TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Component: The first sealant cap can be made of glass including aluminosilicate glass, borosilicate glass, dichroic glass, germanium/semiconductor glass, glass ceramic, silicate/fused silica glass, soda lime glass, quartz glass, chalcogenide/sulfide glass, fluoride glass, PYREX(RTM: borosilicate glass), a glass-based phenolic, cereated glass, or flint glass.    TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Component: The assembly further comprises Lambertian or diffuse albedo surface positioned to reflect sunlight into photovoltaic modules. The albedo surface has an albedo of more than 80%. The photovoltaic module further comprises a water resistant layer and an antireflective coating disposed on all or a portion of the transparent casing; first and second sealant caps that respectively hermetically seal two ends of the transparent casing. All or a portion of the elongated substrate is a rigid tube or a rigid solid rod. A solar cell in the one or more solar cells has cylindrical shape. The elongated substrate or the transparent casing is nonplanar and has a circular cross-section, an ovoid cross-section, a triangular cross-section, a pentangular cross-section, a hexagonal cross-section, a cross-section having at least one arcuate portion, or a cross-section having curved portion(s). Preferred Properties: The first refractive index is greater than or equal to 1.5. The second refractive index is approximately 1.6. The third refractive index is 1.2-1.9. The portion of the elongated substrate that is rigid has a Young's modulus of greater than or equal to 20, preferably greater than or equal to 70 GPa. The longitudinal dimension of the elongated substrate is greater than or equal to 50 cm. The width dimension of the elongated substrate is greater than or equal to 1, preferably greater than or equal to 5 cm.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The semiconductor junction of a first solar cell in the one or more solar cells comprises a first layer comprising a first inorganic semiconductor; and a second layer comprising a second inorganic semiconductor. The first layer comprises copper-indium-gallium-diselenide.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The first sealant cap is made of metal or metal alloy.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The filler material comprises ethylene vinyl acetate, silicone, silicone gel, silicone-based oil, epoxy, polydimethyl siloxane, room temperature vulcanizable silicone rubber, polyvinyl butyral, thermoplastic polyurethane, polycarbonate, acrylic, fluoropolymer, or urethane. The filler material is formed from silicone oil mixed with a dielectric gel. The dielectric gel is a mixture of first and second silicone elastomers. The silicone oil is polydimethylsiloxane polymer liquid of formula (CH3)3SiO(SiO(CH3)2)nSi(CH3)3.n=range of integers such that the liquid has an average bulk viscosity of 40-60, preferably 50-100000 cSt.Preferred Properties: The filler material has a thermal coefficient of expansion of greater than 500x 10-6/ degrees C; and a viscosity of less than 1x 106 cP. The photovoltaic module has a water transmission rate of less than or equal to 10-4, preferably less than or equal to 10-7 g/m2-day. Preferred Composition: The polydimethylsiloxane polymer liquid is present at 30-90 wt.%. The first silicone elastomer is present at 2-20 wt.%. The second silicone elastomer is present at 2-20 wt.%. The first silicone elastomer comprises (wt.%) dimethylvinyl-terminated dimethyl siloxane ( greater than or equal to 60) and silicate (3-7). The second silicone elastomer comprises (wt.%) dimethylvinyl-terminated dimethyl siloxane ( greater than or equal to 60), hydrogen-terminated dimethyl siloxane (10-30), and trimethylated silica (3-7).