Supercrystals of CdSe Quantum Dots with High Charge Mobility and Efficient Electron Transfer to TiO2

被引：58

作者：

Talgorn, Elise ^{[1
]}

Abellon, Ruben D. ^{[1
]}

Kooyman, Patricia J. ^{[2
]}

Piris, Jorge ^{[1
]}

Savenije, Tom J. ^{[1
]}

Goossens, Albert ^{[1
]}

Houtepen, Arjan J. ^{[1
]}

Siebbeles, Laurens D. A. ^{[1
]}

机构：

[1] Delft Univ Technol, Optoelect Mat Sect, Dept Chem Engn, NL-2628 BL Delft, Netherlands

[2] Delft Univ Technol, Catalysis Engn Sect, Dept Chem Engn, NL-2628 BL Delft, Netherlands

来源：

ACS NANO | 2010年 / 4卷 / 03期

关键词：

quantum dot; annealing; supercrystal; photoconductivity; TiO2; SEMICONDUCTOR NANOCRYSTALS; SOLAR-CELLS; SEPARATION EFFICIENCY; EXCITON DIFFUSION; BINDING-ENERGY; II-VI; SOLIDS; FILMS; GROWTH; PBSE;

D O I：

10.1021/nn901709a

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Thermal annealing of thin films of CdSe/CdS core/shell quantum dots induces superordering of the nanocrystals and a significant reduction of the interparticle spacing. This results in a drastic enhancement of the quantum yield for charge carrier photogeneration and the charge carrier mobility. The mobile electrons have a mobility as high as 0.1 cm(2)/(V . s), which represents an increase of 4 orders of magnitude over non-annealed QD films and exceeds existing literature data on the electron mobility in CdSe quantum dot films. The lifetime of mobile electrons is longer than that of the exciton. A fraction of the mobile electrons gets trapped at levels below the conduction band of the Me nanocrystals. These electrons slowly diffuse over 50-300 nm on longer times up to 20 mu s and undergo transfer to a TiO2 substrate, The yield for electron injection in TiO2 from both mobile and trapped electrons is found to be > 16%.

引用

页码：1723 / 1731

页数：9

共 48 条

[1] Perspectives on the physical chemistry of semiconductor nanocrystals [J].

Alivisatos, AP .

JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (31) :13226-13239

[2]

[Anonymous], 2003, Quantum Theory of Tunneling

[3] Spectroscopic study of electronic states in an ensemble of close-packed CdSe nanocrystals [J].

Artemyev, MV ;

Woggon, U ;

Jaschinski, H ;

Gurinovich, LI ;

Gaponenko, SV .

JOURNAL OF PHYSICAL CHEMISTRY B, 2000, 104 (49) :11617-11621

[4]

Berger L I, 1997, SEMICONDUCTOR MAT

[5] Measurement of the radiative and nonradiative decay rates of single CdSe nanocrystals through a controlled modification of their spontaneous emission [J].

Brokmann, X ;

Coolen, L ;

Dahan, M ;

Hermier, JP .

PHYSICAL REVIEW LETTERS, 2004, 93 (10) :107403-1

[6] Nature of photovoltaic action in dye-sensitized solar cells [J].

Cahen, D ;

Hodes, G ;

Grätzel, M ;

Guillemoles, JF ;

Riess, I .

JOURNAL OF PHYSICAL CHEMISTRY B, 2000, 104 (09) :2053-2059

[7] Electron transport in quantum dot solids: Monte Carlo simulations of the effects of shell filling, Coulomb repulsions, and site disorder [J].

Chandler, R. E. ;

Houtepen, A. J. ;

Nelson, J. ;

Vanmaekelbergh, D. .

PHYSICAL REVIEW B, 2007, 75 (08)

[8] PHOTON-INDUCED MOLECULAR CHARGE SEPARATION STUDIED BY NANOSECOND TIME-RESOLVED MICROWAVE CONDUCTIVITY [J].

DEHAAS, MP ;

WARMAN, JM .

CHEMICAL PHYSICS, 1982, 73 (1-2) :35-53

[9] Physicochemical evaluation of the hot-injection method, a synthesis route for monodisperse nanocrystals [J].

Donegá, CD ;

Liljeroth, P ;

Vanmaekelbergh, D .

SMALL, 2005, 1 (12) :1152-1162

[10] Transport properties of annealed CdSe colloidal nanocrystal solids [J].

Drndic, M ;

Jarosz, MV ;

Morgan, NY ;

Kastner, MA ;

Bawendi, MG .

JOURNAL OF APPLIED PHYSICS, 2002, 92 (12) :7498-7503

← 1 2 3 4 5 →