Precise Photoplethysmography Sensor Based on High‐Efficiency Perovskite Light‐Emitting Diodes

Photoplethysmography (PPG) sensors play a vital role in human health monitoring, particularly for blood oxygen saturation and heart rate detection. However, the measurement accuracy of PPG sensors remains constrained by light source chromatic purity, hindering their broader application. Here, we employ high‐color‐purity perovskite materials with an optimally designed device to construct a PPG sensor, successfully enabling real‐time monitoring of blood oxygen saturation and heart rate. Through device performance optimization, we discovered that high‐purity green light generates more effective signals, thereby enhancing Peripheral Oxygen Saturation ( SpO 2 ) measurement accuracy. Consequently, our PPG sensor demonstrates repeatability and high accuracy comparable to commercial blood oxygen and heart rate monitors. This work not only demonstrates that high color purity enhances the testing accuracy of SpO 2 , thereby paving new avenues for the fabrication of high‐precision PPG sensors, but more significantly, it broadens the application scope of perovskite LEDs in the field of health monitoring.