个人简介
Dr. Gupta joined Pittsburg State University in the spring of 2013. Before joining Pittsburg State University, he worked as an Assistant Research Professor at Missouri State University, Springfield, MO then as a Senior Research Scientist at North Carolina A&T State University, Greensboro, NC. Dr. Gupta is serving as an Associate Editor and reviewer for several leading science journals. His research focus is in green energy production and storage using nanomaterials, optoelectronics and photovoltaics devices, organic-inorganic hetero-junctions for sensors, nanomagnetism, conducting polymers and composites as well as bio-based polymers, bio-compatible nanofibers for tissue regeneration, scaffold and antibacterial applications and bio-degradable metallic implants. Dr. Gupta has received a number of research grants (over one million dollars) form federal and state agencies such as National Science Foundation (NSF), NSF-Experimental Program to Stimulate Competitive Research (EPSCoR), Department of Energy (DoE), Kansas IDeA Network of Biomedical Research Excellence (K-INBRE), State of Kansas Polymer Chemistry Initiative, etc.
Ph.D., Chemistry, Banaras Hindu University, Varanasi, India, 2005
M.Sc., Chemistry, Banaras Hindu University, Varanasi, India, 1999
B.Sc., Chemistry, Banaras Hindu University, Varanasi, India, 1997
Teaching graduate level courses since 2007. Emphasizing synthesis, characterization and applications of the polymers and nanostructured materials for advanced applications.
研究领域
Project 1: High Efficiency Solar Cells based on Nanostructured Materials
Renewable energy, such as solar, offers major opportunities for satisfying increasing demands for energy by the rapid industrial development and fast growing human population. The challenge for effective use of renewable energy is in the development of high-performance, low-cost, environmentally friendly conversion and storage systems. For this, dye-sensitized solar cells (DSSCs) based on titanium oxide (TiO2) offer a very promising opportunity due to their multiple advantages, such as low cost, light weight, long life and relative ease of tailoring properties. However, their efficiency is still limited by low absorption coefficients, inefficiency of electron transfer and lack of organic materials with suitable bandgap.
The objective of the research project is to improve the efficiency of the solar cell by incorpotation of graphene. We select the dye from red-cabbage because it is cheap, environmentally friendly and very efficient. Its cost/performance coefficient (conversion efficiency/cost of dye) when used in a solar cell should be much higher than that of the corresponding traditional synthetic ruthenium dye. We have investigated the effect of graphene on the efficiency of the solar cells. The high conductivity, high specific surface area, high stability and light weight makes graphene very suitable for these applications.
The effect of light intensity on the solar efficiency of the TiO2/graphene/cabbage dye solar cell was investigated. It was observed that the efficiency of the DSSC increases with increasing the light intensity e.g. the efficiency of the solar cell increases from 0.013% to 0.150% by increase in light intensity from 30 to 100 mW/cm2, respectively. The solar efficiency of the natural dye used in this research was compared with commercial dye (N 719) under similar experimental conditions and observed that the natural (purple cabbage) dye has higher efficiency (0.150%) than N 719 (0.078). It was further evaluated that the efficiency of the fabricated solar cell could improve by incorporating graphene oxide. The efficiency of the TiO2 dye-sensitized solar cell was found to increase from 0.150% to 0.361% by incorporating graphene oxide into purple cabbage dye.
Project 2: High Performance Supercapacitors for Green Energy Storage
The solar cell is an efficient way to produce energy from non-conventioanl sources. However the produced enrgy needs to be stored efficiently also. We are working to develop nanostrctured materials for energy storage. We have developed a facile method for the synthesis of nearly mono-dispersed iron oxide nanocrystals. The average particle size of the iron oxide was estimated to be 8 ± 2 nm (Fig. 3). The observed particle size is in good correlation with particle size estimated using magnetic measurement. Furthermore, these nanocrystals showed bi-functional ferromagnetic and superparamagnetic behavior below and above the blocking temperature, respectively. The potential use of these nanocrystals as an electrode for supercapacitors was examined by investigating the electrochemical behavior of the iron oxide using cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The CV characteristics of the iron oxide electrode showed a typical pseudocapacitive behavior in 3M KOH solution. Moreover, the specific capacitance of 185 F/g at the current of 1mA was observed with excellent cyclic stability. This work provides an ultimate facile method to synthesize nanostructured iron oxide for the applications in next generation energy storage material.
Project 3 Novel Polyurethanes Foams based on Bio-Waste and Renewable Materials
The demand for utilizing renewable and environment friendly resources for chemical and automobile industry is becoming increasingly important due to sustainability. Therefore, the search for a sustainable development based on non-petrochemical feedstock had become one of the major research field. Biomass from plant-derived resources are renewable raw materials and capable of providing a wide variety of starting materials for monomers and polymers. Juicing and peel processing industry (citrus industry) produces bio-waste (orange oil) that contains approximately 90-95% of limonene. The limonene from the renewable bio-waste can be used for preparation of environment friendly polyols. We have been utilizing the limonene based polyols for preparation of rigid polyurethane foams. These polyols were synthesized using number of techniques. These limonene based polyols were structurally characterized using wet methods (hydroxyl number, acid value and viscosity), gel permeation chromatography and spectroscopic methods. The results indicated that high yield of polyols from limonene based materials can be obtained using thiol-ene reaction. These limonene based polyols were used successfully for preparation of rigid polyurethane foams. These foams had regular shape cells and uniform cell size distribution. Thermal studies on these foams indicated that foams were thermally stable up to 250 oC. The glass transition temperature of the foams was higher than 200 oC. These rigid polyurethane foams had high compressive strength and the highest compressive strength of 195 kPa was observed. These foams have good physical-mechanical characteristics and could be suitable for all the applications of rigid polyurethane foams such as thermal insulation of freezers, storage tanks for the chemical and food industries, and packing materials for food industries.
Project 4: Biodegradable Metallic Implants
Craniofacial applications will benefit children who are born with birth defects-cleft palettes, congenital heart defects, etc. Currently children with these defects are fitted with devices that are applied with “nuts and bolts” to the face. These fixtures do not have the ability to "grow" with the child and hence have to be removed and refitted every so often. My research is focused on developing new bio degradable materials such as magnesium with advanced properties. The magnesium and its alloys can be disposed by the body after their work is done, through the blood stream with no side effects. This will have a tremendous impact in the craniofacial and orthopedic markets. We are also working to develop new metallic materials to be introduced as stents in the treatment of cardiovascular problems. In recent work, we have used polymer and ceramic coatings on magnesium to reduce the corrosion rate and improve the bioactivity. Fig.6 shows the SEM images of uncoated magnesium and Mg(OH)2 coated magnesium using hydrothermal technique. The presence of nanostructure on the surface of the magnesium promotes cell attachment and cell growth.
Project 4: Biodegradable Metallic Implants
Craniofacial applications will benefit children who are born with birth defects-cleft palettes, congenital heart defects, etc. Currently children with these defects are fitted with devices that are applied with “nuts and bolts” to the face. These fixtures do not have the ability to "grow" with the child and hence have to be removed and refitted every so often. My research is focused on developing new bio degradable materials such as magnesium with advanced properties. The magnesium and its alloys can be disposed by the body after their work is done, through the blood stream with no side effects. This will have a tremendous impact in the craniofacial and orthopedic markets. We are also working to develop new metallic materials to be introduced as stents in the treatment of cardiovascular problems. In recent work, we have used polymer and ceramic coatings on magnesium to reduce the corrosion rate and improve the bioactivity. Fig.6 shows the SEM images of uncoated magnesium and Mg(OH)2 coated magnesium using hydrothermal technique. The presence of nanostructure on the surface of the magnesium promotes cell attachment and cell growth.
Project 6: Next Generation Nanostructured Organic-Inorganic Hybrid Devices
The overall performance of polymer-based field-effect transistors (FETs), metal–insulator–semiconductor (MIS) diodes, solar cells, and light-emitting diodes (LEDs) is strongly dependent upon the quality of the polymer–dielectric, polymer–metal, and polymer–polymer interfaces. Spin-coating and dip coating techniques are typically used for deposition of thin polymer films; however, these methods do not permit a precise control of the thickness of the films, a necessity for nanoscale polymer-based devices. Matrix-assisted pulsed laser evaporation (MAPLE), a derivative of pulsed laser deposition (PLD), is an alternative method of depositing polymer and biomaterial films that allows homogenous film coverage of high molecular weight organic materials for a layer-by-layer growth without any laser induced damage. In this technique the organic material is dissolved in a volatile non-interacting solvent and frozen at liquid nitrogen temperatures. The frozen target is irradiated by a pulsed laser beam (e.g. KrF excimer laser), whose energy is absorbed by the solvent; the volatile solvent is pumped away and the solute molecules gently evaporate and deposit on the substrate (Fig.9).
Fig. 10 show the transfer characteristics from MAPLE-grown PFB-based FETs on SiO2. The insets show the output characteristics. This research has shown the MAPLE technique to be a viable alternative to spin-coating in the fabrication of device quality organic MIS diodes and FETs. The MAPLE grown sample exhibited less accumulation capacitance and time constant dispersions. The FETs show a consistently better on/off ratio for the MAPLE grown PFB films compared to the spin-coated films. MAPLE grown films provide an added advantage of patterning the active layer with minimum surface modification requirements of the dielectric–polymer interface. This opens up potential applications of the MAPLE technique in nanostructured organic devices.
Project 7: Photosensors based on Heterojuctions
Our group is developing some high performance diodes for photosensor applications. Recently, we have used graphene oxide for photosensing applications. Schottky barrier diode based on graphene oxide (GO) with the structure of Al/GO/n-Si/Al was fabricated. The current–voltage characteristics of the diode were investigated under dark and various light intensity. It was observed that generated photocurrent of the diode depends on light intensity. The transient photocurrent measurement indicated that the Al/GO/n-Si/Al diode was very sensitive to illumination. The photocurrent of the diode increases with increase in illumination intensity. The capacitance–voltage–frequency (C–V–f) measurements indicated that the capacitance of the diode depends on voltage and frequency. The capacitance decreases with increasing frequency due to a continuous distribution of the interface states. These results suggest that the Al/GO/n-Si/Al diode can be utilized as a photosensor.
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Electrical and photoresponse properties of Al/p-CuFeO2/p-Si/Al MTCOS photodiode. R.K. Gupta, M. Cavas, Ahmed A. Al-Ghamdi, Z.H.Gafer, F. El-Tantawy, F. Yakuphanoglu, Solar Energy 92 (2013) 1
Mechanical and corrosion properties of magnesium-hydroxyapatite (Mg-HA) composite thin films. K. Mensah-Darkwa, R.K. Gupta, D. Kumar, J. Mater. Sci. Technol. 29 (2013) 788
Effect of post heat treatment on corrosion resistance of phytic acid conversion coated magnesium. R.K. Gupta, K. Mensah-Darkwa, D. Kumar, J. Mater. Sci. Technol. 29 (2013) 180
Photodiodes based on graphene oxide-silicon junctions. D.-T. Phan, R.K. Gupta, G.-S. Chung, A.A. Al-Ghamdi, Omar A. Al-Hartomy, F. El-Tantawy, F. Yakuphanoglu, Solar Energy 86 (2012) 2961
Synthesis and characterization of nanostructured aluminum borate by sol-gel method. R.K. Gupta, A.A. Al-Ghamdi, O.A. Al-Hartomy, Faten Al-Hazmi, F. El-Tantawy, F. Yakuphanoglu, J. Sol-Gel Sci Technol 64 (2012) 100
Series resistance controlling photosensor of Ag/DNA/p-Si/Al diode. R.K. Gupta, A.A. Al-Ghamdi, O. Al-Hartomi, H. Hasar, F. El-Tantawy, F. Yakuphanoglu, Synth. Met. 162 (2012) 981
Photoconductive Schottky diode based on Al/p-Si/SnS2/Ag for optical sensor applications. R.K. Gupta, F. Yakuphanoglu, Solar Energy 86 (2012) 1539
p-Si/DNA photoconductive diode for optical sensor applications. R.K. Gupta, F. Yakuphanoglu, H. Hasar, Abdulaziz A. Al-Khedhairy, Synth. Met. 161 (2011) 2011
Matrix-assisted pulsed-laser evaporated polymer films in all organic field-effect transistors and metal-insulator-semiconductor diodes. N.B. Ukah, D. Adil, J. Granstrom, R.K. Gupta, K. Ghosh, S. Guha, Org. Electron. 12 (2011) 1580
Vertical exchange bias effects in multilayer thin films based on iron oxide and chromium oxide. R.K. Gupta, K. Ghosh, and P.K. Kahol, Mater. Lett. 65 (2011) 2429
Structural and magnetic properties of epitaxial SnFe2O4 thin films. R.K. Gupta, K. Ghosh, P.K. Kahol, Mater. Lett. 65 (2011) 2149
Glucose stabilized ZnO nanoparticles for biomedical applications. N. Nag, A. Bhattacharya, R.K. Gupta, K. Manivannan, P.K. Kahol, A.K. Wanekaya, R.K. Delong, K. Ghosh, J. Nanoscience Letters 1 (2011) 172
Effect of Particle Size Distributions on Absorbance Spectra of Gold Nanoparticles. J. Doak, R.K. Gupta, K. Manivannan, K. Ghosh, and P.K. Kahol, Physica E 42 (2010) 1605
Electrical properties of rectifying contacts on selectively carrier controlled grown ZnO thin films. Bhattacharya, R.K. Gupta, P.K. Kahol. K. Ghosh, J. Appl. Phys. 108 (2010) 034514
Interface-controlled pulsed-laser deposited polymer films in organic devices. D. Adil, N. B. Ukah, R. K. Gupta, K. Ghosh, and S. Guha, Synth. Met. 160 (2010) 2501
Optical, mechanical and electrical studies of polymer composites based on charge transfer complex of phenothiazine - iodine with polyvinylchloride. S.K. Singh, R.K. Gupta, R.A. Singh, Synth. Met. 159 (2009) 2478
Pulsed laser thin film growth of di-octyl substituted polyfluorene and its co-polymers. R.K. Gupta, K. Ghosh, P.K. Kahol, J. Yoon, S. Guha, Appl. Surf. Sci. 254 (2008) 7069
Inhibition of corrosion by poly (N-hexadecylaniline)/docosanol mixed Langmuir-Blodgett films on copper in sea water. R.K. Gupta, R.A. Singh, Mater. Chem. Phys. 97 (2006) 226
fabrication and characteristics of Schottky diode based on composite organic semiconductors. R.K. Gupta, R.A. Singh, Comp. Sci. Tech. 65 (2005) 677
Preparation and characterization of electrically conducting Langmuir- Blodgett films of poly (N-octadecylaniline). R.K. Gupta, R.A. Singh, J. Colloid Interf. Sci. 285 (2005) 67
Preparation and characterization of polymer composites of polyaniline with poly (vinyl chloride) and polystyrene. R.K. Gupta, R.A. Singh, J. Non Cryst. Solids 351 (2005) 2022
Junction properties of Schottky diode based on composite organic semiconductors. R.K. Gupta, R.A. Singh, J. Mater. Sci.16 (2005) 253
Removal of mercury ions from aqueous solutions by composite of polyaniline with polystyrene. R.K. Gupta, R.A. Singh, S.S. Dubey, Sep. Purif. Technol. 38 (2004) 225
Electrical properties of junction between aluminium and poly (aniline)-poly (vinyl chloride) composite. R.K. Gupta, r.A. Singh, Mater. Chem. Phys. 86 (2004) 279
Semiconducting mixed Langmuir-Blodgett films of poly (N-hexadecylaniline) with stearic acid. R.A. Singh, U. Singh, R.K. Gupta, J. Polym. Mater. 20 (2003) 12
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