SK Innovation

My research endeavors align with the PMA strategy, wherein I focus on addressing existing challenges through the development of innovative Processes to synthesize novel Materials for essential Applications. Processes serve as the fundamental backbone for synthesizing advanced materials, and the capability to synthesize materials with desirable characteristics is critical to the success of every application that either enhances our quality of life or provides solutions to existing problems. For example, flame synthesis of TiO₂ nanoparticles is fundamental for synthesizing large quantities of size- and morphology-controlled TiO₂ nanoparticles, which is essential for efficient photocatalysis and optical coatings. The following sections provide a concise overview of my research experience and current research and future outlooks.

1.1 Previous research:

I have developed innovative approaches utilizing aerosolized droplets to engineer materials in-flight or on a surface (photosynthetic pigment[1], perovskites[2, 3], carbon-based materials[4], metal oxides[5, 6] and composites[7, 8]) in-flight for solar energy conversion, sensors, and CO₂ photoreduction.

My work on lead halide perovskite (CH₃NH₃PbI₃) solar cells is a prominent example. Lead halide perovskite solar cells have been extensively researched over the past decade because of their cost-effectiveness, ease of fabrication, and high efficiency. However, challenges with their fabrication and stability in ambient humidity hindered their commercialization. To address this, I developed an innovative approach utilizing aerosolized droplets to engineer the thin film formation and successfully fabricated stable perovskite thin film at ambient humidity (30-50% relative humidity) by controlling the rate of reaction between perovskite precursors[2]. Further, I examined the fundamentals of perovskite synthesis and humidity-induced degradation using in-situ X-ray scattering[9]. The resulting perovskite films and solar cells exhibited remarkable stability for several months in 30-50% relative humidity compared to perovskite films and solar cells fabricated using the conventional spin coating technique. To enhance the efficiency of perovskite solar cells, I utilized surface photovoltage measurement technique to study the carrier selective contact layers[10], which ultimately provided a strategy to enhance voltage extraction and stability through improvements in the NiOx hole transporting layer[11].

1.2 Current research and future outlook:

With rising demand for the miniaturization of devices in several fields, such as – microrobots for drug delivery and precision surgery, microbatteries and components of microelectronics, and environmental microrobots, there is a pressing need for high-resolution printing techniques capable of accommodating a wide range of materials.

Recently, I invented an affordable, compact, and portable high-resolution (few µm – mm) 3D printing technique, called aerosol-based 3D printing (A3DP) (Patent Provisional application is in preparation). This innovative method enables the printing of diverse materials, from single to composite and functionally graded materials and in situ synthesized material. The A3DP equipment is compact, portable, does not require a special environment, and is affordable (currently under $5000, compared to other techniques that cost $500,000). Currently, I am working on fully developing this technology and fundamental understanding of the physics underlying the printing process and determining the impact of processing parameters on the properties. This is achieved through a combined approach of computational Multiphysics modeling encompassing fluid dynamics, heat transfer, and particle transport alongside experimental investigations involving the printing of various single, composite, and functionally graded materials. Regarding this, I have also submitted National Science Foundation (NSF) proposal as the Principal Investigator to support these research efforts, which is under review.

Once fully developed, A3DP technology has the potential to revolutionize multiple industries, including manufacturing, material development, healthcare, energy, communication, defense, and electronics, while also advancing the knowledge of particle-based printing of materials. Additionally, I aim to leverage the A3DP technology’s printing ability for high throughput screening of materials and integrate it with machine learning and molecular dynamics simulation to accelerate the discovery of new materials. In this regard, we are currently focusing on developing materials for thermal management in flexible electronics, a critical concern associated with device downsizing. Lastly, I intend to utilize the A3DP technique to fabricate functional microdevices for biomedical applications, including porous 3D cell culture microdevices for cell growth and freezing.

Using my experience in process development and materials synthesis, I aim to establish a research group that transcends conventional boundaries, harnessing the synergy of experimental and computational power to design high-value materials and devices through simple yet innovative approaches.

2. TEACHING INTEREST:

I started teaching during my undergraduate education as a teaching assistant for Chemical Process Calculation course focused on fundamental mass and energy balance principles. Subsequently, during my doctoral studies, I served as a teaching assistant for courses such as Engineering Analysis of Chemical Systems, Advanced Thermodynamics, and Material Science while also taught classes for the former two courses. To further enhance my teaching abilities, I actively participated in the teaching citation program offered by the Teaching Center at Washington University in St. Louis. This comprehensive program was designed to augment pedagogical skills through engaging workshops, the development and implementation of innovative teaching methods, and the formulation of teaching philosophy. My teaching philosophy revolves around learning through active engagement and collaboration and cultivating a growth mindset without fearing failure.

My teaching interest lie within the domain of chemical engineering, mathematics, and material science and engineering, encompassing courses such as Principle of Engineering Practice, Principles of Chemical Engineering, Chemical Engineering Laboratory, Chemical Reaction Engineering, Transport Phenomena (Mass, Momentum, and Energy Transport), and Thermodynamics. Other interdisciplinary courses I am interested in teaching include Introduction to Material Science, Solid State Chemistry, Synthesis and Design of Materials, Material Characterization Techniques, Structure of Materials, Additive Manufacturing, Composite Material Synthesis, Differential Equations, Calculus, and other Mathematics course. In addition to these focal areas, I aspire to develop courses that delve into Aerosol Science and Technology for Material Design (for both undergraduate and graduate students) and a course on Chemical Engineering in Everyday Life (specifically for undergraduate students). By nurturing a comprehensive range of courses, I aim to contribute to the development of students across various disciplines.

3. REFERENCES

1. Kavadiya, S., et al., Directed assembly of the thylakoid membrane on nanostructured TiO 2 for a photo-electrochemical cell. Nanoscale, 2016. 8(4): p. 1868-1872.
2. Kavadiya, S., et al., Electrospray-Assisted Fabrication of Moisture-Resistant and Highly Stable Perovskite Solar Cells at Ambient Conditions. Advanced Energy Materials, 2017: p. 1700210.
3. de Carvalho, B.A., et al., Highly stable perovskite solar cells fabricated under humid ambient conditions. IEEE Journal of Photovoltaics, 2017. 7(2): p. 532-538.
4. Kavadiya, S., et al., Crumpling of graphene oxide through evaporative confinement in nanodroplets produced by electrohydrodynamic aerosolization. Journal of Nanoparticle Research, 2017. 19(2): p. 43.
5. Haddad, K., et al., Growth of single crystal, oriented SnO 2 nanocolumn arrays by aerosol chemical vapour deposition. CrystEngComm, 2016. 18(39): p. 7544-7553.
6. Lin, L.-Y., et al., A highly sensitive non-enzymatic glucose sensor based on Cu/Cu2O/CuO ternary composite hollow spheres prepared in a furnace aerosol reactor. Sensors and Actuators B: Chemical, 2017.
7. Soundappan, T., et al., Crumpled graphene oxide decorated SnO2 nanocolumns for the electrochemical detection of free chlorine. Applied Nanoscience, 2017. 7(8): p. 645-653.
8. Lin, L.-Y., et al., N-doped reduced graphene oxide promoted nano TiO 2 as a bifunctional adsorbent/photocatalyst for CO 2 photoreduction: Effect of N species. Chemical Engineering Journal, 2017. 316: p. 449-460.
9. Kavadiya, S., et al., Crystal reorientation in methylammonium lead iodide perovskite thin film with thermal annealing. Journal of Materials Chemistry A, 2019. 7(20): p. 12790-12799.
10. Kavadiya, S., et al., Investigation of the Selectivity of Carrier Transport Layers in Wide‐Bandgap Perovskite Solar Cells. Solar RRL, 2021. 5(7): p. 2100107.
11. Boyd, C.C., et al., Overcoming redox reactions at perovskite-nickel oxide interfaces to boost voltages in perovskite solar cells. Joule, 2020. 4(8): p. 1759-1775.