Existing CO2 sensors face limitations in sensitivity, power efficiency, and reliability under varying environmental conditions. The demand for accurate, portable, and low-maintenance solutions spans industries such as healthcare, agriculture, and environmental monitoring. This Solid-State CO2 Sensor leverages advanced composite materials to deliver real-time, precise carbon dioxide detection across a range of 100–10,000 ppm. Operating at room temperature, the sensor is compact, low-power, and capable of functioning in both humid and dry environments, making it suitable for mobile devices, wearables, and critical safety systems.