Size-dependent room-temperature luminescence decay from PbS quantum dots

We study size dependence of kinetic and spectral properties of near-infrared luminescence from PbS quantum dots in colloidal solution. Luminescence lifetimes are found to lie between 250 ns for the largest quantum dots and 2:5 μs for the smallest ones, while the Stoke's shift is found to increase from 4-5 to 300 meV. These results are explained by the presence of the long-living in-gap state, with the size-dependent energy. Analytical modeling shows that the relaxation from this state is dominant in small quantum dots and negligible in large ones. Biexponential luminescence decay with the size-dependent recombination rates is predicted for quantum dots of all sizes.

[1]  P. Guyot-Sionnest,et al.  Interband and Intraband Optical Studies of PbSe Colloidal Quantum Dots , 2002 .

[2]  J. Lewis,et al.  Unconventional gap state of trapped exciton in lead sulfide quantum dots , 2010, Nanotechnology.

[3]  Antonio Luque,et al.  Enhancement of up-conversion efficiency by combining rare earth-doped phosphors with PbS quantum dots , 2010 .

[4]  G. Konstantatos,et al.  Colloidal Quantum Dot Photodetectors , 2013 .

[5]  Frank W. Wise,et al.  Optical Properties of Colloidal PbSe Nanocrystals , 2002 .

[6]  Halina Rubinsztein-Dunlop,et al.  Highly efficient luminescence from a hybrid state found in strongly quantum confined PbS nanocrystals , 2006, Nanotechnology.

[7]  Xiaomei Jiang,et al.  Confinement-dependent below-gap state in PbS quantum dot films probed by continuous-wave photoinduced absorption. , 2008, The journal of physical chemistry. B.

[8]  K. Blum.  Density Matrix Theory and Applications , 1981 .

[9]  H. Rubinsztein-Dunlop,et al.  A PbS quantum-cube: conducting polymer composite for photovoltaic applications , 2004 .

[10]  Andrey V. Veniaminov,et al.  Calibration of the spectral sensitivity of instruments for the near infrared region , 2011 .

[11]  Ludovico Cademartiri,et al.  Size-dependent extinction coefficients of PbS quantum dots. , 2006, Journal of the American Chemical Society.

[12]  N. Peyghambarian,et al.  PbS quantum-dot-doped glasses for ultrashort-pulse generation , 2000 .

[13]  Byung-Ryool Hyun,et al.  Near-infrared fluorescence imaging with water-soluble lead salt quantum dots. , 2007, The journal of physical chemistry. B.

[14]  C. A. Parker.  Photoluminescence of Solutions: With Applications to Photochemistry and Analytical Chemistry , 1968 .

[15]  I. Moreels,et al.  Size-dependent optical properties of colloidal PbS quantum dots. , 2009, ACS nano.

[16]  A. Nozik.  Quantum dot solar cells , 2002 .

[17]  Byung-Ryool Hyun,et al.  Role of solvent dielectric properties on charge transfer from PbS nanocrystals to molecules. , 2010, Nano letters.

[18]  Liyuan Han,et al.  Colloidal quantum dot solar cells , 2011 .

[19]  Frank W. Wise,et al.  Resonant Energy Transfer in PbS Quantum Dots , 2007 .

[20]  A. Rogach,et al.  Infrared-emitting colloidal nanocrystals: synthesis, assembly, spectroscopy, and applications. , 2007, Small.

[21]  F. Wise,et al.  Electronic structure and optical properties of PbS and PbSe quantum dots , 1997 .

[22]  Illan J. Kramer,et al.  RETRACTED: Advances in colloidal quantum dot solar cells: The depleted-heterojunction device , 2011 .

[23]  P. Kamat,et al.  4.09 – Quantum Dot Solar Cells , 2011 .

[24]  Andrey V. Veniaminov,et al.  A complex for the fluorescence analysis of macro- and microsamples in the near-infrared , 2011 .

[26]  Alexander V. Baranov,et al.  Measurement of the luminescence decay times of PbS quantum dots in the near-IR spectral range , 2012 .

[27]  Botao Wu,et al.  Broadband near-infrared luminescence and tunable optical amplification around 1.55 μm and 1.33 μm of PbS quantum dots in glasses , 2011 .

[28]  J. Warner,et al.  Time-resolved photoluminescence spectroscopy of ligand-capped PbS nanocrystals , 2005, Nanotechnology.