A multijunction solar cell includes an InGaAs buffer layer and an InGaAlAs grading interlayer disposed below, and adjacent to, the InGaAs buffer layer. The grading interlayer achieves a transition in lattice constant from one solar subcell to another solar subcell.

A multijunction solar cell includes an InGaAs buffer layer and an InGaAlAs grading interlayer disposed below, and adjacent to, the InGaAs buffer layer. The grading interlayer achieves a transition in lattice constant from one solar subcell to another solar subcell.

A perovskite material including an organic-inorganic perovskite structure of formula (I), A.sub.nMX.sub.3 (I), n being the number of cation A and an integer >4, A being a monovalent cation selected from inorganic cations Ai and/or from organic cations Ao, M being a divalent metal cation or a combination thereof, X being a halide and/or pseudohalide anion or a combination thereof, wherein at least one cation A is selected from organic cations Ao, the inorganic cations Ai are independently selected from Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, or Tl.sup.+ and the organic cations Ao are independently selected from ammonium (NH.sub.4.sup.+), methyl ammonium (MA) (CH.sub.3NH.sub.3.sup.+), ethyl ammonium (CH.sub.3CH.sub.2NH.sub.3).sup.+, formamidinium (FA) (CH(NH.sub.2).sub.2.sup.+), methylformamidinium (CH.sub.3C(NH.sub.2).sub.2.sup.+), guanidium (C((NH).sub.2).sub.3.sup.+), tetramethylammonium ((CH.sub.3).sub.4N.sup.+), dimethylammonium ((CH.sub.3).sub.2NH.sub.2.sup.+) or trimethylammonium ((CH.sub.3).sub.3NH.sup.+).

A perovskite material including an organic-inorganic perovskite structure of formula (I), A.sub.nMX.sub.3 (I), n being the number of cation A and an integer >4, A being a monovalent cation selected from inorganic cations Ai and/or from organic cations Ao, M being a divalent metal cation or a combination thereof, X being a halide and/or pseudohalide anion or a combination thereof, wherein at least one cation A is selected from organic cations Ao, the inorganic cations Ai are independently selected from Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, or Tl.sup.+ and the organic cations Ao are independently selected from ammonium (NH.sub.4.sup.+), methyl ammonium (MA) (CH.sub.3NH.sub.3.sup.+), ethyl ammonium (CH.sub.3CH.sub.2NH.sub.3).sup.+, formamidinium (FA) (CH(NH.sub.2).sub.2.sup.+), methylformamidinium (CH.sub.3C(NH.sub.2).sub.2.sup.+), guanidium (C((NH).sub.2).sub.3.sup.+), tetramethylammonium ((CH.sub.3).sub.4N.sup.+), dimethylammonium ((CH.sub.3).sub.2NH.sub.2.sup.+) or trimethylammonium ((CH.sub.3).sub.3NH.sup.+).

An emission enhancement structure having at least one energy augmentation structure; and an energy converter capable of receiving energy from an energy source, converting the energy and emitting therefrom a light of a different energy than the received energy. The energy converter is disposed in a vicinity of the at least one energy augmentation structure such that the emitted light is emitted with an intensity larger than if the converter were remote from the at least one energy augmentation structure. Also described are various uses for the energy emitters, energy augmentation structures and energy collectors in a wide array of fields.

According to embodiments provided herein, the performance of photovoltaic device can be improved by rapidly heating an absorber layer of a device in open-circuit to a high temperature for a short period of time followed by rapid quenching. The rapid heating may be accomplished by one or more pulses of high intensity electromagnetic energy. The energy may be visible light. The energy may be absorbed primarily in the absorber layer, such that the absorber layer is preferentially heated, promoting chemical reactions of dopant complexes. The dopant chemical reactions disrupt compensating defect complexes that have formed in the device, and regenerate active carriers.

According to embodiments provided herein, the performance of photovoltaic device can be improved by rapidly heating an absorber layer of a device in open-circuit to a high temperature for a short period of time followed by rapid quenching. The rapid heating may be accomplished by one or more pulses of high intensity electromagnetic energy. The energy may be visible light. The energy may be absorbed primarily in the absorber layer, such that the absorber layer is preferentially heated, promoting chemical reactions of dopant complexes. The dopant chemical reactions disrupt compensating defect complexes that have formed in the device, and regenerate active carriers.

A silicon solar cell with high photoelectric conversion efficiency is disclosed. A solar cell for converting light incident from an outside into electricity according to the present invention includes a substrate, a lower electrode, a ferroelectric layer, an auxiliary electrode, a first conductivity-type semiconductor layer, a second conductivity-type semiconductor layer, and an upper electrode. The lower electrode is formed on the substrate. The ferroelectric layer is formed on the substrate and outside the lower electrode. The auxiliary electrode is formed on the ferroelectric layer. The first conductivity-type semiconductor layer is formed on the lower electrode and the auxiliary electrode. The second conductivity-type semiconductor layer is formed on the first conductivity-type semiconductor layer, and is composed of a semiconductor of a second conductivity type opposite to a first conductivity type. The upper electrode is made of transparent conductive material, and is formed on the second conductivity-type semiconductor layer.

A silicon solar cell with high photoelectric conversion efficiency is disclosed. A solar cell for converting light incident from an outside into electricity according to the present invention includes a substrate, a lower electrode, a ferroelectric layer, an auxiliary electrode, a first conductivity-type semiconductor layer, a second conductivity-type semiconductor layer, and an upper electrode. The lower electrode is formed on the substrate. The ferroelectric layer is formed on the substrate and outside the lower electrode. The auxiliary electrode is formed on the ferroelectric layer. The first conductivity-type semiconductor layer is formed on the lower electrode and the auxiliary electrode. The second conductivity-type semiconductor layer is formed on the first conductivity-type semiconductor layer, and is composed of a semiconductor of a second conductivity type opposite to a first conductivity type. The upper electrode is made of transparent conductive material, and is formed on the second conductivity-type semiconductor layer.

In methods and apparatus for improving the power generated, and thus efficiency of solar cells, a double or triple junction tandem solar cell that has one or two photon filters of the invention in between the solar cell layers, respectively. The photon filter is arranged to reflect photons with wavelength shorter than λx and arranged to be transparent to photons of wavelength longer than λx by focussing the lower energy photons out of small area apertures on the other side of the photon filter and arranging the other side of the photon filter to reflect at least some of the photons of wavelength longer than λx. By using the photon filters of the invention in between the solar cell layers, photons can be trapped between filters to solar cell layers at an energy at which the quantum efficiency of the solar cell layer is the best.