Executive Summary : | This proposal explores the concept of electric double layer (EDL) induced transient photocurrent generation at polymer/ionic liquid interfaces, aiming to develop a non-invasive wearable electrocardiogram monitor. Currently, photoplethysmography (PPG) technology is used for optical heart rate monitoring, but its accuracy is questionable, especially at heart rates around 155-160 beats per minute. The PPG signal consists of a large DC component and a week pulsatile AC component, which requires filtering, amplifying, and converting before reliable analysis. The proposed new class of photodetectors responds to a pulsed signal and produces AC output without any DC component, making them suitable for direct and highly accurate heart rate monitoring. The flexible and ultrathin nature of these devices supports extreme wearability and conformal integration on human skin, smartphones, or smart-watches. Effective polymers like PCE-10, PTB7, P3HT, PCBM, and Y6 will be used for fabrication of state-of-the-art devices. Different techniques will be employed for detailed characterization, including Uv-Vis absorption studies, Ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and electrochemistry. Active layer films will be processed using spin-coating, spray-coat, or thermal evaporation. Performance parameters such as responsivity, external quantum efficiency, action spectrum, and linear dynamic range will be investigated using time- and frequency-dependent transient photocurrent measurements under different excitation conditions. By combining these studies, a deep understanding of the photophysical properties and structure property relationship of the new class of devices will be achieved, enabling the development of a high-precision non-invasive wearable electrocardiogram monitor. |