This research introduces an advanced multilayer system to maximize solar energy harvesting and thermal control by combining photovoltaic (PV), thermochromic, and phase-change materials (PCMs). The top layer is a semi-transparent PV (STPV) module that transforms some of the direct sunlight into electricity while permitting the remaining portion to pass through for additional energy utilization. Placed underneath, a thermochromic layer changes its state from transparent to reflective, and vice versa, within a 25–30°C temperature interval, maximizing energy absorption and enhancing the efficiency of bifacial PV through the secondary radiation of excess sunlight to the backside of the PV module. Below the threshold temperature, the thermochromic layer is kept in a transparent condition, and light is transmitted, allowing it to enter and be deposited as thermal energy in the supporting PCM layer. This PCM layer absorbs and stores excess heat at times of intense solar exposure and slowly releases it when temperatures reduce, regulating temperature fluctuations. At the bottom, a geopolymer base serves as a thermal reservoir, additionally contributing to heat regulation while offering mechanical stability. With effective sunlight and thermal energy management, this multistep system optimizes solar utilization, increases PV performance, and helps enable sustainable energy solutions for future-generation solar applications.