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’s 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 the State of Kansas Polymer Chemistry Initiative, K-INBRE and National Science Foundation, USA.
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.
Courses Taught | Professional Interests | Lab Instruments | Research Interests | Student Accomplishments and Presentations | Publications, Presentations, and Awards
CHEM 320: Introductory Organic ChemistryCHEM 326: Organic Chemistry I LaboratoryCHEM 336: Organic Chemistry II LaboratoryCHEM 620: Polymer ChemistryCHEM 626: Polymer Synthesis and Characterizations LaboratoryCHEM 680: Physical Properties of Polymer
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Dr. Gupta’s research includes optoelectronics and photovoltaics (solar cell) devices, high capacity energy storage devices, polymers and composites, bio-based polymers, biocompatible nanofibers for tissue regeneration, scaffold and antibacterial applications, bio-degradable metallic implants, dilute magnetic semiconductors, ferromagnetic materials and multiferroic materials for sensor and data storage applications
1. Spin Coater
The Laurell WS-650-23 Spin Coater is compact and packed with advanced features. This 650-series coater system will accommodate up to ø150mm wafers and 5" × 5" (127mm × 127mm) substrates, and features a maximum rotational speed of RPM (based on a ø100mm silicon wafer).
The VersaStat 4 utilize high-speed digital to analog converter circuitry, providing instantaneous step changes and pulses to generate the most complex potentiostatic / galvanostatic waveforms. Three high-speed, (500k samples / second) analog to digital converters provide fully synchronized measurements of the cell voltage, cell current and auxiliary voltage input.
The units provide 4-terminal cell connections, which allows great flexibility for the analysis of both high and low impedance cells. In low impedance applications, errors due to cell connection cable impedance may adversely affect the accuracy of results. The use of 4-terminal connections, allows the cell voltage to be measured at the cell terminals, minimizing errors due to cable impedance. The VersaStat 4 provide an optional built-in frequency response analyzer (FRA) that is able to characterize a wide range of electrochemical cells. The FRA is fully integrated into the system allowing high speed switching between DC and EIS measurements.
3. Semiconductor Characterization System
The Model 4200-SCS is a total system solution for electrical characterization of devices, materials and semiconductor processes. This advanced parameter analyzer provides intuitive and sophisticated capabilities for semiconductor device characterization by combining unprecedented measurement sensitivity and accuracy with an embedded Windows-based operating system and the Keithley Interactive Test Environment. It is a powerful single box solution. To get a complete picture of any device or material, three fundamental electrical measurement techniques are required. The Model 4200-SCS offers all three.
4. Solar Simulator
The 66997 Research Series QTH Source includes a lamp housing for QTH lamps, a 69931 Radiometric Power Supply, and 250 W QTH lamp. The lamp housing provides a temperature controlled environment to run the lamp efficiently and holds the condensing optics and rear reflector to collect the lamp radiation. You can power the supply on and off, set the current/power preset and limit, and monitor the current, voltage, power, and operating hours.
5. High Energy Probe Ultrasonication
The Q700 ultrasonicator is the most technologically advanced sonicator available today. A state-of-the-art touch screen interface offers intuitive control and provides a user-friendly experience. The most important feature of a Sonicator is reproducibility. Improved internal circuitry guarantees more efficient operation, sample-to-sample consistency and most importantly, a reliable end result. The Q700 is the only sonicator that offers full amplitude control from 1-100%. This enables greater control of the probe’s intensity, helping to pinpoint the optimum settings for efficient sample processing.
6. High Speed Centrifuge
The Sorvall centrifuge is designed for maximum productivity and high speed up to 15,000 rpm. Class leading acceleration and deceleration rates deliver additional time savings. This is engineered for maximum sample protection. Unlike other centrifuges that require high-maintenance vacuum systems to achieve speed, the Sorvall spins samples at atmospheric pressure, without the need for a vacuum. This superior design minimizes maintenance and helps prevent sample leakage, rotor imbalance and run shut-downs.
In house developed electrospun system provide full control over wide range of potential. This instrument can produce nano-fibers of polymer for various applications such as non-woven cloth, scaffold and biomedical. This technique can produce fibers with high mechanical strength for defense applications. These nanofibers could have amazing characteristics such as very large surface area-to-volume ratio and high porosity with very small pore size and therefore can be also used for many biomedical applications.
Central Facilities at PSU
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Project 1 | Project 2 | Project 3 | Project 4 | Project 5 | Project 6 | Project 7
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.
Fig. 1: The generation and transport of the photoelectrons in the graphene oxide modified TiO2 based DSSC.
Fig. 2: I-V characteristics of DSSCs based on N719 dye, purple cabbage dye, and GO containing purple cabbage dye under 100 mW/cm2 light illumination.
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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.
Fig. 3: TEM images of iron oxide nanoparticles.
Fig. 4: Cycling performance of the iron oxide electrode at constant current of 1mA. The inset shows the first 15 cycles of charge-discharge curves.
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.
Fig.5: Synthesis of polyols based on limonene by thiol-ene “click” chemistry.
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.
Fig.6: SEM images of uncoated magnesium and Mg(OH)2 coated magnesium. The inset figure show higher magnification images.
Project 5: Nanofibers for Enhanced Cell Adhesion and Corrosion Protection for Biodegradable Metallic Implants
Biocompatible polymers have attracted considerable research interest due to their potential in biomedical applications. Nanofibers of such polymers are particularly useful for tissue engineering, scaffolds, and wound healing applications. For biodegradable metallic implants, magnesium is an attractive metal because of its biocompatibility, low density, high specific strength, castability, and appropriate hardness. However, the high degradation rate and low cell growth on magnesium limits its extensive utilization for such applications. One of the most effective methods of reducing the corrosion rate and improving the cell growth is to coat a layer of biocompatible polymers with high surface area on the surface of the magnesium. The coated polymer will reduce the corrosion rate of magnesium by reducing the percolation and permeation of reactive ions in the solution to magnesium substrate, whereas high surface area and porous structure of nanofibers will improve cell adhesion. Polylactic acid is a biocompatible and biodegradable polymer widely used in biomedical applications. We have fabricated nanofibers of polylactic acid embedded with nanoparticles of hydroxyapatite. Since the chemical and crystallographic structure of hydroxyapatite is very similar to the bone, the presence of hydroxyapatite will promote new bone tissue formation and hence bone growth. The degradation rate of the uncoated and coated magnesium substrate was studied using potentiodynamic polarization technique in the phosphate buffered saline (PBS) solution. It was observed that the coating decreases the corrosion rate of magnesium significantly. The corrosion current decrease from 2.98 mA to 1.40 nA, indicating about 103 times improvement in corrosion of magnesium. Biological studies indiacte notoxicity at any concetration and high osteroblast cell adhesion on the nanofibers.
Fig.7: SEM images of nanofibers (left) pure PLA, (right) PLA-20% HA.
Fig.8: % of viability (left) and osteroblast cell (right) growth on the nanofibers of PLA-HA composites.
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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.
Fig. 9: Schematic of the MAPLE technique. Inset shows the chemical structure of PFB.
Fig. 10: Transfer characteristics of MAPLE grown PFB-FET at a drain–source voltage of −30 V. The inset shows the output characteristics.
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.
Fig. 11: Schematic diagram of the fabricated device and the surface morphology of the graphene oxide film.
Fig. 12: The transient photocurrent plot of the Al/n-Si/GO/Al diode.
Student Presentations at Regional and National Conferences:
Presenter: John Candler- Presenting his research on nanostructured materials at International confrence (MRS Fall meeting 2014, San Fransico)
Presenter: Tyler Elmore- Presenting poster at PSU Undergraduate Research Colloquium (April 2014).
Presenter: Eli Mitchell and John Candler, Materials Research Society, San Fransico, 2014
Presenter: Eli Mitchell, PSU Undergraduate research colloquium, Pittsburg, 2014
Presenter: Tyler Elmore, PSU Undergraduate research colloquium, Pittsburg, 2014
Presenter: John Candler, PSU Undergraduate research colloquium, Pittsburg, 2014
Presenter: Eric Williams, PSU Undergraduate research colloquium, Pittsburg, 2014
Presenter: Eli Mitchell, K-INBRE, Kansas City, 2014
Presenter: Eli Mitchell, Capital Research Day, Topeka, 2014
Presenter: John Candler, ACS Regional Meeting, Springfield, 2013
Presenter: Eli Mitchell, ACS Regional Meeting, Springfield, 2013
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Selected Publications | Selected Presentations | Honors, Grants, and Awards
Dr. Gupta has published more than 120 articles in peer-reviewed journals and presented/attended more than 100 national/international conferences. He is a reviewer for various leading science journals. Dr. Gupta has received several internal (university) and external (National Science Foundation) funding to promote research and educational activities.
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Review Editor: Frontiers in Chemistry
Editorial Board Member: Journal of Materials, Thin Films Science and Technology, Journal of Science
Reviewer: Applied Physics A, Advanced Power Technology, Applied Surface Science, Electrochimica Acta, Journal of Alloys and Compounds, Journal of Materials Science: Materials in Electronics, Journal of Non-Crystalline Solids, Materials Chemistry and Physics, Microelectronic Engineering, Materials Letters, Materials Research Bulletin, Materials Science in Semiconductor Processing, etc