Fourier Transform Infrared Absorbance and Photoluminescence Spectroscopy Studies of CdSe Colloidal Quantum Dot/Conducting Polymer Nanocomposites for Application to Infrared Photodetectors

2007 ◽  
Vol 1015 ◽  
Author(s):  
Kevin R. Lantz ◽  
Adrienne D. Stiff-Roberts
Keyword(s):  
Fourier Transform ◽  
Quantum Dot ◽  
Polymer Nanocomposites ◽  
Conducting Polymer ◽  
Fourier Transform Infrared ◽  
Gaas Substrates ◽  
Long Wave ◽  
Colloidal Quantum Dot ◽  
Spectroscopy Studies ◽  
Long Wave Infrared

AbstractIn this paper we investigate the optical properties of four CdSe colloidal quantum dot/conducting polymer nanocomposites deposited on GaAs substrates using photoluminescence and Fourier transform infrared spectroscopy absorbance. The purpose of this investigation is to find an appropriate electron-conducting polymer for use in a photoconductor that utilizes intraband transitions in the conduction band to detect mid- to long-wave-infrared radiation. As a feasibility demonstration, we fabricate a two-terminal photoconductor and characterize its dark current and spectral responsivity (at 125 K), demonstrating intraband peaks at 0.465 and 0.527 eV, which correspond to 2.67 and 2.35μm.

Long-wave infrared sub-monolayer quantum dot quantum cascade photodetector

2020 ◽  
pp. 1-1
Author(s):  
Zhijian Shen ◽  
Zhuo Deng ◽  
Xuyi Zhao ◽  
Jian Huang ◽  
Lu Yao ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Cascade ◽  
Long Wave ◽  
Long Wave Infrared

Optical Characterization of CdSe Colloidal Quantum Dot/ MEH-PPV Polymer Nanocomposites Spin-cast on GaAs Substrates

2006 ◽  
Vol 939 ◽  
Author(s):  
Adrienne D. Stiff-Roberts ◽  
Abhishek Gupta ◽  
Zhiya Zhao
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Optoelectronic Devices ◽  
Photogenerated Electron ◽  
Polymer Nanocomposite ◽  
Colloidal Quantum Dots ◽  
Infrared Light ◽  
Gaas Substrates ◽  
Conducting Polymer Nanocomposite ◽  
Colloidal Quantum Dot

ABSTRACTThe motivation and distinct approach for this work is the use of intraband transitions within colloidal quantum dots for the detection of mid- (3-5 μm) and/or long-wave (8-14 μm) infrared light. The CdSe colloidal quantum dot/MEH-PPV conducting polymer nanocomposite material is well-suited for this application due to the ∼1.5 eV difference between the corresponding electron affinities. Therefore, CdSe colloidal quantum dots embedded in MEH-PPV should provide electron quantum confinement such that intraband transitions can occur in the conduction band. Further, it is desirable to deposit these nanocomposites on semiconductor substrates to enable charge transfer of photogenerated electron-hole pairs from the substrate to the nanocomposite. In this way, optoelectronic devices analogous to those achieved using Stranski-Krastanow quantum dots grown by epitaxy can be realized. To date, there have been relatively few investigations of colloidal quantum dot nanocomposites deposited on GaAs substrates. However, it is crucial to develop a better understanding of the optical properties of these hybrid material systems if such heterostructures are to be used for optoelectronic devices, such as infrared photodetectors. By depositing the nanocomposites on GaAs substrates featuring different doping characteristics and measuring the corresponding Fourier transform infrared absorbance, the feasibility of these intraband transitions is demonstrated at room temperature.

Fourier transform infrared spectroscopy studies of cyanide ion solutions of dimethylformamide and aqueous dimethylformamide

1993 ◽  
Vol 71 (9) ◽  
pp. 1353-1361 ◽  
Author(s):  
David J. Jobe ◽  
Kenneth Charles Westaway
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Ion Pairs ◽  
Fourier Transform Infrared ◽  
Phase System ◽  
Cyanide Ion ◽  
Two Phase ◽  
Solvated Ions ◽  
Spectroscopy Studies

Fourier transform infrared spectroscopy has been used to investigate the behaviour of HCN and alkali metal and tetraethylammonium cyanides in DMF and aqueous DMF. The cyanide ion exists as free ions and ion pairs in pure DMF but as water-solvated and DMF-solvated ions in aqueous DMF. The aqueous DMF solutions can be treated as a pseudo two-phase system with a distribution coefficient of 0.018 between the aqueous and DMF-rich pseudo phases. A kinetic analysis of the cyanide ion – benzyl chloride reaction in DMF and aqueous DMF has shown that the rate constant for the SN2 reaction is markedly decreased with the addition of as little as 2.5% water. This decrease is primarily due to changes in transition state solvation. The SN2 reactions between cyanide ion and benzylmethyl-4-substituted phenylsulphonium perchlorates in 20% aqueous DMF have also been investigated.

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