TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The silver component consists of substantially pure silver. The silver component comprises at least 2 wt.% of elemental silver. The silver component comprises a silver alloy comprising at least 2 wt.% of elemental silver. The silver component is conductive pastes, connecting wires, conductive coatings or reflector films. The solar cells comprise wafer-based solar cells consisting of monocrystalline silicon or multi-crystalline silicon based solar cells. The solar cells comprise thin film solar cells and the thin film solar cells comprise one or more materials consisting of amorphous silicon, microcrystalline silicon, cadmium telluride, copper indium selenide, copper indium/gallium diselenide, light absorbing dyes or organic semiconductors.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The pre-lamination assembly further comprises one or more additional layers consisting of: a second poly(vinyl butyral) sheet being in contact with the solar cell assembly; a protective outer layer that is in contact with the poly(vinyl butyral) sheet; a second protective outer layer in contact with the second poly(vinyl butyral) sheet; and a substrate or a superstrate i.e. in contact with the solar cell assembly and with the poly(vinyl butyral) sheet.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The unsaturated heterocyclic compound is 1H-benzotriazole or non-2H-substituted benzotriazole derivative of formula (I) or imidazole or their derivative of formula (II). The unsaturated heterocyclic compound is 1H-benzotriazole, 5-methyl-1H-benzotriazole, imidazole, 2-methyl imidazole or 1H-1,2,3-triazole. The poly(vinyl butyral) encapsulant comprises 0.2-0.5 wt.% of the unsaturated heterocyclic compound(s). The poly(vinyl butyral) encapsulant is in the form of a poly(vinyl butyral) sheet, and where the poly(vinyl butyral) sheet has a yellowness index of 60 or less when measured in accordance with ASTM E313-05 after 1000 hours under a bias of 1000 V and at 85 degrees C and 85% relative humidity. The poly(vinyl butyral) encapsulant further comprises one or more additives consisting of 0.01-1 wt.% of at least one UV absorber, 0.01-1 wt.% of at least one thermal stabilizer, 0.01-1 wt.% of at least one hindered amine, and 0.01-1 wt.% of at least one chelating agent, based on the total weight of the poly(vinyl butyral). The UV absorber(s) are 2H-substituted benzotriazole derivatives, the thermal stabilizer(s) comprise octylphenol or butylated hydroxytoluene, the hindered amine(s) are 2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethylpiperadinol, 2-(dimethylamino)pyridine, 4-(dimethylamino)pyridine, N-butyl piperidine, N,N-diethyl cyclohexylamine or hindered amine light stabilizers, or the chelating agent(s) are EDTA, ethylenediamine monoacetic acid, ethylenediamine diacetic acid, ethylenediamine triacetic acid, ethylene diamine, tris(2-aminoethyl)amine or diethylene triaminepentacetic acid.R = H or a substituent, preferably alkyl groups, singly or multiply unsaturated hydrocarbon groups, amino groups, OH, alkoxy groups or halo (further optionally substituted with halo or unbranched 1-4C alkyl).