Preparation Of Fluorescent Silicon Quantum Dots And Its Fluorescence Property

Semiconductor quantum dots were a new kind of nanomaterials with unique optical property since they were discovered last century.But the potential contamination,high cost,cell toxicity and bad biocompatibility with the use of high metal element have greatly impeded their real application.Silicon quantum dots were promising candidate in light of the excellent biocompatibility,abundant and low cost of silicon element.In this article,we got water soluble silicon quantum dots by one-pot microwave assisted method and thoroughly investigated their fluorescence response to pH of solution and heavy metal ions,research the quenching mechanism and prepare silicon quantum dots/PU composite.The main work of the article was as follow:1.Water soluble silicon quantum dots with high quantum yield exceed 85%were successfully prepared with sodium citrate and N-?-(aminoethyl)-y-aminopropyl trimethoxyl silane by microwave method.The silicon quantum dots were nearly monodispersed with good crystalline.2.The influence of solution surroundings to silicon quantum dots was thoroughly investigated.In basic solution with pH>6,the fluorescence remained stable,but in acid solution with pH from 2 to 6,the fluorescence of silicon quantum dots decreased as the pH decreased with a little red shift.While the fluorescence of silicon quantum dots was strongly quenched in the presence of Cr(VI),there was good linearship between the intensity of quenching and the amount of Cr(VI)with a low detection limit of 20[iM.3.The procedure of synthesis of silicon quantum dots and PU composite was researched.Silicon quantum dots were used as multifunctional chain extender and embedded uniformly in polymer matrix initially.The mechanical property of composite was investigated.