The effect of plasmonic films containing gold nanoparticles of different shape (nanospheres and nanorods) on the photostability of InP/ZnSe/ZnSeS/ZnS and CdSe/ZnCdS/ZnS quantum dots with core/shell structure has been determined. Gold nanospheres increase the photostability of InP/ZnSe/ZnSeS/ZnS quantum dots when excited by blue LED radiation when reducing the average lifetime of the excited state of quantum dots and, accordingly, when reducing the probability of Auger processes. An increase in the average lifetime of the excited state of CdSe/ZnCdS/ZnS quantum dots in complexes with gold nanorods leads to a decrease in the photostability upon excitation at 449 and 532 nm.

The effect of gold and silver plasmonic films on the photoluminescence and photostability of InP/ZnSe/ZnSeS/ZnS nanocrystals (quantum dots) is reported. Colloidal gold films promote the photostability enhancement of InP/ZnSe/ZnSeS/ZnS quantum dots (more durable emission properties in the presence of metal nanostructures) through reducing exciton lifetime. In contrast, silver decreases the photostability of InP/ZnSe/ZnSeS/ZnS quantum dots without changing the photoluminescence intensity and kinetics. By adjusting the excitation wavelength closer to the extinction band of gold nanoparticles a 1.8-fold enhancement of luminescence intensity has been obtained using a polyelectrolyte spacer between the metal and InP/ZnSe/ZnSeS/ZnS nanoparticles. Thus, plasmonics offers essential practical improvement of light emitters in terms of their durable luminescent properties upon prolonged optical excitation without losses in luminescence efficiency or even along with increased efficiency.

Photoluminescent properties of CdSe/ZnS nanocrystals (quantum dots, QDs) in complexes with elongated gold nanoparticles was found to be dependent on the effective refractive index of the medium. It has been experimentally shown that changes in the refractive index make possible to increase the photoluminescence intensity by several times.

Anisotropic polymer films containing aligned Au nanorods and semiconductor nanoparticles of various shape were fabricated. The photoluminescence of semiconductor nanoparticles in these films is partially polarized. The value of the photoluminescence polarization degree of quantum dots embedded in an anisotropic PVA-film after 4.5-fold stretching P = 0.27 has been obtained.

Photoluminescence of CdSe colloidal nanocrystals of different topologies in an external electric field has been studied. It has been found that quenching of photoluminescence, which takes place in quantum dots, is proportional to the square of the field, and in elongated nanocrystals quenching of photoluminescence is proportional to the square root. A physical model of the mechanism of quenching based on tunneling of free charges through potential barrier nanocrystal/matrix has been proposed.

A comparative analysis of photoluminescence quenching of CdSe colloidal quantum dots, nanorods, and nanoplatelets under external electric field has been carry out. Experimentally it has been demonstrated that for the quantum dots the PL quenching is more efficient than in the same nanorods and nanoplatelets. The functional dependence of PL intensity quenching vs. magnitude of electric field has been established and is in good accordance with the probability of charge tunneling under a triangular potential barrier.

Physics, Chemistry and Applications of Nanostructures, pp. 62-64 (2015) No AccessPHOTOLUMINESCENCE OF SEMICONDUCTOR QUANTUM-SIZED CdSe NANOPLATELETS IN EXTERNAL ELECTRIC FIELDL. I. GURINOVICH, E. V. SHABUNYA-KLYACHKOVSKAYA, S. V. GAPONENKO and A. V. PRUDNIKAUL. I. GURINOVICHB. I. Stepanov Institute of Physics NASB, Nezavisimosti Ave. 68, 220072 Minsk, Belarus, E. V. SHABUNYA-KLYACHKOVSKAYAB. I. Stepanov Institute of Physics NASB, Nezavisimosti Ave. 68, 220072 Minsk, Belarus, S. V. GAPONENKOB. I. Stepanov Institute of Physics NASB, Nezavisimosti Ave. 68, 220072 Minsk, Belarus and A. V. PRUDNIKAUResearch Institute for Physical Chemical Problems, Belarusian State University Leningradskaya 14, 220030 Minsk, Belarushttps://doi.org/10.1142/9789814696524_0015Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Colloidal quantum-sized CdSe nanoplatelets were synthesized. Photoluminescence (PL) spectra of nanoplatelets placed in the external electric field and excited with various radiation sources were measured. The functional dependence of PL intensity vs magnitude of the electric field is in good accordance with the E−1/2 law. This dependence is similar to that for CdSe nanorods contrary to the E−2 law for CdSe quantum dots. FiguresReferencesRelatedDetailsCited By 1The effect of an external electric field on photoluminescence of CdSe colloidal nanoparticles of different topologiesA. O. Muravitskaya, L. I. Gurinovich, A. V. Prudnikau, M. V. Artemyev and S. V. Gaponenko24 February 2017 | Optics and Spectroscopy, Vol. 122, No. 1 Physics, Chemistry and Applications of NanostructuresMetrics History PDF download

This work presents a comprehensive study of electroabsorption in CdSe colloidal quantum dots, nanorods, and nanoplatelets. We experimentally demonstrate that the exposure of the nanoplatelets to a dc electric field leads to strong broadening of their lowest-energy heavy-hole absorption band and drastically reduces the absorption efficiency within the band. These are results of the quantum-confined Stark and Franz–Keldysh effects. The field-induced change in the nanoplatelets' absorption is found to be more than 10 times the change in the absorption by the quantum dots. We also demonstrate that the electroabsorption by the nanorods is weaker than that by the quantum dots and nanoplatelets and reveal an unusual dependence of the differential absorption changes on the nanoplatelet thickness: the thicker the nanoplatelet, the smaller the change.

We studied electro-optical effects in 2D quantum confined CdSe nanoplatelets synthesized by colloidal chemistry. They were incorporated into transparent polymeric film sandwiched between two ITO electrodes to which the electric potential has been applied. The electro-optical response in the nanoplatelets has a Stark-like character similar to observed elsewhere for CdSe quantum dots and nanorods. However, the magnitude of the Stark effect in the platelets is of the order of magnitude higher than that in quantum dots or nanorods of an equivalent diameter. The electro-optical response from the nanoplatelets is partially polarized.

The dependence of photoinduced processes in cadmium selenide nanocrystals in an external electric field on the energy of the exciting photons is established. A relationship between the photoinduced buildup of photoluminescence and its quenching in an external electric field in quantum sized cadmium selenide nanocrystals is demonstrated. The mechanisms for the quenching of the photoluminescence and for the influence of the exciting photon energy on the photoinduced processes are discussed.

The effect of external electric fields on the photoluminescence of quantum-sized nanocrystals of cadmium selenide excited by photons of various energies is studied. Photoluminescence quenching by external electric fields is found to be different for nanoparticles with different shapes (quantum dots and nanorods) and does not depend on the exciting photon energy. The relationship between the strength of the external electric field and the degree of quenching is determined empirically for both types of nanoparticles. A possible mechanism for the effect of an external electric field on the excitation and quenching of photoluminescence in quantumsized nanoparticles is discussed.

We have demonstrated a difference in the nature of the effect of a strong external electric field (>105 V/cm) on the photoluminescence of cadmium selenide nanoparticles of different shapes. We have determined a correlation between the magnitude of the external electric field and the average photoluminescence decay time for two types of nanoparticles: "quantum dots" and nanorods. We discuss the mechanism for the effect of an electric field on the photoluminescence of both types of nanoparticles.

We studied electric field effects on optical properties of CdSe/ZnS nanorods integrated in thin films sandwiched between transparent electrodes. It was demonstrated that P-polarized component of the photoluminescence of CdSe/ZnS nanorods is quenched stronger by external electric field than the S-polarized component. Quantum dots are more sensitive to external electric field than the nanorods. A mechanism of external electric field influence on the luminescence spectrum of semiconductor nanorods is discussed.

It is found that the absorption and luminescence spectra of CdSe nanocrystals and nanorods depend on the external electric field. It is shown that the external electric field quenches the P-polarized photoluminescence of CdSe nanorods to a degree higher than the degree of field-induced quenching of the S-polarized photoluminescence. It is established that the nanocrystals are more sensitive to the external electric field than the nanorods. The effect of the external electric field on the luminescence properties of the semiconductor nanorods is discussed.

For biological applications of quantum dots it is important to develop the technology for water soluble highly luminescent cadmium selenide nanocrystals. Obviously, the as-synthesized hydrophobic nanocrystals can not be utilized as fluorescent markers in immunoanalysis since such material must be water compatible [1-2]. The problem of synthesis and photostability of high fluorescent aqueous solutions for the visible based on soluble semiconductor nanocrystals is a topical question.

We have developed a method for solubilization of hydrophobic CdSe/ZnS nanocrystals of the core/shell type, obtained by high-temperature synthesis in coordinating organic solvents. The method is based on chemical modification of the surface of the nanocrystals with hydrophilic organic mercapto compounds. We have observed that long-chain mercaptoundecanoic acid molecules effectively protect the surface of CdSe/ZnS nanocrystals in water, increasing (compared with short-chain molecules) the photostability of the nanocrystals.