Abstract: A tray for testing and storage of photovoltaic e.g. solar cells, is described, enabling processing or testing of such cells to be conducted while supported on the tray. The tray comprises a base having a peripheral rim extending upwardly around the upper surface of the base, and serving to at least partially retain one or more of the cells within a pre-defined position on the upper surface. One or more indexing elements are provided on the upper surface of the tray to co-operate with the peripheral rim to define a number of pre-defined cell positions on the upper surface of the tray, for selectively retaining any of a plurality of different sized cells. A vacuum chamber is provided to retain the solar cell in its pre-defined position on the tray. Apertures are provided in the base of the tray and extend to the pre-defined cell positions to permit probes to extend therethrough and into contact with the solar cell.