GaAs Concentrator Solar Cells Research Articles

Photovoltaic Characteristics of Low-density Concentration GaAs Solar Cells with/without Anti-reflective Coating

We have studied photovoltaic characteristics of single-junction GaAs solar cells with/without an <TEX>$MgF_2/ZnS$</TEX> anti-reflective coating (ARC) illuminated by low-density concentration (<10 suns). By the ARC deposition, the short-circuit current density (<TEX>$J_{SC}$</TEX>) and the fill factor (FF) are increased by <TEX>$5mA/cm^2$</TEX> and 5% at a standard illumination (1 sun), respectively, and the resulted conversion efficiency is enhanced by 45%. In contrast with the cell with no ARC showing a rapid degradation with increasing concentration power, the efficiency of ARC-deposited cell remains almost constant as (<TEX>$17.7{\pm}0.3$</TEX>)% regardless of the concentration. It informs that ARC treatment is very effective in GaAs concentrator solar cells.

Effects of temperature and series resistance on GaAs concentrator solar cell

Concentrators use reflection or refraction of light, or a combination of both, but concentration of light leads to a crucial heating of the cell, which involves degradation of its performance. However, solar cells especially conceived for concentration can support very intense illuminations as far as an active cooling is assured. In this work, a GaAs solar cell with Al x Ga 1-x As window layer, operating under low injection conditions, has been studied with temperature and solar concentration. The temperature corresponding to each concentration was calculated, and then used in the calculation of photovoltaic parameters. The study was carried out under free mode conditions (without heat sink) and then under forced conditions (with a cooling system) in order to demonstrate the importance of cooling in the concentrator solar cells. The effect of series resistance on solar cell characteristics has also been studied. The simulation was carried out using SCAPS-1D simulator. The results were compared with those obtained theoretically; a good agreement was found between the two models.

A comparative study of BSF layers for GaAs-based single-junction or multijunction concentrator solar cells

An effective back surface field is a key structural element for a high-efficiency GaAs concentrator solar cell, either in a multijunction or in a single-junction device. In this paper, several BSF materials are analysed, namely: (1) p++GaAs(Zn), (2) p+Ga0.5In0.5P(Zn) and (3) p++Al0.2Ga0.8As(C). The results of the comparison demonstrate that the best option is C-doped Al0.2Ga0.8As, which exhibits a low series resistance and behaves as an excellent minority carrier mirror; p++GaAs(Zn) shows reduced minority carrier mirror properties resulting from Zn diffusion and p+Ga0.5In0.5P(Zn) is shown to produce important series resistance problems because of an unfavourable heterojunction with GaAs.

Comparison of 1D and 3D analysis of the front contact influence on GaAs concentrator solar cell performance

An extensive analysis of the front contact influence on concentrator GaAs solar cell performance has been carried out. The fill factor, open circuit voltage and efficiency have been calculated by varying the front contact specific resistance and the metal sheet resistance for 500X, 1000X and 2000X. An optimum front grid design has also been developed. The simulations have been carried out using a 3D model based on distributed circuit units, and by a classic lumped model, showing the need to use distributed models to achieve an accurate concentrator solar cell modeling as well as a precise front grid design.

Efficiency of silicon and GaAs concentrator solar cells operated inside integrating cavity receivers

Abstract The theory for the general case of solar cells operating inside integrating cavity receivers is established. This is applied to the particular case of different configurations of silicon and GaAs cells. The results of the analysis show that a composite system of silicon and GaAs cells manufactured using relatively simple technology could reach an efficiency of 34%. The optimal configuration is that in which the GaAs cells are placed in the directly illuminated area of the receiver and the silicon cells are placed in the indirectly illuminated area of the receiver.

GaAs Concentrator Solar Cells Using Aluminum-Cored Printed Circuit Bases

An effective cooling method is essential for GaAs concentrator solar cells operated under highly concentrated sunlight, because the conversion efficiencies of the cells decrease at high temperature. We fabricated aluminum-cored printed circuit bases which consist of an aluminum core, anodic oxide layer of aluminum, polymer layer such as polyimide, and metal layer. In this paper we report that this aluminum-cored printed circuit base is effective and that on this base a higher conversion efficiency can be obtained than on a conventional alumina ceramic base. Cell conversion efficiencies of 23.9%, 23.7%, and 22.6% were obtained at 96 suns, 186 suns, and 327 suns, respectively, from the GaAs concentrator solar cell mounted on the aluminum-cored printed circuit base.

Flash technique for GaAs concentrator solar cell measurement

A flash-lamp testing technique for the measurement of GaAs concentrator solar cells is described. This method allows a simple and rapid evaluation of efficiency, series resistance and fill factor of the cell at high concentrations. A comparison with outdoor measurements is also reported.