Low-noise organic photodetectors
Although the high performance and low cost of visible light silicon photodetectors suffice for most applications, their small size and rigid nature are not optimal for applications such as wearable sensors. Organic photodetectors can be flexible and large in area but are often noisy. Fuentes-Hernandez et al. found that optimized choices of the semiconductor and electrode materials that improve diode characteristics enable organic photodetectors that can detect low light levels with low noise.
Science, this issue p. 698
Silicon photodiodes are the foundation of light-detection technology; yet their rigid structure and limited area scaling at low cost hamper their use in several emerging applications. A detailed methodology for the characterization of organic photodiodes based on polymeric bulk heterojunctions reveals the influence that charge-collecting electrodes have on the electronic noise at low frequency. The performance of optimized organic photodiodes is found to rival that of low-noise silicon photodiodes in all metrics within the visible spectral range, except response time, which is still video-rate compatible. Solution-processed organic photodiodes offer several design opportunities exemplified in a biometric monitoring application that uses ring-shaped, large-area, flexible, organic photodiodes with silicon-level performance.