Directions for further development of GaAs/CuInSe2 thin film tandem cells

Multijunction thin film solar cells utilizing GaAs and CuInSe2 as semiconductor absorbers are rapidly developing, becoming a viable technology for space power systems with an unparalleled combination of high efficiency, low mass, and high radiation tolerance. The prospect for evolutionary improvement of this type of cell towards efficiency of approximately equals 30 percent and specific power greater than 1 kW/kg while retaining the attribute of high radiation tolerance are good. Limitations of the present configuration and possible avenues for circumventing these problems are presented

Development of tandem cells consisting of GaAs single crystal and CuInSe2/CdZnS polycrystalline thin films

The tandem cells consisting of GaAs single crystal and CuInSe2 polycrystalline thin films are being developed under the joint program of the Boeing Co. and Kopin Corp. to meet the increasing power needs for future spacecraft. The updated status of this program is presented along with experimental results such as cell performance, and radiation resistance. Other cell characteristics including the specific power of and the interconnect options for this tandem cell approach are also discussed

Revani diffusion model in Cu(In,Ga)Se2

The commercial attractiveness of Cu(In,Ga) (S,Se)(2) (CIGS) photovoltaics is still curtailed by the R&D gap that separates it from silicon. Overcoming the gap requires the pursuit of strategic approaches, leaving plenty of room for R&D at both industrial and lab scale. Yet, its technological progress hinges on our understanding of the diffusion phenomena that occur during and after the absorber growth, particularly in combination with alkali metal doping. This contribution introduces a simplified model of atomic diffusion in CIGS based on insights drawn from recent and older (but crucial) literature. The concept of anisotropy-induced fluctuations emerges. We hypothesize that grain-dependent inhomogeneities arise in CIGS devices because of crystallographic dependent alkali metal diffusivities. Numerical simulations reveal that inhomogeneous doping density and CdS buffer layer thickness may impair the device performance by up to more than 1% absolute efficiency

Absorption enhancing and passivating non-planar thin-film device architectures for copper indium gallium selenide photovoltaics

The sub-micrometer absorber regime is currently being explored to reduce materials usage and deposition time while simultaneously increasing device voltages due to increased generated carrier concentration. In order to realize these benefits, the absorption of photons must be maintained or even increased while avoiding detrimental recombination. Reported here are optoelectronic simulations that highlight photon and generated carrier management opportunities for improvement of thin film Cu(InxGa1-x)Se2 (CIGSe) device performance. Structures that could be created via either self-assembly, patterning by nanoimprint lithography, or a combination of both are predicted to significantly increase short circuit current density and open circuit voltage simultaneously

Absorption enhancing and passivating non-planar thin-film device architectures for copper indium gallium selenide photovoltaics

The sub-micrometer absorber regime is currently being explored to reduce materials usage and deposition time while simultaneously increasing device voltages due to increased generated carrier concentration. In order to realize these benefits, the absorption of photons must be maintained or even increased while avoiding detrimental recombination. Reported here are optoelectronic simulations that highlight photon and generated carrier management opportunities for improvement of thin film Cu(InxGa1-x)Se2 (CIGSe) device performance. Structures that could be created via either self-assembly, patterning by nanoimprint lithography, or a combination of both are predicted to significantly increase short circuit current density and open circuit voltage simultaneously

Absorption enhancing and passivating non-planar thin-film device architectures for copper indium gallium selenide photovoltaics

The sub-micrometer absorber regime is currently being explored to reduce materials usage and deposition time while simultaneously increasing device voltages due to increased generated carrier concentration. In order to realize these benefits, the absorption of photons must be maintained or even increased while avoiding detrimental recombination. Reported here are optoelectronic simulations that highlight photon and generated carrier management opportunities for improvement of thin film Cu(InxGa1-x)Se2 (CIGSe) device performance. Structures that could be created via either self-assembly, patterning by nanoimprint lithography, or a combination of both are predicted to significantly increase short circuit current density and open circuit voltage simultaneously