2007
Photovoltaic cells based on GaSb and Ge for solar and thermophotovoltaic applications,
Journal of Solar Energy Engineering, Vol. 129, N 3, August 2007, pp.291-297
V.P.Khvostikov, O.A.Khvostikova, P.Y.Gazaryan, S.V.Sorokina, N.S.Potapovich, A.V.Malevskaya, N.A.Kaluzhniy, M.Z.Shvarts, V.M.Andreev
In the present work, high efficient photovoltaic (PV) cells based on gallium antimonide have been developed with the use of the liquid phase epitaxy (LPE) and diffusion from the gas phase techniques. There are intended for conversion of the infrared (IR) part of the solar spectrum in mechanically stacked tandems and for conversion of the thermal radiation of emitters heated by the sunlight. On the ground of investigation of the LPE temperature regimes and the tellurium doping during the process, GaSb PV cells have been fabricated with the efficiency of 6 % behind the single-junction GaAs top cell at the concentration of 300 suns and of 5.6 % at 300 suns behind the dual-junction GaInP/GaAs structure with substrate thickness 100 μm (here and later the efficiency of PV cells is calculated for AM1.5D Low aerosol Optical Depth (Low AOD) spectrum 1000 W/m2). The rated efficiency of conversion of solar powered tungsten emitter radiation by PV cells based on gallium antimonide in thermophotovoltaic (TPV) module appeared to be about 19 %.
Photovoltaic cells based on germanium with a wide-gap GaAs window grown by LPE or MOCVD and a p-n junction formed by means of the zinc diffusion from the gas phase have been fabricated. Ge based PV cells without a wide-gap GaAs window have the efficiency of up to 8.6 % at the concentration of 150 suns. The efficiency of Ge based cells with a wide-gap GaAs window is 10.9 % at the concentration of 150 suns. Ge cells with the efficiency of 4.3 % behind a single-junction GaAs top cell at the concentration of 400 suns have been also obtained. The maximum rated conversion efficiency of Ge PV cells appeared to be about 12 % in the case of conversion of the tungsten emitter thermal radiation. These efficiency values for Ge based cells are among the highest ones. In0.53Ga0.47As/InP thermophotovoltaic cells with uniform doping of the base,
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
L.B. Karlina, V.V. Evstropov, V.S. Kalinovsky, M.M. Kulagina, N.H. Timoshina, A.S. Vlasov, E.P. Rakova, V.M. Andreev
Characteristics of inverted In0.53Ga0.47As/InP thermophotovoltaic (TPV) cells with the uniformly doped base grown on electrically active n-type InP substrates are presented. Thermophotovoltaic cells based on lattice matched InP/In0.53Ga0.47As heterostructures were fabricated with the use of LPE and Zn,P diffusion from a local source in an open system in the hydrogen atmosphere. The TPV cells (spectral range of 1000-1800nm) with different base and emitter thicknesses have been investigated. These TPV cells had doping concentrations up to 2-4x1019cm-3 for the base layers and up to (2-5)x1017cm-3 for the emitter layers. From obtained dark I-V characteristics and photovoltaic characteristics of the InGaAs/InP TPV cell p-n junctions, the dark resistanceless I-V characteristic has been determined. Note, that the diffusion component value determining the potential efficiency of the InGaAs/InP photocell corresponds to the present-day quality of the best InGaAs TPV cells fabricated by the MOCVD technique. Electrical measurements using a flash tester reveal the open circuit voltage of 0.44-0.49V, the fill factor of 75-76% at short circuit current density of 1x10A/cm2. The calculated efficiencies for a TPV cell with uniformly doped base are 16-17% for the tungsten emitter temperature of 1800-2000K. Thus, the developed technique of Zn diffusion from a local source is a highly efficient low cost method for manufacture of TPV cells and can be successfully used in industrial production. Thermophotovoltaic cells and modules based on GaSb
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
V.P.Khvostikov, S.V.Sorokina, N.S.Potapovich, A.S.Vlasov, A.V.Malevskaya, M.Z.Shvarts, V.M.Andreev
The GaSb based structures were developed and fabricated by the Zn-diffusion technique for thermophotovoltaic applications using wafers prepared from ingots grown by the Czochralski technique. Outdoor measurements of an array of three GaSb cells connected in parallel in a cylindrical TPV system were carried out under illumination from tungsten emitters of different lengths. The maximum cylindrical system array photocurrent of 3.5 A has been obtained at the tungsten emitter temperature of 1400oC. The effect of the shape and depth of the p-n junction on basic characteristics of the GaSb TPV cells has been studied. An optimum Zn diffusion profile and a depth of the p-n junction have been found, which allowed to obtain the maximum efficiency of GaSb cells at high generated photocurrent density of up to 5 A/cm2. To choose ceramics material, as a heatsink for GaSb cells, the behavior of these cells: under illumination from a heated SiC emitter was studied. The use of different ceramic heatsinks gives an increase in temperature not higher than 100oC with respect to the cell mounted on the copper heatsink. Concentrator GaInP/GaAs tandem solar cells with in-situ monitoring of the MOCVD growth.
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
V.M. Andreev, N.A.Kalyuzhnyy, V.M.Lantratov, S.A.Mintairov, M.Z.Shvarts, N.K.Timoshina
The dual-junction GaInP/GaAs solar cell monolithic structures have been grown by the MOCVD technique. For both terrestrial and space solar spectra, current matching of the top and bottom cells has been achieved by changing the top GaInP cell thickness. GaInP/GaAs SCs obtained have demonstrated the conversion efficiency of 30.03% ( AM1.5D, 40suns) and 26.5% (AM0, 30suns). During the experiments, in-situ monitoring of the grown structures by methods of the normalized reflectance and reflection anisotropy spectroscopy (RAS) was performed. These measurements allowed determining the growth rate, doping levels and compositions of ternary solid solutions for the dual-junction SC monolithic structure layers. Study of the influence of the linear electro-optic effect on the RAS spectra in the temperature range of 500-750oC has been carried out. It has been found that, for the GaAs layers doped with Si, it is possible to determine the impurity concentration in the range of 1.3x1017-3x1018ρμ-3, and for the GaAs layers doped with Zn in the rage of 2x1017-1.6x1019 cm-3. RAS spectra of n- and p-type GaInP layers at 725oC have been recorded. Full scale solar TPV generator
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
V.M. Andreev, A.S. Vlasov, V.P. Khvostikov, O.A. Khvostikova, P.Y. Gazaryan, N.S. Potapovich
Solar thermophotovoltaic system development is reported. Module design with performance analysis of its parts is presented. Advanced design of the PV part of the system allowed to minimize the Ohmic losses and achieve fill factor values of 0.63-0.7 for a full module, which is close to the values of single GaSb cells. A cost-effective concentrator with a Fresnel lens ensuring 3200x with 86% collection efficiency was used. 5.5 W of the total power output ensuring 3.5% TPV module efficiency was registered under the Sun (EDir=850 W/m2). Possible system alignments are discussed and the effect of each modification is analyzed. Current flow mechanisms and potential efficiency of single- and multi-junction solar cells
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
V.S.Kalinovsky, V.M.Andreev, V.V.Evstropov, N.A.Kaluzhniy, V.P.Khvostikov, V.M.Lantratov, S.A.Mintairov
The resistanceless (not accounting for the p-n structure series resistance RS) current-voltage characteristic defines the limiting efficiency of single- and multi-junction solar cells (SC). In the present work, such characteristics have been obtained for single-junction (GaAs, GaSb) SCs and for dual-junction (GaInP/GaAs) monolithic SCs. For this, the following characteristics independent of RS were used: open circuit voltage-illumination intensity, electroluminescence intensity-forward current. An equation correlating in an explicit form the p-n junction potential efficiency and the photogenerated current has been deduced. This equation may be applied for a multi-junction SC, if one uses the concept of a resulting p-n junction simulating p-n junctions connected in series. The diode coefficients of the resulting p-n junction are equal to the sum of the diode coefficients of p-n junctions connected in series, and the preexponential factors are their geometrical mean (at the equality of the diode coefficients of the p-n junctions connected). The deduced equation was used for calculation of the potential efficiency of the SCs investigated. It follows from the investigations carried out that, in calculating the SC efficiency at concentrations of up to 100 suns, the recombination mechanism of current flow should be taken into account. Weakening of the chromatic aberration negative effect on the performance of concentrator milti-junction solar cells
Presented at the 22ndEuropean Photovoltaic Solar Energy Conference, Milan, Italy, 3-7 September 2007
V.M.Andreev, V.A.Grilikhes, A.A.Soluyanov, N.H.Timoshina, E.V.Vlasova, M.Z.Shvarts
In the paper presented is a procedure for determining the optimal position of a triple-junction solar cell (TJ SC) on the Fresnel lens (FL) optical axis, at which the negative effect of the chromatic aberration (CA) on the performance of TJ SC is weakened and the «FL-SC» system efficiency reaches maximum. The procedure based on the analysis of distributions of densities of the photocurrents generated by p-n junctions obtained from rated distributions of illumination fluxes in the focal plane with allowing for the spectral response of separate junctions. The estimations are verified outdoors, and a good fit with natural experiment results was obtained. It was established that in the real system the efficiency maximum is achieved at the FF maximum, which allows using the dependence of the latter on the «FL-SC» distance as a probe for funding the optimum SC position. It is also shown that, in optimizing the profile and parameters of Fresnel lenses for the systems based on TJ SC with the purpose to weaken the chromatic aberration negative effect, the maximum of the concentration in the focal plane could be used as a criterion. Solar thermophotovoltaics,
«Concentrator Photovoltaics», Eds.: A.Luque, V.Andreev, Springer Series in Optical Sciences, vol.130, 2007,
V.M.Andreev, V.P.Khvostikov, A.S.Vlasov
III-V heterostructures in photovoltaics,
«Concentrator Photovoltaics», Eds.: A.Luque, V.Andreev, Springer Series in Optical Sciences, vol.130, 2007,
Zh.I.Alferov, V.M.Andreev, V.D.Rumyantsev
Solar concentrator modules with fresnel lens panels,
Proc. of the Fourth Int. Conf. on Solar Concentrators for the Generation of Electricity or Hydrogen, El Escorial, Spain, 2007,
V.D.Rumyantsev, A.E.Chalov, N.Yu.Davidyuk, E.A.Ionova, N.A.Sadchikov, V.M.Andreev
The new approach to design of Fresnel lens sunlight concentrator,
Proc. of the Fourth Int. Conf. on Solar Concentrators for the Generation of Electricity or Hydrogen, El Escorial, Spain, 2007,
V.A. Grilikhes, V.M. Andreev, A.A. Soluyanov, E.V. Vlasova, M.Z. Shvarts
Indoor characterization of multijunction concentrator cells under flash illumination with variable spectrum,
Proc. of the Fourth Int. Conf. on Solar Concentrators for the Generation of Electricity or Hydrogen, El Escorial, Spain, 2007,
V.D.Rumyantsev, V.M.Andreev, V.R.Larionov, D.A. Malevskiy, M.Z.Shvarts