Document Detail

Quantum confinement effect of CdSe induced by nanoscale solvothermal reaction.
MedLine Citation:
PMID:  22986805     Owner:  NLM     Status:  Publisher    
We report a novel method, nanoscale solvothermal reaction (NSR), to induce the quantum confinement effect of CdSe on nanostructured TiO(2) by solvothermal route. The time-dependent growth of CdSe is observed in solution at room temperature, which is found to be accomplished instantly by heat-treatment in the presence of solvent at 1 atm. However, no crystal growth occurs upon heat-treatment in the absence of solvent. The nanoscale solvothermal growth of CdSe quantum dot is realized on the nanocrystalline oxide surface, where Cd(NO(3))(2)·4H(2)O and Na(2)SeSO(3) solutions are sequentially spun on nanostructured TiO(2), followed by heat-treatment at temperatures ranging from 100 °C to 250 °C. Size of CdSe increases from 4.4 nm to 5.3 nm, 8.7 nm and 14.8 nm, which results in decrease in optical band gap from 2.19 eV to, 1.95 eV, 1.74 eV and 1.75 eV with increasing the NSR temperature from 100 °C to 150 °C, 200 °C and 250 °C, respectively, which is indicative of the quantum confinement effect. Thermodynamic studies reveal that increase in the size of CdSe is related to increase in enthalpy, for instance, from 3.77 J mg(-1) for 100 °C to 8.66 J mg(-1) for 200 °C. Quantum confinement effect is further confirmed from the CdSe-sensitized solar cell, where onset wavelength in external quantum efficiency spectra is progressively shifted from 600 nm to 800 nm as the NSR temperature increases, which leads to a significant improvement of power conversion efficiency by a factor of more than four. A high photocurrent density of 13.7 mA cm(-2) is obtained based on CdSe quantum dot grown by NSR at 200 °C.
Jin-Wook Lee; Jeong-Hyuk Im; Nam-Gyu Park
Related Documents :
23683235 - Quasiballistic transport of dirac fermions in a bi_{2}se_{3} nanowire.
23381405 - Temperature sensing using the bandgap-like effect in a selectively liquid-filled photon...
24689575 - Study on space charge effect in an electrostatic ion analyzer applied to measure laser ...
24180755 - Infrasonic ray tracing applied to mesoscale atmospheric structures: refraction by hurri...
16486595 - Effect of nuclear quadrupole interactions on the dynamics of two-level systems in glasses.
7308495 - Neural processes in long-term thermal adaptation.
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-18
Journal Detail:
Title:  Nanoscale     Volume:  -     ISSN:  2040-3372     ISO Abbreviation:  Nanoscale     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-9-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101525249     Medline TA:  Nanoscale     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Validation of continuous and noninvasive hemoglobin monitoring by pulse CO-oximetry in Japanese surg...
Next Document:  Exploring doxorubicin localization in eluting TiO(2) nanotube arrays through fluorescence correlatio...