Realization of lasing emission from graphene quantum dots using titanium dioxide nanoparticles as light scatterers

Nanoscale ◽  
2013 ◽  
Vol 5 (5) ◽  
pp. 1797 ◽  
Author(s):  
Hai Zhu ◽  
Wenfei Zhang ◽  
Siu Fung Yu
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Graphene Quantum Dots

scholarly journals Semiconductor Quantum Dots (CdX, X = S, Te, Se) Modify Titanium Dioxide Nanoparticles for Photodynamic Inactivation of Leukemia HL60 Cancer Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Qilin Pan ◽  
Miaomiao Li ◽  
Mucang Xiao ◽  
Yulu He ◽  
Guangyu Sun ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
Visible Light ◽  
Separation Efficiency ◽  
Titanium Dioxide Nanoparticles ◽  
Semiconductor Quantum Dots ◽  
Photogenerated Carrier ◽  
Cdse Qds ◽  
Tio2 Nps ◽  
Targeting Ability

Titanium dioxide nanoparticles (TiO2-NPs) are highly efficient photosensitizers in traditional photodynamic therapy (PDT). The particle size of TiO2-NPs is small, only about 20 nm. However, the demands of ultraviolet light (UV) excitation feature shallow tissue penetration depth and may lead to severe tissue photon damage. Thus, in this research, TiO2-NPs are modified with semiconductor quantum dots (QDs) CdX (X = S, Te, Se) in various methods, such as ultrasonic, hydrothermal, sol-gel, aqueous phase, and hydrolysis precipitation. The transmission electron microscopy (TEM) images show that the size of CdSe-TiO2 is ranging from 6 to 14 nm. The ultraviolet-visible (UV-Vis) spectrum demonstrates that the CdX (X = S, Te, Se) modification can successfully extend the absorption range of TiO2-NPs into a different visible light region. CdSe QDs have the narrowest band gap compared with CdX (X = S, Te, Se) QDs. Visible light-activated CdSe-TiO2 nanocomposite shows the highest PDT inactivation efficiency toward HL60 cells compared with CdX-TiO2. The photogenerated carrier separation efficiency of CdSe-TiO2 nanocomposite is the highest shown in a fluorescence spectrum (FS). Furthermore, when conjugated with folic acid (FA), the prepared FA-CdX-TiO2 (X = S, Se) exhibits excellent cancer-targeting ability during PDT treatment. Optimum PDT efficiency of FA-CdSe-TiO2 indicates that photocatalytic and targeting ability is much higher than pure TiO2 and CdSe-TiO2. Our results provided a detailed investigation on the PDT performance of CdX (X = S, Te, Se) modified TiO2 and may act as a guide for further design of highly targeted performance visible-light response TiO2-NPs.

N-doped graphene quantum dots-functionalized titanium dioxide nanofibers and their highly efficient photocurrent response

2014 ◽  
Vol 29 (13) ◽  
pp. 1408-1416 ◽  
Author(s):  
Xiaotian Wang ◽  
Dandan Ling ◽  
Yueming Wang ◽  
Huan Long ◽  
Yibai Sun ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
Graphene Quantum Dots ◽  
Photocurrent Response ◽  
Highly Efficient ◽  
Doped Graphene ◽  
Image Position

Abstract

Electron Injection from Colloidal PbS Quantum Dots into Titanium Dioxide Nanoparticles

ACS Nano ◽  
2008 ◽  
Vol 2 (11) ◽  
pp. 2206-2212 ◽  
Author(s):  
Byung-Ryool Hyun ◽  
Yu-Wu. Zhong ◽  
Adam C. Bartnik ◽  
Liangfeng Sun ◽  
Hector D. Abruña ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Electron Injection ◽  
Pbs Quantum Dots

scholarly journals Application of doping graphene quantum dots and gold nanoparticles on dye-sensitized solar cells

2021 ◽  
Author(s):  
Kao-Wei Min ◽  
Ming-Ta Yu ◽  
Chi-Ting Ho ◽  
Pin-Ru Chen ◽  
Jenn-Kai Tsai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
Graphene Quantum Dots ◽  
Dye Sensitized Solar Cells ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Dye Sensitized ◽  
Layer Graphene ◽  
Photogenerated Electrons ◽  
Sensitized Solar Cells

The doctor blade coating method is used to prepare dye-sensitized solar cells (DSSCs) and dope the original titanium dioxide (TiO2, P25) photoanode (PA) with single-layer graphene (G), graphene quantum dots (GQDs), and gold (Au) nanoparticles in this research. The results show that doping PAs with G, GQDS, and Au effectively increases the short-circuit current density [Formula: see text], conversion efficiency [Formula: see text], and decreases the internal structure impedance [Formula: see text] of DSSCs. [Formula: see text] increases from 13.62 to 17.02, 15.22, 16.05 mA/cm2, while [Formula: see text] (%) increases from 6.36 to 7.50, 7.08, 7.04% when doping G, GQDs, and Au, respectively. The analysis of Electrochemical Impedance Spectroscopy (EIS) reveals that the doping decreases [Formula: see text] from 11.28 to 8.36, 8.78, 8.54 [Formula: see text], respectively. Then, the titanium dioxide (TiO2)-doped G-GQDs, G-Au, and QDs-Au on DSSCs influence [Formula: see text] that increases to 5.45, 15.37, and 15.31 mA/cm2, respectively. In this case, the values of [Formula: see text] are found to be 7.21%, 7.35%, and 7.00%, while those of [Formula: see text] are 8.44, 8.63, and 9.18 [Formula: see text]. The values of [Formula: see text] and [Formula: see text] are highest but that of [Formula: see text] are lowest when doping with G, which proves that the photoanode of the DSSC effectively activates the photogenerated electrons in the film by doping single-layer graphene and TiO2 captures its electrons through graphene. The decreasing electron–hole recombination rate allows the photogenerated electrons to be quickly transferred to the external circuit. As a result, the efficiency of DSSCs is improved.

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