scholarly journals A Study on an Organic Semiconductor-Based Indirect X-ray Detector with Cd-Free QDs for Sensitivity Improvement

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6562
Author(s):  
Jehoon Lee ◽  
Hailiang Liu ◽  
Jungwon Kang
Keyword(s):  
Quantum Dots ◽  
Indium Phosphide ◽  
Active Layer ◽  
Electron Acceptor ◽  
Organic Semiconductor ◽  
Environmental Problems ◽  
Hazardous Substances ◽  
X Ray ◽  
Sensitivity Improvement ◽  
Optimized Conditions

In this paper, we studied the optimized conditions for adding inorganic quantum dots (QD) to the P3HT:PC70BM organic active layer to increase the sensitivity of the indirect X-ray detector. Commonly used QDs are composed of hazardous substances with environmental problems, so indium phosphide (InP) QDs were selected as the electron acceptor in this experiment. Among the three different sizes of InP QDs (4, 8, and 12 nm in diameter), the detector with 4 nm InP QDs showed the highest sensitivity, of 2.01 mA/Gy·cm2. To further improve the sensitivity, the QDs were fixed to 4 nm in diameter and then the amount of QDs added to the organic active layer was changed from 0 to 5 mg. The highest sensitivity, of 2.26 mA/Gy·cm2, was obtained from the detector with a P3HT:PC70BM:InP QDs (1 mg) active layer. In addition, the highest mobility, of 1.69 × 10−5 cm2/V·s, was obtained from the same detector. Compared to the detector with the pristine P3HT:PC70BM active layer, the detector with a P3HT:PC70BM:InP QDs (1 mg) active layer had sensitivity that was 61.87% higher. The cut-off frequency of the P3HT:PC70BM detector was 21.54 kHz, and that of the P3HT:PC70BM:InP QDs (1 mg) detector was 26.33 kHz, which was improved by 22.24%.

scholarly journals In Vivo Biotransformations of Indium Phosphide Quantum Dots Revealed by X-Ray Microspectroscopy

2019 ◽  
Vol 11 (39) ◽  
pp. 35630-35640 ◽  
Author(s):  
Giulia Veronesi ◽  
Maria Moros ◽  
Hiram Castillo-Michel ◽  
Lucia Mattera ◽  
Giada Onorato ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Indium Phosphide ◽  
X Ray

scholarly journals Controlling the structures of organic semiconductor–quantum dot nanocomposites through ligand shell chemistry

Soft Matter ◽  
2020 ◽  
Vol 16 (34) ◽  
pp. 7970-7981
Author(s):  
Daniel T. W. Toolan ◽  
Michael P. Weir ◽  
Rachel C. Kilbride ◽  
Jon R. Willmott ◽  
Stephen M. King ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Organic Semiconductor ◽  
Small Angle ◽  
Organic Ligands ◽  
X Ray ◽  
Semiconductor Quantum Dot ◽  
Ligand Shell ◽  
Shell Chemistry ◽  
Nanocrystal Quantum Dots ◽  
Structural Insights

Structural insights via small angle X-ray and neutron (SAXS and SANS, respectively) into how nanocrystal quantum dots (QD) functionalized with organic ligands self-assemble with a small molecule organic semiconductor.

X-ray spectroscopic diagnostics of the structure of quantum dots based on zinc and manganese sulfides and oxides

2017 ◽  
Vol 58 (8) ◽  
pp. 1683-1690
Author(s):  
I. A. Pankin ◽  
◽  
A. N. Kravtsova ◽  
O. E. Polozhentsev ◽  
A. P. Budnyk ◽  
...  
Keyword(s):  
Quantum Dots ◽  
X Ray ◽  
Spectroscopic Diagnostics

scholarly journals A method for studying pico to microsecond time-resolved core-level spectroscopy used to investigate electron dynamics in quantum dots

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tamara Sloboda ◽  
Sebastian Svanström ◽  
Fredrik O. L. Johansson ◽  
Aneta Andruszkiewicz ◽  
Xiaoliang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Injection ◽  
Core Level ◽  
Pump Laser ◽  
Repetition Frequency ◽  
Specific Information ◽  
Single Experiment ◽  
Time Resolved ◽  
X Ray ◽  
Pbs Quantum Dots

AbstractTime-resolved photoelectron spectroscopy can give insights into carrier dynamics and offers the possibility of element and site-specific information through the measurements of core levels. In this paper, we demonstrate that this method can access electrons dynamics in PbS quantum dots over a wide time window spanning from pico- to microseconds in a single experiment carried out at the synchrotron facility BESSY II. The method is sensitive to small changes in core level positions. Fast measurements at low pump fluences are enabled by the use of a pump laser at a lower repetition frequency than the repetition frequency of the X-ray pulses used to probe the core level electrons: Through the use of a time-resolved spectrometer, time-dependent analysis of data from all synchrotron pulses is possible. Furthermore, by picosecond control of the pump laser arrival at the sample relative to the X-ray pulses, a time-resolution limited only by the length of the X-ray pulses is achieved. Using this method, we studied the charge dynamics in thin film samples of PbS quantum dots on n-type MgZnO substrates through time-resolved measurements of the Pb 5d core level. We found a time-resolved core level shift, which we could assign to electron injection and charge accumulation at the MgZnO/PbS quantum dots interface. This assignment was confirmed through the measurement of PbS films with different thicknesses. Our results therefore give insight into the magnitude of the photovoltage generated specifically at the MgZnO/PbS interface and into the timescale of charge transport and electron injection, as well as into the timescale of charge recombination at this interface. It is a unique feature of our method that the timescale of both these processes can be accessed in a single experiment and investigated for a specific interface.

Theoretical and experimental investigation of electronic structure and relaxation of colloidal nanocrystalline indium phosphide quantum dots

2003 ◽  
Vol 67 (7) ◽  
Author(s):  
Randy J. Ellingson ◽  
Jeff L. Blackburn ◽  
Jovan Nedeljkovic ◽  
Garry Rumbles ◽  
Marcus Jones ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Experimental Investigation ◽  
Electronic Structure ◽  
Indium Phosphide

Tuning the Photophysical Properties of Cyclometalated Ir(III) Complexes by a Trifluoroacetyl Group

2012 ◽  
Vol 67 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Bihai Tong ◽  
Jiayan Qiang ◽  
Qunbo Mei ◽  
Hengshan Wang ◽  
Qianfeng Zhang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electron Acceptor ◽  
Photophysical Properties ◽  
Red Shift ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption And Luminescence Spectra ◽  
Homo Lumo

Four cationic Ir(III) complexes, [Ir(dpq)2(bpy)]PF6 (1), [Ir(dpq)2(phen)]PF6 (2), [Ir(tfapq)2- (bpy)]PF6 (3), and [Ir(tfapq)2(phen)]PF6 (4) (dpqH = 2,4-diphenylquinoline, tfapqH = 2-(4ʹ-trifluoroacetylphenyl)- 4-phenylquinoline, bpy = 2,2ʹ-bipyridine, phen = 1,10-phenanthroline) have been synthesized and fully characterized. The structure of 4 was also confirmed by single-crystal X-ray diffraction. The electron-acceptor character of the trifluoroacetyl unit leads to a reduced HOMO-LUMO gap and consequently a red-shift of the UV/Vis absorption and luminescence spectra. The solvophobic character of the trifluoroacetyl unit gives rise to a molecule assembly in solution.

ELECTRON STRUCTURE INVESTIGATIONS OF InGaP/GaAs(100) HETEROSTRUCTURES WITH InP QUANTUM DOTS

2007 ◽  
Vol 06 (03n04) ◽  
pp. 215-219
Author(s):  
E. P. DOMASHEVSKAYA ◽  
V. A. TEREKHOV ◽  
V. M. KASHKAROV ◽  
S. YU. TURISHCHEV ◽  
S. L. MOLODTSOV ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Partial Density ◽  
Edge Structure ◽  
X Ray ◽  
Metal Organic ◽  
Structure Investigations ◽  
First Time ◽  
Inp Quantum Dots

Ultrasoft X-ray emission spectra (USXES) and X-ray absorption near-edge structure (XANES) spectra with the use of synchrotron radiation in the range of P L2,3-edges were obtained for the first time for nanostructures with InP quantum dots grown on GaAs 〈100〉 substrates by vapor-phase epitaxy from metal–organic compounds. These spectra represent local partial density of states in the valence and conduction bands. The additional XANES peak is detected; its intensity depends on the number of monolayers forming quantum dots. Assumptions are made on the band-to-band origin of luminescence spectra in the studied nanostructures.

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