The United States of America as Represented by the United States

Jx Crystals Inc.

Edward J Brown

Paul F Baldasaro

Lewis M Fraas

John E Samaras

Greg W Charache

Randolph J Dziendziel

David M Depoy

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Lapped substrate for enhanced backsurface reflectivity in a

A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.IF ; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5.lambda..sub.IF.

Segregated tandem filter for enhanced conversion efficiency in a

In the present invention, a thermophotovoltaic electric power generator is described. It contains low bandgap photovoltaic cells sensitive in the infrared out to at least 1.7 microns and a broadband infrared emitter with a shortpass IR filter located between the cells and the emitter to recycle the nonuseful IR back to the emitter. Several specific IR filter designs as well as filter/cell and filter/emitter combinations are described all of which improve the overall generator conversion efficiency.

Spectral control for thermophotovoltaic generators

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Clifton Park, NY, United States of America

Edward J Brown