A multijunction solar cell with a graded interlayer disposed between two adjacent solar subcells, the graded interlayer being compositionally graded to lattice match a first solar subcell on one side, and an adjacent second solar subcell on the other side, the graded interlayer being composed of at least four step layers, a particular step layer having a lattice constant in the range of 0.2 to 1.2% greater than the lattice constant of the adjacent layer on which it is grown, and the subsequent steps layers disposed directly on the particular step layer having a lattice constant in the range of 0.1 to 0.6% greater than the particular layer on which it is grown, and wherein the thickness of the particular step layer is at least twice the thickness of each of the other subsequent step layers.

A multijunction solar cell with a graded interlayer disposed between two adjacent solar subcells, the graded interlayer being compositionally graded to lattice match a first solar subcell on one side, and an adjacent second solar subcell on the other side, the graded interlayer being composed of at least four step layers, a particular step layer having a lattice constant in the range of 0.2 to 1.2% greater than the lattice constant of the adjacent layer on which it is grown, and the subsequent steps layers disposed directly on the particular step layer having a lattice constant in the range of 0.1 to 0.6% greater than the particular layer on which it is grown, and wherein the thickness of the particular step layer is at least twice the thickness of each of the other subsequent step layers.

An apparatus and method for producing a perpetual energy harvester which harvests ambient near ultraviolet to infrared radiation and provides continual power regardless of the environment. The device seeks to harvest the largely overlooked blackbody radiation through use of a semiconductor thermal harvester, providing a continuous source of power. Additionally, increased power output is provided through a solar harvester. The solar and thermal harvesters are physically connected but electrically isolated.

A multijunction solar cell including an upper first solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a second solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the first and second subcells and having a graded lattice constant that matches the first subcell on a first side and the second subcell on the second side, and having a fifth band gap that is greater than the second band gap of the first solar subcell.

A multijunction solar cell including an upper first solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a second solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the first and second subcells and having a graded lattice constant that matches the first subcell on a first side and the second subcell on the second side, and having a fifth band gap that is greater than the second band gap of the first solar subcell.

A photosensitive device and method includes a top cell having an N-type layer, a P-type layer and a top intrinsic layer therebetween. A bottom cell includes an N-type layer, a P-type layer and a bottom intrinsic layer therebetween. The bottom intrinsic layer includes a Cu—Zn—Sn containing chalcogenide.

A photosensitive device and method includes a top cell having an N-type layer, a P-type layer and a top intrinsic layer therebetween. A bottom cell includes an N-type layer, a P-type layer and a bottom intrinsic layer therebetween. The bottom intrinsic layer includes a Cu—Zn—Sn containing chalcogenide.

Dilute nitride subcells with graded doping are disclosed. Dilute nitride subcells having graded doping display improved efficiency, short circuit current density, and open circuit voltage.

A composition of matter, in particular a photovoltaic cell, comprising: at least one core semiconductor nanowire on a graphitic substrate, said at least one core nanowire having been grown epitaxially on said substrate wherein said nanowire comprises at least one group III-V compound or at least one group II-VI compound or at least one group IV element; a semiconductor shell surrounding said core nanowire, said shell comprising at least one group III-V compound or at least one group II-VI compound or at least one group IV element such that said core nanowire and said shell form a n-type semiconductor and a p-type semiconductor respectively or vice versa; and an outer conducting coating surrounding said shell which forms an electrode contact.

A multijunction solar cell including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other including first top solar subcell, second (and possibly third) lattice matched middle solar subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein an opening is provided from the bottom side of the semiconductor substrate to one or more of the solar subcells so as to allow a discrete electrical connector to be made extending in free space and to electrically connect contact pads on one or more of the solar subcells.