterojunction and a preparation method thereof. The detector, based on a back-gated field-effect transistor based on MoS.sub.2, includes a MoS.sub.2 channel, a TiO.sub.2 modification layer, a SiO.sub.2 dielectric layer, Au source/drain electrodes and a Si gate electrode, The TiO.sub.2 modification layer is modified on the surface of the MoS.sub.2 channel. By employing micromechanical exfoliation and site-specific transfer of electrodes, the method is intended to prepare a detector by constructing a back-gated few-layer field-effect transistor based on MoS.sub.2, depositing Ti on the channel surface, and natural oxidation.

A photodetector device to act as an artificial photonic synapse includes a substrate and a perovskite quantum dot-multiwall carbon nanotube (PQD-MWCNT) hybrid material. The PQD-MWCNT hybrid material channel is disposed on the substrate between a first electrode and a second electrode and forms a PQD-MWCNT channel. The PDQs comprise a methylammonium lead bromide material. A method of operating the photodetector device as an artificial photonic synapse includes applying a presynaptic signal as stimuli as one or more light pulses on the PQD-MWCNT channel between the first electrode and the second electrode. A current across the PQD-MWCNT channel is measured to represent a postsynaptic signal.

A method for preparing a solar cell, includes: forming a first electrode on a substrate; forming a light absorbing layer on the first electrode; and forming a second electrode on the light absorbing layer, wherein the method further comprises forming an impurity material layer including an impurity element on the light absorbing layer adjacent to the first electrode or the second electrode in any one side or both sides thereof, and forming a doping layer by diffusing the impurity element into a portion of the light absorbing layer.

A phototransistor device to act as an artificial photonic synapse includes a substrate and a graphene source-drain channel patterned on the substrate. A perovskite quantum dot layer is formed on the graphene source-drain channel. The perovskite quantum dot layer is methylammonium lead bromide material. A method of operating the phototransistor device as an artificial photonic synapse includes applying a first fixed voltage to a gate of the phototransistor and a second fixed voltage across the graphene source-drain channel. A presynaptic signal is applied as stimuli across the graphene source-drain channel. The presynaptic signal includes one or more pulses of light or electrical voltage. A current across the graphene source-drain channel is measured to represent a postsynaptic signal.

A method for preparing a solar cell, includes: forming a first electrode on a substrate; forming a light absorbing layer on the first electrode; and forming a second electrode on the light absorbing layer, wherein the method further comprises forming an impurity material layer including an impurity element on the light absorbing layer adjacent to the first electrode or the second electrode in any one side or both sides thereof, and forming a doping layer by diffusing the impurity element into a portion of the light absorbing layer.

Provided is an electronic device that is capable of converting infrared light and ultraviolet light into electrical energy and that exhibits high transparency. The electronic device includes a layer containing a transparent plasmonic material.

The invention provides a beam intensity/positioning monitor substrate comprising a first metal foil in physical contact with a second metal foil. Also provided is a method for determining mass absorption coefficients, the method comprising measuring the absorption of an incident radiation beam by a first metal and a second metal comprising a bi-metal foil as a function of a first energy and a second energy; calculating the relative first metal thickness; using the relative thickness as a target value for the first metal fitting procedure; repeat the above steps on a free standing first metal foil; using the free standing first metal absorption measurements, bulk first metal density and first (bimetal) fit coefficients to determine first metal foil thickness; using free standing first metal to conduct a high resolution scan from just below its absorption edge to 1 keV or higher in energy; and using the free standing first metal absorption measurements below the absorption edge and experimentally determined thickness to compute mass absorption coefficients below its absorption edge.