Clusterization-Triggered Room-Temperature Phosphorescence of Konjac Glucomannan Foams with High Mechanical Strength

Room-temperature phosphorescence (RTP) materials with high mechanical strength are attractive and important but rarely reported. In this study, konjac glucomannan (KGM), a polysaccharide derived from natural taro, was observed to emit long-lived RTP via clusterization-triggered emission (CTE). The CTE behavior of KGM was fully investigated in solution and in the solid state. The distinct concentration-enhanced emission observed for KGM aqueous solutions, combined with its low toxicity and high biocompatibility, renders KGM highly promising for bioimaging. KGM foams were observed to emit RTP via the fixation of multiple hydrogen bonds to clusters of oxygen-containing groups. The phosphorescence lifetime of KGM foam could reach 351.2 ms, and the lightweight KGM foam could withstand compressive stress of 5.73 MPa. KGM foams exhibit typical excitation wavelength (λex)-dependent color-tunable RTP, with afterglows changing from blue-green to grass-green as λex is increased from 310 to 365 nm. The results indicate that KGM is suitable for the development of eco-friendly RTP materials with high mechanical strength.