Hybrid polymer inorganic microcavities with CdSe/CdS nanocrystals

ABSTRACTS
_______________________
ICES
2015
P1.13
Hybrid polymer inorganic microcavities with CdSe/CdS nanocrystals
Giovanni Manfredi1, Roman Krahne2, Francesco di Stasio2, Davide Comoretto1
1
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, via
Dodecaneso 31, 16146 Genova, Italy
2
IIT - Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
corresponding author : [email protected]
Microcavities are devices well known in photonics for their ability to create a localization of the
electromagnetic field inside engineered defects of photonic crystals (PhCs). This localization is
of great attraction even in the world of optoelectronics due to the possibility to modify the
behaviour of photoactive materials contained inside the cavities where the field is confined.
Polymers PhCs and cavities are easy to produce and permits to obtain peculiar features like
flexibility. Moreover, the use of nanoparticles and polymer/inorganic nanocomposites makes it
possible to exploit these devices creating passive matrices that host photoactive materials. In
this work is reported the preparation and optical characterization of an all-polymer 1-D
microcavity composed by a photoactive nanocomposite’s defect layer sandwiched between two
DBRs made of polyvynilcarbazole and cellulose acetate. The nanocomposite is formed by
CdSe/CdS core-shell prolated nanocrystals dispersed in a polystyrene matrix. The nanoparticles
are photoactive absorbing light in the blue portion of the visible spectra while showing a strong
photoluminescence in the red. By using the technique of spin coating a very high quality PhC
composed by 101 different layers has been realized. Characterization techniques show a good
quality of the sample and a marked sharpening of the PL spectra respect to the one of bare NCs
reducing the full width at half maximum of the emission from about 24 nm to roughly 2.4 nm.
The reduction of a factor 10 of the width is accompanied by a spectral redistribution of the
emission dependent upon the direction of propagation of the light. This cavity is a prototype that
reveals the potentiality of these kind of polymer structures as platforms suitable to study the
interaction between light and active materials when the electromagnetic field is strongly
modified. Such systems may be exploited for many uses such as lasing or sensing.
123