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Synthesis and Property of Copper-Impregnated alpha-MnO2 Semiconductor Quantum Dots

IR@CGCRI: CSIR-Central Glass and Ceramic Research Institute, Kolkata

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Title Synthesis and Property of Copper-Impregnated alpha-MnO2 Semiconductor Quantum Dots
 
Creator Mondal, Dheeraj
Paul, Biplab Kumar
Das, Santanu
Bhattacharya, Debopriya
Ghoshal, Debopriyo
Nandy, Papiya
Das, Kaustuv
Das, Sukhen
 
Subject Electronics
 
Description Because of the superior optical and electrical properties, copper-impregnated size tuneable high-temperature stable manganese dioxide semiconductor quantum dots (SQDs) have been successfully synthesized by a modified chemical synthesis technique. Their size-dependent dielectric properties, semiconducting properties, and current voltage (I-V) characteristics have been investigated. X-ray diffraction pattern and Raman spectra confirmed that the required phase is present. Because of the different sintering temperature tuneable size of SQDs has been found and confirmed by high resolution transmission electron microscopy. The band gap energy of the material is found to be 1.25-1.67 eV, measured from Tauc plot using UV-vis absorbance spectrum and their semiconducting properties have been confirmed by the non linear current voltage (I-V) behavior. Most intense green emission peak of photoluminescence (PL) spectroscopy confirms the oxygen vacancy defect state. The stoke shifting of Raman spectra, UV absorption, and PL emission are the footprint of quantum confinement effect. Incorporation of a little amount of Cu in tetragonal hollandite structure of alpha-MnO2 generates strain within that structure. This leads to create sufficient crystal defect state as well as rise in dielectric constant accompanied with low dielectric loss and higher ac conductivity. All these highly desirable properties make the SQDs a potential candidate for developing multifunctional photo-electronic devices. Owing to the tuneable band gap and electronic transport of the SQDs, we realized that the controllable size paves the way for designing SQDs possessing unique properties for optical and electronic device applications. Using this material as a high dielectric separator, a high-performance supercapacitor has been successfully fabricated which can light up 15 light-emitting diodes for 47 min 23 s after charging them only for 30 s.
 
Publisher American Chemical Society
 
Date 2018-11
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://cgcri.csircentral.net/4466/1/biplab.pdf
Mondal, Dheeraj and Paul, Biplab Kumar and Das, Santanu and Bhattacharya, Debopriya and Ghoshal, Debopriyo and Nandy, Papiya and Das, Kaustuv and Das, Sukhen (2018) Synthesis and Property of Copper-Impregnated alpha-MnO2 Semiconductor Quantum Dots. Langmuir, 34 (43). pp. 12702-12712. ISSN 0743-7463
 
Relation http://cgcri.csircentral.net/4466/