Institut des
NanoSciences de Paris

Nanostructures and optics

Study of single nanocrystals

Colloidal nanocrystals are crystalline spheres of a few nanometers, sometimes protected by a shell in order to improve their optical properties. They are very bright and stable emitters and their emission wavelength can be chosen over the whole visible range through the parameters of chemical synthesis (fig. 1a), and their optical properties compare to those of an « artifical atom ».

We collaborate with the group of Benoît Dubertret at the ESPCI (Paris) which studies the synthesis of high quality nanocrystals emitting in the red-near infrared and the optimization of the nanocrystals shell in order to suppress their blinking. We also work with the group of Pham Thu Nga at the IMS (Hanoi). We perform ensemble measurements (emission and absorption spectra, decay curves, quantum yield, low temperature measurements) (fig. 1b) as well as studies on single nanocrystals with a confocal microscope (blinking, single-photon emission, coherence and spectral diffusion (collaboration J.-P. Hermier, GEMaC)...) (fig. 1c).

Fig. 1 : Fluorescence of nanocrystals of CdTeSe synthesized at the ESPCI (left sample) et de CdSe/ZnS synthétisés à l’IMS (3 samples on the right, corresponding to 3 different nanocrystals sizes), illuminated by a UV lamp. (b) Emisison spectra of ensemble of nanocrystals from the IMS at various temperatures. (c) Intensity fluctuations (blinking) of a single nanocrystal from IMS with and without ZnS shell.


Collaborations :

- Benoît Dubertret at LPEM (ESPCI, Paris)

- Pham Thu Nga at l’IMS (VAST, Hanoi)

- Jean-Pierre Hermier, GEMaC


Communications :

- Louis Biadala, Hugo Frederich, Laurent Coolen, Stéphanie Buil, Xavier Quélin, Clémentine Javaux, Michel Nasilowski, Benoît Dubertret and Jean-Pierre Hermier, Photon-correlation Fourier spectroscopy of the trion fluorescence in thick-shell CdSe/CdS nanocrystals, Phys. Rev. B 91, 085416 (2015),

- Hai Yen Nguyen, Willy Daney de Marcillac, Clotilde Lethiec, Ngoc Hong Phan, Catherine Schwob, Agnès Maître, Quang Liem Nguyen, Van Vu Le, Paul Bénalloul, Laurent Coolen and Pham Thu Nga, Synthesis and optical properties of core/shell ternary/ternary CdZnSe/ZnSeS quantum dots, Opt. Mater. 36, 1534 (2014),

- J. Laverdant, W. Daney de Marcillac, C. Barthou, C. Schwob, L. Coolen, P. Benalloul, P. T. Nga et A. Maître, Experimental determination of fluorescence quantum yield of semiconductor nanocrystals, Materials 4, 1182 (2011).

- P. T. Nga, V. D. Chinh, V.T. H. Hanh, N. X. Nghia, P.T. Dzung, C. Barthou, P. Benalloul, J. Laverdant, et A. Maître, Optical properties of normal and “giant” multishell CdSe quantum dots for potential application in material science, Int. J. Nanotechnol., Vol. 8, 347 (2011), Special Issue on Nanotechnology in Vietnam.

- Nga, P.T., Chinh, V.D., Linh, P.T., Cuong, K.C., Hanh, V.T.H. and Nghia, N.X., Barthou, C. Maître, A., The temperature effect on photoluminescence properties of CdSe/ZnS quantum dots, Adv. in Nat. Sci., Vol. 10, 167-174 (2009).

- C. Barthou, C. Vion, L. Coolen, P. Benalloul, Pham Thu Nga, Vu Duc Chinh, Pham Thuy Linh, Vu Thi Bich, Pham Thu Nga, A. Maître, Luminescence Properties of II/VI Semiconductor Colloidal Nanocrystals at Collective and Single Scale, Asean Workshop On Advanced Materials Science And Nanotechnology (Nha Tran, Vietnam, 15-21 septembre 2008), IOP Publishing, Journal of Physics : Conference Series 187 (2009) 012018

- Nguyen Xuan Nghia, Pham Thu Nga, Vu Duc Chinh, Le Ba Hai, Phan Tien Dung, Do Thuy Chi, C. Barthou, P. Bénalloul, C. Vion et A. Maître, Synthesis and optical properties of core-shell semiconductor quantum dots in opal photonic crystals, Conference on Nanoscience and Technology (Pékin, Chine, juin 2007)

- Pham Thu Nga, Nguyen Van Chuc, Vu Duc Chinh, Nguyen Xuan Nghia, Phan Tien Dung, Dao Nguyen, Thuan, Pham Thai Cuong, Chu Viet Ha, Vu Hong Hanh, Vu Thi Kim Lien, Thai Nguyen, C. Barthou, P. Bénalloul, M. Romanelli et A. Maître, Synthesis and optical properties of colloidal core-shell semiconductor nanocrystals quantum dots for sensory application, 5th IEE Conference on Sensors (Daegu, Corée, octobre 2006)