Photodegradation of SiO2-coated CdS nanoparticles within silica gels.
A comparative study of the photodegradation of CdS nanoparticles coated with silica shells dispersed in water and embedded in two silica gels with different pore size is presented. Although encapsulation of the quantum dots in a silica shell previously was proven to provide a basically permanent protection against light-induced surface oxidation (photodegradation), this protection is not always maintained when the coated particles are incorporated within different silica gels. Degradation of the CdS occurs when the coated particles are incorporated within silica gels with an open structure, which suggests that the shells somehow crack due to tension in the gel structure. This behavior is analyzed by absorption and luminescence spectroscopies, electron microscopy, and nitrogen sorption.
Correa-Duarte
M A
MA
Departamento de Química Física, Universidade de Vigo, 36200 Vigo, Spain.
Kobayashi
Y
Y
Caruso
R A
RA
Liz-Marzán
L M
LM
D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D004868:Equipment Failure; D019544:Equipment Failure Analysis / Q000379:methods; D008027:Light; D049449:Luminescence; D008422:Materials Testing / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods; D016062:Porosity; D012666:Semiconductors; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry / Q000528:radiation effects*; D013440:Sulfides / Q000737:chemistry* / Q000528:radiation effects*
D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D058428:Silica Gel; D012822:Silicon Dioxide