Low Cost, Low Bandgap Thermophotovoltaic Cells

Using new low bandgap GaSb photovoltaic cells, JX Crystals has recently demonstrated functional thermophotovoltaic prototype generators. While it is generally believed that the cost of materials makes non-silicon photovoltaic cells prohibitively expensive unless one can develop thin film cells, this thesis is wrong for thermophotovoltaic cells. Specifically for the GaSb cell, the Ga and Sb material contribution to the electric power cost is only 7.3 cents per Watt. The real cell costs in high volume production are associated with process costs, and the GaSb cell process can be made inexpensive by copying the silicon solar cell process. This has already been done by using diffusions for junction formation and converted silicon Czochalski pullers for crystal growth. JX Crystals is proposing to undertake several additional process improvements imitating the simple silicon solar cell process, at every step from crystal growth to wafer sawing to wafer handling. By imitating the silicon cell process, JX Crystals believes that Ga Sb thermophotovoltaic cells can be made in high volume production at a cost of under $1 per Watt.