A photovoltaic module employing an array of photovoltaic cells disposed between two optically transparent substrates such as to define a closed-loop peripheral area of the module that does not contain a photovoltaic cell. The module is sealed with a peripheral seal along the perimeter; and is devoid of a structural element affixed to an optically transparent substrate and adapted to mount the module to a supporting structure. The two substrates may be bonded together with adhesive material and, optionally, the peripheral seal can include the adhesive material. The module optionally includes diffraction grating element(s) adjoining respectively corresponding PV-cell(s).