Sensors Unlimited has announced that high-resolution, shortwave infrared (SWIR) area and linescan cameras are being used to improve the manufacturing yield of photovoltaic (PV) cells.
SWIR technology is well suited to monitor the quality of solar thin films, concentrated PV, and crystalline cells, to maximise efficiency of the solar-cell manufacturing process through final assembly of the completed modules.
The Ingaas-based SWIR cameras, which operate between 0.9 to 1.7 microns, are ideal for inspecting silicon boules and wafers due to the material's transparency beyond 1.2 microns.
The Goodrich cameras reveal voids in silicon boules, bricks, and ingots before they are sliced into wafers to produce mono- and multi-crystalline solar cells.
They can also detect hidden cracks by mapping stress in raw wafers, finished cells, and thin films made for solar electricity generating panels.
SWIR cameras can also spot saw marks on the opposite side of a silicon wafer and/or defects inside the material.
In addition, by applying forward bias to cells to generate electroluminescence, the SWIR cameras are used to gauge cell efficiency and uniformity.
This aids improvement of cell manufacturing processes, and aids matching cells with similar efficiencies for assembly into modules.
The latter step prevents the loss of energy from the stronger cells which would be lost in heating the inefficient cells.
