TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The primary copper-based material comprises copper indium selenide or copper indium gallium selenide. The secondary copper-based material comprises copper indium gallium selenide or copper indium selenide. The primary layer and secondary layer together have thickness of less than 500 nm. The primary copper-based material comprises nanoparticles having negative surface charge or positive surface charge. The secondary copper-based material comprises nanoparticles having positive surface charge or negative positive surface charge. The solar cell further comprises a tertiary layer comprising the primary copper-based material deposited on the secondary layer, a tertiary layer comprising the secondary copper-based material deposited on the tertiary layer, a cadmium-based layer comprising a cadmium-based material, a primary zinc oxide layer comprising a primary zinc oxide material, and a secondary zinc oxide layer comprising a secondary zinc oxide material. The cadmium-based layer has thickness of about 50 nm. The cadmium-based material comprises cadmium sulfide. The primary zinc oxide layer has thickness of between 80 nm and 120 nm. The primary zinc oxide material comprises intrinsic zinc oxide. The secondary zinc oxide layer has thickness of between 100 nm and 140 nm. The secondary zinc oxide material comprises n-type zinc oxide.    TECHNOLOGY FOCUS - POLYMERS - Preferred Layer: The secondary optional deposit layer comprises a deposit layer comprising a material chosen from polyallyl amine hydrochloride, poly-(sodium-4-styrene sulfonate), polyethylene imine, diallyldimethylammonium chloride, and acrylic acid. Preferred Substrate: The substrate comprises a negatively-charged surface. The negatively-charged substrate surface has a deposit of polyallylamine hydrochloride. The substrate is one of flexible and non-flexible substrate chosen from an indium tin oxide coated glass substrate, a copper substrate, a copper-coated substrate, a molybdenum coated substrate, a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) coated substrate, glass, paper, plastic, and textile. The substrate is chosen from a planar substrate, a non-planar substrate, and a nano-planar substrate. The substrate comprises a layer of poly (3,4-ethylenedioxythiophene). The solar cell further comprises a secondary substrate comprising a layer of a zinc material and a layer of indium tin dioxide.