Synthesis of Silver Nanoplates with a Narrow LSPR Band for Chemical Sensing Through a Plasmon-Mediated Process Using Photochemical Seeds

Abstract The plasmon-mediated process is one of the most common and well-studied methods to synthesize silver nanoplates (AgNPts). In a typical plasmon-mediated process, silver seeds are generated by chemical reduction using NaBH4 (abbreviated as CR seeds) before the plasmon-mediated process. However, a broad localized surface plasmon resonance (LSPR) band of AgNPts (usually broader than 150 nm) synthesized using the typical plasmon-mediated process would possibly limit their further applications. In this study, silver seeds are generated using a photochemical reduction method (abbreviated as PCR seeds). These PCR seeds then convert to AgNPts with irradiation by green LEDs or by a sodium lamp through the plasmon-mediated process. Furthermore, a very narrow LSPR bandwidth (approximately 67 nm) can be obtained when these AgNPts are further irradiated with red LEDs. Due to high refractive index sensitivity and sharp LSPR bandwidth, the as-prepared AgNPts have a high figure of merit (FOM) and can be used for spectroscopic chemical sensing applications. The silver seeds generated by this photochemical method can provide another choice for the plasmon-mediated process to synthesize AgNPts with high optical quality.