The invention relates to a solar energy absorber unit for a solar energy device, and methods of producing the same. The unit includes a collector plate having a front surface adapted to absorb solar energy and a rear surface. A rear panel has an inner surface attached to areas of the rear surface of the collector plate via a fluid-tight bond but leaving a fluid-conveying channel between the areas of the rear surface of the plate where the panel is attached. The collector plate and preferably the rear panel are each made of a core layer of an aluminum alloy provided with a cladding layer formed on a side of the core layer that confronts the fluid-conveying channel, the cladding layer being made of aluminum or an aluminum alloy having a total content of alloying elements and impurities, if any, of no more than 0.5 wt. %.