The purpose of the present invention is to improve power generation efficiency of a photovoltaic element. In a tandem-type photovoltaic element that comprises titanium dioxide and silicon dioxide, silicon dioxide particles that constitute a first photovoltaic layer 24 composed of silicon dioxide are thinly dispersed on a charge exchange layer 23 that is composed of Pt and has a roughness on the surface and on a first conductive film 22 that is composed of FTO and also has a roughness on the surface. Due to this configuration, a photovoltaic element with high power generation efficiency can be obtained.

Provided herein are dyes, dye-sensitized solar cells, and sequential series multijunction dye-sensitized solar cell devices. The dyes include an electron deficient acceptor moiety, a medium electron density -bridge moiety, and an electron rich donor moiety comprising a biaryl, a substituted biaryl, or an R.sup.1, R.sup.2, R.sup.3 substituted phenyl where each of R.sup.1, R.sup.2, and R.sup.3 independently comprises H, aryl, multiaryl, alkyl substituted aryl, alkoxy substituted aryl, alkyl substituted multiaryl, alkoxy substituted multiaryl, OR.sup.4, N(R.sup.5).sub.2, or a combination thereof; each R.sup.4 independently comprises H, alkyl, aryl, alkyl substituted aryl, alkoxy substituted aryl, or a combination thereof; and each R.sup.5 independently comprises aryl, multiaryl, alkyl substituted aryl, alkoxy substituted aryl, alkyl substituted multiaryl, alkoxy substituted multiaryl, or a combination thereof. The solar cells include a glass substrate, a dye-sensitized active layer, and a redox shuttle. The devices include at least two dye-sensitized solar cells connected in series.

Provided herein are dyes, dye-sensitized solar cells, and sequential series multijunction dye-sensitized solar cell devices. The dyes include an electron deficient acceptor moiety, a medium electron density ?-bridge moiety, and an electron rich donor moiety comprising a biaryl, a substituted biaryl, or an R1, R2, R3 substituted phenyl where each of R1, R2, and R3 independently comprises H, aryl, multiaryl, alkyl substituted aryl, alkoxy substituted aryl, alkyl substituted multiaryl, alkoxy substituted multiaryl, OR4, N(R5)2, or a combination thereof; each R4 independently comprises H, alkyl, aryl, alkyl substituted aryl, alkoxy substituted aryl, or a combination thereof; and each R5 independently comprises aryl, multiaryl, alkyl substituted aryl, alkoxy substituted aryl, alkyl substituted multiaryl, alkoxy substituted multiaryl, or a combination thereof. The solar cells include a glass substrate, a dye-sensitized active layer, and a redox shuttle. The devices include at least two dye-sensitized solar cells connected in series.

A three-tandem (3T) perovskite/silicon (PVT)-based tandem solar cell (TSC) includes an antireflection coating (ARC), a first transparent conductive oxide layer (TCO), a hole transport layer (HTL), a perovskite (PVT) layer, a second transparent conductive oxide layer (TCO), an electron transport layer (ETL), a plurality of buried contacts, a p-type Si layer, a p-type wafer-based homo-junction silicon solar cell, a n+ silicon layer, a back contact layer. The solar cell further includes a top sub-cell, a bottom sub-cell and a middle contact-based tandem. The top sub-cell includes the PVT layer. The bottom sub-cell includes the silicon solar cell. The middle contact-based tandem includes the second TCO layer to be used as the middle contact-based tandem, as well as a recombination layer for current collection. Further, a conduction and a valence band edge are employed at a front surface of the ETL.

An aspect of the present disclosure is a perovskite that includes A.sub.(n1nw+w)A.sub.(wnw)A.sub.2B.sub.nX.sub.(3n3zn+3z4e+1)X.sub.(3zn3z)X.sub.4e, where each of A, A, A are monovalent cations, B is a divalent cation, each of X, X, and X are monovalent anions, 0<w1, 0<z1, 0<e1, and 1n100000.

A three-tandem (3T) perovskite/silicon (PVT)-based tandem solar cell (TSC) includes an antireflection coating (ARC), a first transparent conductive oxide layer (TCO), a hole transport layer (HTL), a perovskite (PVT) layer, a second transparent conductive oxide layer (TCO), an electron transport layer (ETL), a plurality of buried contacts, a p-type Si layer, a p-type wafer-based homo-junction silicon solar cell, a n+ silicon layer, a back contact layer. The solar cell further includes a top sub-cell, a bottom sub-cell and a middle contact-based tandem. The top sub-cell includes the PVT layer. The bottom sub-cell includes the silicon solar cell. The middle contact-based tandem includes the second TCO layer to be used as the middle contact-based tandem, as well as a recombination layer for current collection. Further, a conduction and a valence band edge are employed at a front surface of the ETL.

A method for manufacturing a HEMT/HHMT device based on CH.sub.3NH.sub.3PbI.sub.3 material are provided. The method includes: selecting an Al.sub.2O.sub.3 substrate; manufacturing a source electrode and a drain electrode; forming a first electron transport layer on a surface of the source electrode, a surface of the drain electrode, and a surface of the Al.sub.2O.sub.3 substrate not covered by the source electrode and the drain electrode; manufacturing CH.sub.3NH.sub.3PbI.sub.3 material on a surface of the first electron transport layer to form a first light absorbing layer; and forming a gate electrode on a surface of the first light absorbing layer to complete the manufacture of the HEMT device.

Hybrid solar cell plates with integrated bypass diodes and modules thereof are described. In an embodiment, a hybrid solar cell plate includes a step surface including a floor and a step edge extending from the floor and across a thickness of a top subcell. A bypass diode is over the floor and laterally adjacent to the step edge.

Methods of fabricating a graphene film are disclosed. An example method can include providing a substrate, heating the substrate between about 600? C. and about 1100? C. in a chamber, and introducing a carbon source into the chamber at a temperature between about 600? C. and about 1100? C. for about 10 seconds to about 1 minute. The method can further include cooling the substrate to about room temperature to form the graphene film Methods of fabricating pillared graphene nano structures and graphene based devices are also provided.

A process of forming a photoactive layer of a planar perovskite photoactive device comprising: applying at least one layer of a first precursor solution to a substrate to form a first precursor coating on at least one surface of the substrate, the first precursor solution comprising MX.sub.2 and AX dissolved in a first coating solvent, wherein the molar ratio of MX.sub.2:AX=1:n with 0<n<1; and applying a second precursor solution to the first precursor coating to convert the first precursor coating to a perovskite layer AMX.sub.3, the second precursor solution comprising AX dissolved in a second coating solvent, the first precursor solution reacting with the second precursor solution to form a perovskite layer AMX.sub.3 on the substrate, wherein A comprises an ammonium group or other nitrogen containing organic cation, M is selected from Pb, Sn, Ge, Ca, Sr, Cd, Cu, Ni, Mn, Co, Zn, Fe, Mg, Ba, Si, Ti, Bi, or In, X is selected from at least one of F, Cl, Br or I.