Excitation dependence of steady-state photoluminescence in CdSe nanocrystal films

被引:16
作者
Babentsov, V [1 ]
Riegler, J [1 ]
Schneider, J [1 ]
Fiederle, M [1 ]
Nann, T [1 ]
机构
[1] Univ Freiburg, Freiburger Mat Forschungszentrum, D-79104 Freiburg, Germany
关键词
D O I
10.1021/jp052229c
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The excitonic and deep-level photoluminescence (PL) in CdSe nanocrystal (NC) films (wurtzite type) was studied under continuous-wave excitation as a function of excitation power, temperature, and time of photoaging. It was shown that the intensity-power dependencies are identical for excitonic and deep-level emissions in a wide temperature range. At low temperatures (80- 100 K), both emissions were saturated at the laser power used, which generates more than one exciton per nanocrystal. A transition point from the linear to the saturated region was dependent on the temperature, size, and quality of the NCs. A clear inverse dependency between the intensities of excitonic and deep-level emissions was revealed at 80 K over the entire sample area. At room-temperature, the quantum yield dropped significantly and a higher laser power was needed to reach PL saturation. An increase in temperature led to worsening of the reverse dependence between excitonic and deep-level emissions, and at room-temperature, they became uncorrelated. These results can be explained by Auger recombination and also by an increase of nonradiative recombination in the surface states with increasing temperature.
引用
收藏
页码:15349 / 15354
页数:6
相关论文
共 34 条
[1]   Multiexcitons confined within a subexcitonic volume: Spectroscopic and dynamical signatures of neutral and charged biexcitons in ultrasmall semiconductor nanocrystals [J].
Achermann, M ;
Hollingsworth, JA ;
Klimov, VI .
PHYSICAL REVIEW B, 2003, 68 (24)
[2]   Semiconductor clusters, nanocrystals, and quantum dots [J].
Alivisatos, AP .
SCIENCE, 1996, 271 (5251) :933-937
[3]   Evidence for a thermal contribution to emission intermittency in single CdSe/CdS core/shell nanocrystals [J].
Banin, U ;
Bruchez, M ;
Alivisatos, AP ;
Ha, T ;
Weiss, S ;
Chemla, DS .
JOURNAL OF CHEMICAL PHYSICS, 1999, 110 (02) :1195-1201
[4]   Statistical aging and nonergodicity in the fluorescence of single nanocrystals [J].
Brokmann, X ;
Hermier, JP ;
Messin, G ;
Desbiolles, P ;
Bouchaud, JP ;
Dahan, M .
PHYSICAL REVIEW LETTERS, 2003, 90 (12) :4-120601
[5]   Semiconductor nanocrystals as fluorescent biological labels [J].
Bruchez, M ;
Moronne, M ;
Gin, P ;
Weiss, S ;
Alivisatos, AP .
SCIENCE, 1998, 281 (5385) :2013-2016
[6]   The pump power dependence of the femtosecond relaxation of CdSe nanoparticles observed in the spectral range from visible to infrared [J].
Burda, C ;
Link, S ;
Mohamed, MB ;
El-Sayed, M .
JOURNAL OF CHEMICAL PHYSICS, 2002, 116 (09) :3828-3833
[7]   Transient photoluminescence and simultaneous amplified spontaneous emission from multiexciton states in CdSe quantum dots [J].
Caruge, JM ;
Chan, YT ;
Sundar, V ;
Eisler, HJ ;
Bawendi, MG .
PHYSICAL REVIEW B, 2004, 70 (08) :085316-1
[8]   Quantum dot bioconjugates for ultrasensitive nonisotopic detection [J].
Chan, WCW ;
Nie, SM .
SCIENCE, 1998, 281 (5385) :2016-2018
[9]   LUMINESCENCE AND PHOTOPHYSICS OF CDS SEMICONDUCTOR CLUSTERS - THE NATURE OF THE EMITTING ELECTRONIC STATE [J].
CHESTNOY, N ;
HARRIS, TD ;
HULL, R ;
BRUS, LE .
JOURNAL OF PHYSICAL CHEMISTRY, 1986, 90 (15) :3393-3399
[10]  
COLVIN VL, 1994, NATURE, V370, P354, DOI 10.1038/370354a0