Abstract

Colloidal semiconductor nanocrystals, with intense and sharp-line emission between red andnear-infrared spectral regions, are of great interest for optoelectronic and bio-imagingapplications. The growth of an inorganic passivation layer on nanocrystal surfaces is a commonstrategy to improve their chemical and optical stability and their photoluminescence quantumyield. In particular, cation exchange is a suitable approach for shell growth at the expense of thenanocrystal core size. Here, the cation exchange process is used to promote the formation of aCdS passivation layer on the surface of very small PbS nanocrystals (2.3 nm in diameter), blueshifting their optical spectra and yielding luminescent and stable nanostructures emitting in therange of 700-850 nm. Structural, morphological and compositional investigation confirms thenanocrystal size contraction after the cation-exchange process, while the PbS rock-salt crystallinephase is retained. Absorption and photoluminescence spectroscopy demonstrate the growth of apassivation layer with a decrease of the PbS core size, as inferred by the blue-shift of theexcitonic peaks. The surface passivation strongly increases the photoluminescence intensity andthe excited state lifetime. In addition, the nanocrystals reveal increased stability against oxidationover time. Thanks to their absorption and emission spectral range and the slow recombinationdynamics, such highly luminescent nano-objects can find interesting applications in sensitizedphotovoltaic cells and light-emitting devices.

Autore Pugliese

• Giannini Cinzia , Sibillano Teresa , Striccoli Marinella , Comparelli Roberto

Tutti gli autori

• E. Binetti ; M. Striccoli ; T. Sibillano ; C. Giannini ; R. Brescia ; A. Falqui ; R. Comparelli ; M. Corricelli ; R. Tommasi ; A. Agostiano ; M. L. Curri

Titolo volume/Rivista

Science and technology of advanced materials

Anno di pubblicazione

2015

ISSN

1468-6996

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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