White-Light Photosensors Based on Ag Nanoparticle-Reduced Graphene Oxide Hybrid Materials

• Main Authors: Wei-Chen Tu, Xiang-Sheng Liu, Shih-Lun Chen, Ming-Yi Lin, Wu-Yih Uen, Yu-Cheng Chen, Yu-Chiang Chao
• Format: Article
• Language: English
• Published: MDPI AG 2018-12-01
• Series: Micromachines
• Subjects: photosensor; reduced graphene oxide; Ag nanoparticles; solution process; finite-difference time-domain
• Online Access: https://www.mdpi.com/2072-666X/9/12/655

The unique and outstanding electrical and optical properties of graphene make it a potential material to be used in the construction of high-performance photosensors. However, the fabrication process of a graphene photosensor is usually complicated and the size of the device also is restricted to micrometer scale. In this work, we report large-area photosensors based on reduced graphene oxide (rGO) implemented with Ag nanoparticles (AgNPs) via a simple and cost-effective method. To further optimize the performance of photosensors, the absorbance and distribution of the electrical field intensity of graphene with AgNPs was simulated using the finite-difference time-domain (FDTD) method through use of the surface plasmon resonance effect. Based on the simulated results, we constructed photosensors using rGO with 60⁻80 nm AgNPs and analyzed the characteristics at room temperature under white-light illumination for outdoor environment applications. The on/off ratio of the photosensor with AgNPs was improved from 1.166 to 9.699 at the bias voltage of −1.5 V, which was compared as a sample without AgNPs. The proposed photosensor affords a new strategy to construct cost-effective and large-area graphene films which raises opportunities in the field of next-generation optoelectronic devices operated in an outdoor environment.