Highly Luminescent Hybrid SiO2-Coated CdTe Quantum Dots Retained Initial Photoluminescence Efficiency in Sol-Gel SiO2 Film.
A highly luminescent silica film was fabricated using tetraethyl orthosilicate (TEOS) and 3-aminopropyltrimethoxysilane (APS) through a controlled sol-gel reaction. The pre-hydrolysis of TEOS and APS which resulted in the mixture of TEOS and APS in a molecular level is a key for the formation of homogenous films. The aminopropyl groups in APS play an important role for obtaining homogeneous film with high photoluminescence (PL). Red-emitting hybrid SiO2-coated CdTe nano-crystals (NCs) were fabricated by a two-step synthesis including a thin SiO2 coating via a sol-gel process and a subsequent refluxing using green-emitting CdTe NCs. The hybrid SiO2-coated CdTe NCs were embedded in a functional SiO2 film via a two-step process including adding the NCs in SiO2 sol with a high viscosity and almost without ethanol and a subsequent spinning coating. The hybrid SiO2-coated CdTe NCs retained their initial PL efficiency (54%) in the film. Being encapsulated with the hybrid NCs in the film, no change on the absorption and PL spectra of red-emitting CdTe NCs (632 nm) was observed. This indicates the hybrid NCs is stable enough during preparation. This phenomenon is ascribed to the controlled sol-gel process and a hybrid SiO2 shell on CdTe NCs. Because these films exhibited high PL efficiency and stability, they will be utilizable for potential applications in many fields.
Hongsheng
H
Sun
Yugui
Y
Xing
Qinan
Q
Wu
Ping
P
Yang
D000327:Adsorption; D019187:Cadmium Compounds / Q000737:chemistry*; D004735:Energy Transfer; D008163:Luminescent Measurements / Q000379:methods*; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D044367:Phase Transition; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*
D019187:Cadmium Compounds; D012822:Silicon Dioxide; D013691:Tellurium; C028337:cadmium telluride