High‐Performing Acid‐Free PEDOT:PSS‐Based Organic Photodiodes for Cardiovascular Disease Diagnosis

Abstract Photodetectors made from low‐toxicity organic materials are considered a promising alternative to conventional inorganic photodetectors. However, the performance of current organic photodetectors (OPD) needs to be further enhanced. This study aims to introduce acid‐free poly(3,4‐ethylenedioxythiophene)‐(polystyrene sulfonate) (PEDOT‐(PSS)) films in order to improve the performance of OPDs in practical applications. Utilization of heterocyclic 1,3‐diazole (HDZ) in PEDOT‐(PSS) improves the polymerization degree, carrier mobility, and other physicochemical properties. These enhanced properties also improve the comprehensive performance of OPD. In this flow, the enhanced noise suppression is also confirmed by elucidating the device's performance limitations. Consequently, the presented OPD‐based photoplethysmography sensor has the ability to diagnose blood circulation status and cardiovascular diseases. This accomplishment marks the first in single pixel‐based organic photodiode research.