Preparation‐Condition Dependence of Hybrid SiO₂‐Coated CdTe Nanocrystals with Intense and Tunable Photoluminescence

Abstract

When aqueously prepared CdTe nanocrystals (NCs) are coated with a SiO2 shell containing Cd ions and a sulfur source, they show a drastic increase in photoluminescence (PL) efficiency with a significant red shift and spectral narrowing after reflux. This is ascribed to the creation of a hybrid structure characterized by the formation of CdS‐like clusters in the vicinity of the NCs in the SiO2 shell. Since these clusters are close to the NCs, their effective size increases to reduce the quantum size effect. The dependences of the PL properties on the preparation conditions are systematically investigated. The PL efficiency increases from 28% to 80% in the best case with a red shift of 80 nm. The PL behaviors differ from those of normal CdTe NCs and include less temperature quenching and longer PL lifetime. The SiO2 coating enables bioconjugation with IgG without deterioration of PL efficiency, making hybrid NCs amenable for bioapplication.

Creation of Functional and Structured Polymer Particles by Self-Organized Precipitation (SORP)

“…Metal nanoparticles (NPs) have unique optical and electronic properties based on their quantum 58 and plasmonic effects. 59 Metal NPs exhibit local plasmonic absorption in the visible light region depending on their size and shape.…”

Enhanced photoluminescence quantum yield of red‐emitting CdTe:Gd3+ QDs for WLEDs applications

“…The emission band of CdTe and CdTe:Gd 3+ QDs consists of two parts: the main excitonic (core) emission and the low‐energy trap‐related (surface) emission, which correspond to the fast and slow component of decay fitting . The average lifetime values of CdTe, CdTe:Gd 3+ (5 mol%), CdTe:Gd 3+ (10 mol%), CdTe:Gd 3+ (20 mol%), and CdTe:Gd 3+ (50 mol%) QDs are 28.37, 28.68, 29.48, 28.19, and 23.21 ns, respectively.…”

Growth Mechanism of Hydrophilic CdTe Nanocrystals with Green to Dark Red Emission

“…The slow component is considered to originate from the surfacerelated emission of the CdTe NCs. 31 The PL lifetime of semiconductor NCs depends strongly on their partical size and surface state. The shortening of the lifetime for smaller NCs is expected because an extra path for depopulating the excited state is created.…”