Browsing by Author "R.M. Mehra"

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A simple synthesis route of low temperature CdSe-CdS core-shell quantum dots and its application in solar cell
(Elsevier B.V., 2018) Karan Surana; Ibrahim T. Salisu; R.M. Mehra; Bhaskar Bhattacharya
Synthesis of colloidal semiconductor quantum dots (QDs) has become a major research area in the field of material science. Over the last two decades QDs have been employed successfully in sensitizing the mesoporous semiconductors like TiO2, ZnO etc. in various configurations thus giving birth to a new branch of low cost solar cells known as quantum dot sensitized solar cells (QDSSCs). In this paper we report low temperature synthesis of core-shell CdSe-CdS quantum dots (QDs) using wet chemical technique. A quantum dot solar cell (QDSC) was also prepared with the core-shell QDs as working electrode and a well explored solid polymer electrolyte. The QDSC was characterized and its stability was monitored for a period of two months in laboratory conditions. © 2018 Elsevier B.V.
Corrigendum to “A simple synthesis route of low temperature CdSe–CdS core-shell quantum dots and its application in solar cell” (Optical Materials (2018) 82 (135–140), (S0925346718303318), (10.1016/j.optmat.2018.05.060))
(Elsevier B.V., 2019) Karan Surana; Ibrahim T. Salisu; R.M. Mehra; Bhaskar Bhattacharya
The authors regret having missed the name of the funding agency. The authors are thankful to Council of Scientific and Industrial Research (CSIR) for providing the Senior Research Fellowship (SRF, 9/1078(0002)/18 EMR-I. The authors would like to apologise for any inconvenience caused. © 2019 Elsevier B.V.
Electrical, thermal, and dielectric studies of ionic liquid-based polymer electrolyte for photoelectrochemical device
(SAGE Publications Ltd, 2018) Pawan S Dhapola; Pramod K Singh; B. Bhattacharya; Karan Surana; R.M. Mehra; Meenal Gupta; Abhimanyu Singh; Vijay Singh; Nanda G Sahoo
In this work, solution cast method was adapted for the preparation of 1-ethyl-3-methylimidazolium dicyanamide (EMImDCN)-doped solid polymer electrolyte. Optimum composition of polymer electrolyte (polyethylene oxide + sodium iodide) was treated as the host polymer. The ionic conductivity was further enhanced by adding low-viscosity ionic liquid (IL) EMImDCN. Electrical, thermal, dielectric, and photoelectrochemical properties of polymer host and IL-doped solid polymer electrolyte (ILDPE) are presented in detail. An electrochemical device, that is, dye-sensitized solar cell was fabricated using maximum conducting ILDPE film, which shows short-circuit current density of 0.118 mA/cm2, open-circuit voltage of 0.71 V, and overall efficiency of 0.061% at 1 sun condition. © The Author(s) 2018.
Real-time photovoltaic parameters assessment of carbon quantum dots showing strong blue emission
(Royal Society of Chemistry, 2022) Karan Surana; R.M. Mehra; Saurabh S. Soni; Bhaskar Bhattacharya
The need for replacing conventional sources of energy with renewable ones has been on a swift rise since the last couple of decades. In this context, the progress in third-generation solar cells has taken a good leap in the last couple of years with increasing prospects of high efficiency, stability, and lifetime. Quite recently, a new form of carbon has been discovered accidentally in the form of carbon quantum dots (C QD), which is being pursued actively owing to its chemical stability and luminescent properties. In the current work, we report highly luminescent C QD prepared via a simple hydrothermal route. Transmission electron microscopy revealed an average particle size of 3.4 nm. The prepared C QD were used in a co-sensitized solar cell, where an improvement in the device characteristics was observed. The enhancement in the device characteristics is supported by impedance and electron life-time analysis. Further, the time-dependent analysis of the current and voltage revealed the functioning of the solar cell in real-time condition. © The Royal Society of Chemistry.
Reduced graphene oxide and graded quantum dots for enhanced photovoltaic performance
(Elsevier B.V., 2020) Karan Surana; R.M. Mehra; Bhaskar Bhattacharya
The emergence of quantum dots (QD) and reduced graphene oxide (rGO) has brought significant revolution in the world of third generation solar cells. The ability of QD to harness the power of solar radiation and graphene to swiftly transfer electrons has provided hope in enhancing the cell characteristics. In this paper, CdSe QD have been prepared using mixed solvent for the first time while an extremely simple method was followed for synthesis of CdS QD. The prepared QD were characterized for their absorption, emission, size and structure using various techniques. The prepared quantum dot sensitized solar cell (QDSSC) with configuration rGO/TiO2/CdSe QD/CdS QD/ZnS/I/Pt exhibited efficiency 8 times more than standard dye sensitized solar cell (DSSC). © 2020 Elsevier B.V.