PHOTORESPONSE OF COLLOIDAL QUANTUM DOTS - CONDUCTING SNO2 MATRIX COMPOSITE

Photoconductivity of composite based on CdSe quantum dots - conducting nanocrystalline SnO2 matrix have been investigated. Colloidal CdSe nanocrystals were synthesized with the use of oleic acid as a tabilizer. CdSe nanocrystals mean size was found to be 3.1 nm with a low size distribution (< 8%). According to the results. of X-ray diffraction tin dioxide matrix consist of nanocrystallites with an average size of about 25 nm. Considerable (as large as 100 times) photoresponse under the illumination with wavelength correlated to lower quantum transition 1 S(h)3/2 -> 1 S-e (550 nm for mentioned QDs size) were observed. Kinetic dependences were characterized by quite a fast response (typically similar to 100 ms) and delayed (typically similar to minutes) dark relaxation.