The rapid advancement of wearable health technology has transformed photoplethysmography (PPG) from a clinical diagnostic tool into a ubiquitous method for continuous physiological monitoring. However, the translation of clinical-grade fidelity into wearable form factors is currently hindered by the material limitations of standard optoelectronics. Conventional silicon-based sensors, while electronically mature, suffer from intrinsic rigidity and broadband optical absorption, necessitating complex geometric structuring and external filtration to mitigate motion artifacts and background noise. This review provides a comprehensive analysis of the materials landscape for next-generation PPG photodetectors, evaluating candidates against three critical design criteria: spectral matching to physiological windows, mechanical compliance with biological tissue, and biocompatibility. By critically comparing the optoelectronic figures of merit, stability trade-offs, and processing requirements of the distinct families, this paper identifies key strategies for bridging the gap between rigid electronics and soft biological systems, paving the way for the mass adoption of unobtrusive, high-fidelity health monitors.
Gwóźdź et al. (Fri,) studied this question.