Artificial Photosynthesis Using Semiconductor Nanomaterials

The mitigation of steadily increasing atmospheric CO2 might well be the major global scientific challenge of the twenty-first century. Carbon capture is an important issue in Alberta, a jurisdiction with a large carbon footprint. The use of CO2 as a feedstock for energy storage is also of interest. An efficient sunlight-driven CO2 reduction process that produces alcohols or hydrocarbons from H2O+CO2 can store energy in the form of chemical bonds - an alternative to hydrogen-based energy storage. Natural photosynthesis is the chemical reaction on which life is based, but is inefficient in terms of conversion of light into chemical energy (global efficiency ~0.2%). Semiconductor nanomaterial-based artificial photosynthesis will enable efficiencies several times higher than natural photosynthesis. Artificial photosynthesis is complex with eight electron transfer steps, thus rendering the reaction vulnerable to energetic losses at every step. The mechanistic routes governing the formation of desirable end-products are not fully established. And yet, there is huge potential; the combination of government levied carbon taxes (ALBERTA: currently $20/tonne of CO2, set to increase to $30/tonne by 2018 and CANADA: $50/tonne of CO2 by 2020) and highly efficient catalysts can render CO2 reduction profitable in the not-too-distant future. Companies that package and sell carbon offsets to big and small CO2 emitters are very interested in this technology.


In the last four years of research, binary and ternary heterojunctions of the following four components have been shown by us to be particularly effective photocatalysts for artificial photosynthesis:


(i) Carbon nitrides: These are pi-conjugated polymers with a graphitic framework. They are easily exfoliated to form two-dimensional sheets.  The leading member of this family is g-C3N4 whose bandgap of 2.6 eV is not optimal for solar energy harvesting.  The Shankar Lab synthesized a new graphitic polymer with the chemical formula C3N5 which had a more optimal electronic bandgap of 1.7 eV.  Information about the properties and performance of C3N5 was disseminated in a 2019 article in the prestigious Journal of the American Chemical Society in 2019 (https://doi.org/10.1021/jacs.9b00144) where it has since been cited over 200 times to date.


(ii) Plasmonic nanomaterials: Nanostructured coinage metals (Au, Ag, Cu) generate hot carriers that can be used to drive chemical reactions.  However, hot carriers represent a short-lived exotic species and our research has advanced knowledge and understanding in this area. By controlling the shape, size and dielectric environment of coinage metal nanoparticles, we have shown an ability to increase the selectivity for a C2+ product (https://doi.org/10.1021/acsami.0c21067) and harvest hot holes (harder to do) as well as hot electrons in plasmonic heterojunctions (https://doi.org/10.1021/acsami.1c10698). Our work on tuning the reaction pathway in high rate CO2 photoreduction was published in 2020 in the high impact journal Applied Catalysis B: Environmental (https://doi.org/10.1016/j.apcatb.2020.118644) and has been cited 55 times to date. We have also shown a way to decrease dependence on noble metals for plasmonics by highlighting hot carrier-driven photochemistry in transition metal nitrides (https://doi.org/10.3390/catal11111374).


(iii) Metal oxides:  We started the FES project with TiO2, an old workhorse of solar energy research which is limited by its large electronic bandgap of 3.0-3.2 eV.  Recently, we have moved on to multi-element quinary and senary perovskite oxides with bandgaps as low as 1.5 eV (https://doi.org/10.1088/1361-6528/abedec).  The concept of oxide perovskites is being pursued collaboratively with the University of Calgary and machine learning based methods are being used to find optimal compositions. 


(iv) Halide perovskites: CsPbBr3 nanocrystals coated with a protective layer of carbon nitride gave us high performance in both photoelectrochemical water splitting and CO2 photoreduction. This work was disseminated in a 2022 article in Applied Surface Science (https://doi.org/10.1016/j.apsusc.2022.153276).


We have a wide network of local and international research collaborators.  We are now seeking to partner with Canadian SMEs to increase the technology readiness level of our catalysts.  It is noteworthy that three of our four platform material systems namely carbon nitrides, transition metal oxides and transition metal nitrides are made of earth-abundant elements, are photochemically stable, are relatively inexpensive to manufacture and lend themselves to "scale up". 

Alberta Graduate Excellence Scholarship

Sheng Zeng

Award

Alberta Graduate Excellence Scholarship

Sheng Zeng

Award

Alberta Innovates Graduate Student Scholarship

Narendra Chaulagain

Award

Best Poster Award (Symposium N)

Ryan Kisslinger

Award

CSC'2022 Travel Award

Narendra Chaulagain

Award

Canada Graduate Scholarships - Doctoral Award

Ryan Kisslinger

Award

Canada Graduate Scholarships - Doctoral Award

Ajay Manuel

Award

Doctoral Prize of Distinction

Ajay Manuel

Award

Doctoral Recruiting Scholarship

Harshitha Rajashekhar

Award

Doctoral Recruiting Scholarship

Damini Vrushabendrakumar

Award

Doctoral Recruitment Scholarship

Navneet Kumar

Award

Gerald J. Maier/NOVA Chemicals Corporation Graduate Recruitment Award

Md Masud Rana

Award

Graduate Recruitment Scholarship

Md Masud Rana

Award

Graduate Scholarship

Ujwal Thakur

Award

Graduate Student Scholarship

Ryan Kisslinger

Award

MITACS Globalink

Harshitha Rajashekhar

Award

MITACS Globalink Research Award

Ehsan Vahidzadeh

Award

NSERC Scholarship Supplementary Award

Ryan Kisslinger

Award

NSERC USRA

Award

Undergraduate Student Research Award (USRA)

Xinkai Xu

Award

Undergraduate Student Research Award (USRA)

Dipesh Aggarwal

Award

Undergraduate Student Research Award (USRA)

Catlin Letendre

Award

Undergraduate Student Research Award (USRA)

Darren Dahunsi

Award

Undergraduate Student Research Award (USRA)

Collin VanEssen

Award

Undergraduate Student Research Award (USRA)

Phillip Suwan Kirwin

Award

2D C-N Semiconductors: Graphitic, Earth-Abundant Photocatalysts with Tunable Bandgaps

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Ehsan Vahidzadeh

Conference/Symposium/Workshop Contribution

A Rational Design of Cu2O-SnO2 Core-Shell Catalyst for Highly Selective CO2-to-CO Conversion

Karthik Shankar, Jingli Luo, Steven Bergens, Bin Hua, Meng Li, Sheng (Shawn) Nian Zhang, Shaochen Ding

Scholarly Refereed Journal

A Review on Photocatalytic CO2 Reduction using Perovskite Oxide Nanomaterials

Karthik Shankar, Ujwal Thakur, Sheng Zeng, Piyush Kar

Scholarly Refereed Journal

ATUMS visiting PhD student

Visiting Researcher (incoming)

Air- and water-stable halide perovskite nanocrystals protected with nearly-monolayer carbon nitride for CO 2 photoreduction and water splitting

Karthik Shankar, Pawan Kumar, Sheng Zeng, Devika Laishram

Scholarly Refereed Journal

All-solid-state formation of titania nanotube arrays and their application in photoelectrochemical water splitting

Karthik Shankar, Pawan Kumar, Najia Mahdi, Yun Zhang

Scholarly Refereed Journal

An Ultrasensitive Fluorescent Paper Based Acidic Gas Sensing Platform

Karthik Shankar, Damini Vrushabendrakumar, Harshitha Rajashekhar, Narendra Chaulagain, Sachin Kadian

Conference/Symposium/Workshop Contribution

Anodic Fabrication of n- and p-type Metal Oxide Nanostructures on Non-Native Substrates

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Saralyn Riddell

Conference/Symposium/Workshop Contribution

Application of Machine Learning and Computer Vision in Obtaining the Optical Response of Plasmonic Heterostructures

Karthik Shankar

Conference/Symposium/Workshop Contribution

Application of One Dimensional Metal Oxides as Electron transport layer for High Efficiency Halide Perovskite Solar Cells (HPSCs)

Karthik Shankar, Ujwal Thakur

Conference/Symposium/Workshop Contribution

Application of TiO2 Nanotubes and Nanowires in Photocatalytic CO2 Reduction

Karthik Shankar, Ujwal Thakur, Piyush Kar

Conference/Symposium/Workshop Contribution

Arrays of TiO2 nanorods embedded with fluorine doped carbon nitride quantum dots (CNFQDs) for visible light driven water splitting

Karthik Shankar, Ryan Kisslinger, Sahil Patel, Ujwal Thakur, Pawan Kumar, Kazi Alam, Sheng Zeng, Piyush Kar

Scholarly Refereed Journal

Artificial Neural Network-Based Prediction of the Optical Properties of Spherical Core\textendash Shell Plasmonic Metastructures

Karthik Shankar, Ehsan Vahidzadeh

Scholarly Refereed Journal

Asymmetric Multipole Plasmon-Mediated Catalysis Shifts the Product Selectivity of CO 2 Photoreduction toward C2+ Products

Karthik Shankar, Pawan Kumar, Ehsan Vahidzadeh, Sheng Zeng, Saralyn Riddell

Scholarly Refereed Journal

Atomistic insights on Halide Composition in Mixed Halide Perovskite Systems: 207Pb solid-state NMR perspective

Karthik Shankar, Sahil Patel, Benjamin Wiltshire, Vladimir K Michaelis, Abhoy Karmakar

Conference/Symposium/Workshop Contribution

Au-Nanoparticle Embedded TiO2 Nanotube Arrays for Sensing, Photocatalysis and Nonlinear Optics

Karthik Shankar

Conference/Symposium/Workshop Contribution

C3N5: A Low Bandgap Semiconductor Containing an Azo-linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent Applications

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Kazi Alam, Ehsan Vahidzadeh, Najia Mahdi, Piyush Kar, Vladimir K Michaelis, Ankur Goswami, Guy Bernard

Scholarly Refereed Journal

CO2 photoreduction using earth abundant transition metal oxides & chalcogenides

Karthik Shankar

Conference/Symposium/Workshop Contribution

CO2 reduction performance of TiO2 nanotube-based heterojunction photocatalysts

Karthik Shankar, Ehsan Vahidzadeh, Piyush Kar

Conference/Symposium/Workshop Contribution

CVD grown nitrogen doped graphene is an exceptional visible-light driven photocatalyst for surface catalytic reactions

Karthik Shankar, Pawan Kumar, Ehsan Vahidzadeh, Sheng Zeng, Najia Mahdi, Ankur Goswami

Scholarly Refereed Journal

Cellulose nanocrystals conjugated with metallophthalocyanines: Applications in visible-light driven photocatalysts and memory devices

Narendra Chaulagain

Master Thesis

Chalcogenide Semiconductor Nanomaterials for Photocatalytic Applications

Karthik Shankar, Ujwal Thakur, Piyush Kar

Conference/Symposium/Workshop Contribution

Characterization of Carrier Dynamics in Metal Oxide Nanostructures and Tellurophenes

Benjamin Wiltshire

Master Thesis

Charge Separation and Transport in Functional Heterojunctions Based on Solution-Grown TiO2 Nanotube & Nanowire Arrays

Karthik Shankar

Conference/Symposium/Workshop Contribution

Charge-accumulation-induced mixed photocorrosion in the Z-scheme PEC system

Karthik Shankar, Jingli Luo, Steven Bergens, Chenyu Xu, Mengnan Zhu, Pengfei Sui

Conference/Symposium/Workshop Contribution

Collaborative Ultrafast Spectroscopic Laser (CUSL) facility

Karthik Shankar, Al Meldrum, Juli Gibbs, Frank Hegmann

Misc: Canada Foundation for Innovation (CFI) John R. Evans Leade

Composition-Tunable Formamidinium Lead Mixed Halide Perovskites via Solvent-Free Mechanochemical Synthesis: Decoding the Pb Environments Using Solid-State NMR Spectroscopy

Karthik Shankar, Sahil Patel, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar

Scholarly Refereed Journal

Consistently High Voc Values in p-i-n Type Perovskite Solar Cells Using Ni3$\mathplus$-Doped NiO Nanomesh as the Hole Transporting Layer

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Piyush Kar, Saralyn Riddell, Ankur Goswami, Spencer Savela

Scholarly Refereed Journal

Copper Sulfide Nanostructures and their utility in Photocatalytic CO2 Reduction

Karthik Shankar, Piyush Kar, Yun Zhang

Conference/Symposium/Workshop Contribution

Core-shell titanium dioxide-titanium nitride nanotube arrays with near-infrared plasmon resonances

Karthik Shankar, Najia Mahdi, Piyush Kar

Scholarly Refereed Journal

Core-shell titanium dioxide@titanium nitride nanotube arrays for optical limiters and near-infrared sensitive optoelectronics

Karthik Shankar, Ryan Kisslinger, Sheng Zeng, Ajay Manuel, Saralyn Riddell

Conference/Symposium/Workshop Contribution

Detecting Charge Separation in Optoelectronic Materials and Devices Using Planar Microwave Resonators: An Overview

Karthik Shankar, Md Masud Rana

Conference/Symposium/Workshop Contribution

Development of life cycle GHG emissions of high-performance mono-crystalline titanium dioxide nanorod based perovskite solar cells

Karthik Shankar, Ujwal Thakur, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Other Event

Distinguishing between deep trapping transients of electrons and holes in TiO 2 nanotube arrays using planar microwave resonator sensor

Karthik Shankar, Najia Mahdi

Scholarly Refereed Journal

Doped Graphene and Graphenic Semiconductors: Mass Producible, Earth- Abundant Materials for Photocatalysis and Photovoltaics

Karthik Shankar

Conference/Symposium/Workshop Contribution

Double peak emission in lead halide perovskites by self-absorption

Karthik Shankar

Scholarly Refereed Journal

Earth abundant 1D & 2D nanomaterial sensitized TiO2 nanotube arrays for visible light driven water-splitting

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Pawan Kumar, Kazi Alam

Conference/Symposium/Workshop Contribution

Effect of morphology on the photoelectrochemical performance of nanostructured Cu2O photocathodes

Karthik Shankar, Pawan Kumar, Kazi Alam, Ehsan Vahidzadeh, Sheng Zeng, Piyush Kar, Ajay Manuel, Lian Shoute

Scholarly Refereed Journal

Effect of sulfur‑doped graphene quantum dots incorporation on morphological, optical and electron transport properties of CH3NH3PbBr3 perovskite thin films

Karthik Shankar, Narendra Chaulagain, Sachin Kadian

Scholarly Refereed Journal

Electrochemically Dismantled Perovskite with Cooperative Catalysis for CO 2-to-Formate Conversion

Karthik Shankar, Jingli Luo, Steven Bergens, Hongbo Zeng, Minrui Gao, Chenyu Xu, Bowen Zhang, Mengnan Zhu, Pengfei Sui

Conference/Symposium/Workshop Contribution

Electrochemically reconstructed perovskite with cooperative catalytic sites for CO 2-to-formate conversion

Karthik Shankar, Steven Bergens, Hongbo Zeng, Chenyu Xu, Mengnan Zhu, Pengfei Sui

Article in professional or trade journals

Engineering Stable, High Efficiency Flexible Halide Perovskite Solar Cells

Karthik Shankar, Ujwal Thakur, Piyush Kar

Conference/Symposium/Workshop Contribution

Enhanced Charge Separation in g-C3N4–BiOI Heterostructures for Visible Light Driven Photoelectrochemical Water Splitting

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Kazi Alam, Sheng Zeng, Piyush Kar

Scholarly Refereed Journal

Enhancing Photocatalyst and Solar Cell Performance Using Nanophotonic Effects

Karthik Shankar, Ujwal Thakur, Sheng Zeng, Piyush Kar

Conference/Symposium/Workshop Contribution

Exploiting Nanophotonics and Plasmonic Hot Electrons for the Production of Solar Fuels

Karthik Shankar, Ehsan Vahidzadeh, Sheng Zeng, Ajay Manuel

Conference/Symposium/Workshop Contribution

Exposing Halide-Mixing in Hybrid Perovskite Materials Using Solid-State NMR

Karthik Shankar, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar, Guy Bernard

Conference/Symposium/Workshop Contribution

Exposing Halide-Mixing in Next-Generation Hybrid Organic-Inorganic Perovskite Materials using Solid-State NMR

Karthik Shankar, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar, Guy Bernard

Conference/Symposium/Workshop Contribution

Flame Annealed TiO2 and its Heterojunctions for the Production of Solar Fuels

Karthik Shankar, Kazi Alam

Conference/Symposium/Workshop Contribution

Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems Based on SnIP

Karthik Shankar, Ujwal Thakur, Pawan Kumar

Scholarly Refereed Journal

Focused Session on "Microwave and Hot Carrier Sensors" at IEEE Sensors 2022, Dallas TX

Karthik Shankar

Conference/Symposium/Workshop Contribution

Harvesting Hot Holes in Plasmon-Coupled Ultrathin Photoanodes for High-Performance Photoelectrochemical Water Splitting

Karthik Shankar, Pawan Kumar, Kazi Alam, Ehsan Vahidzadeh, Sheng Zeng, Saralyn Riddell, Narendra Chaulagain

Scholarly Refereed Journal

Helped organize the 2D Materials symposium at ICEE'2020

Karthik Shankar

Conference/Symposium/Workshop Contribution

Heterojunctions based on 2D Carbon-Based Semiconductor Nanomaterials for Photocatalysis and Photovoltaics

Karthik Shankar

Conference/Symposium/Workshop Contribution

Heterojunctions based on 2D Carbon-Based Semiconductor Nanomaterials for Photocatalysis and Photovoltaics

Karthik Shankar

Conference/Symposium/Workshop Contribution

Heterojunctions of halogen-doped carbon nitride nanosheets and BiOI for sunlight-driven water-splitting

Karthik Shankar, Pawan Kumar, Kazi Alam, Ehsan Vahidzadeh, Sheng Zeng, Piyush Kar, Ankur Goswami

Scholarly Refereed Journal

Heterojunctions of mixed phase TiO2 nanotubes with Cu, CuPt, and Pt nanoparticles: interfacial band alignment and visible light photoelectrochemical activity

Karthik Shankar, Ryan Kisslinger, Najia Mahdi, Piyush Kar, Yun Zhang

Scholarly Refereed Journal

Hexagonal Double Perovskite Cs2AgCrCl6

Arthur Mar, Karthik Shankar, Anton Oliynyk, Jan Poehls

Scholarly Refereed Journal

High Rate CO2 Photoreduction Using Flame Annealed TiO2 Nanotubes

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Pawan Kumar, Kazi Alam, Ehsan Vahidzadeh, Sheng Zeng, Najia Mahdi, Piyush Kar, Ajay Manuel, Yun Zhang

Scholarly Refereed Journal

High Selectivity CO2 Photoreduction Using Earth Abundant Semiconductor Photocatalysts

Karthik Shankar, Ryan Kisslinger, Ehsan Vahidzadeh, Sheng Zeng

Conference/Symposium/Workshop Contribution

High Voc halide perovskite solar cells using optimized charge transport layers

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Sheng Zeng, Ankur Goswami

Conference/Symposium/Workshop Contribution

Highly Structured Nanomaterials for High Performance Photocatalysts and Solar Cells

Karthik Shankar

Conference/Symposium/Workshop Contribution

Hot Carrier Assisted Plasmonic Photocatalysis

Ajay Manuel

Doctoral Thesis/Dissertation

Hot Carrier-Mediated Generation of Solar Fuels Using Plasmon-Semiconductor Nanoheterojunctions

Karthik Shankar

Conference/Symposium/Workshop Contribution

Hot Electron-mediated Plasmonic Photocatalysis Using Heterojunctions of Noble Metal Nanoparticles and Semiconductor Nanowires/Nanotubes

Karthik Shankar

Conference/Symposium/Workshop Contribution

Hot Electrons in TiO2-Noble Metal Nano-Heterojunctions: Fundamental Science and Applications in Photocatalysis

Karthik Shankar, Ajay Manuel

Scholarly Refereed Journal

Hybrid Lead Mixed-Halide Perovskites: Mechanochemical Synthesis and Solid-State NMR Study

Karthik Shankar, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar, Guy Bernard

Conference/Symposium/Workshop Contribution

Instantaneous Property Prediction and Inverse Design of Plasmonic Nanostructures Using Machine Learning: Current Applications and Future Directions

Karthik Shankar, Dipesh Aggarwal, Xinkai Xu

Scholarly Refereed Journal

Introduction to plasmonics and the MEMS application of surface plasmons

Karthik Shankar

Conference/Symposium/Workshop Contribution

Investigating the Tetragonal-to-Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

Karthik Shankar

Scholarly Refereed Journal

Life cycle assessment of high-performance mono-crystalline titanium dioxide nanorod based perovskite solar cells

Amit Kumar, Karthik Shankar, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Conference/Symposium/Workshop Contribution

Life cycle assessment of high-performance monocrystalline titanium dioxide nanorod-based perovskite solar cells

Amit Kumar, Karthik Shankar, Ujwal Thakur, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Scholarly Refereed Journal

Life cycle assessment of mono-crystalline TiO2 nanorod array based halide perovskite solar cells

Amit Kumar, Karthik Shankar, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Conference/Symposium/Workshop Contribution

Life cycle environmental and techno-economic assessment of perovskite solar cells.

Amit Kumar, Karthik Shankar, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Conference/Symposium/Workshop Contribution

Light-induced Energy Production Using Plasmonic Photocatalysis

Ehsan Vahidzadeh

Doctoral Thesis/Dissertation

MITACS Globalink Summer Intern from Germany

Timotheus Hohl

Visiting Researcher (incoming)

MITACS Globalink Summer Intern from India

Priyash Barya

Visiting Researcher (incoming)

Mechanochemical Synthesis of Methylammonium Lead Mixed\textendash Halide Perovskites: Unraveling the Solid-Solution Behavior Using Solid-State NMR

Karthik Shankar, Sahil Patel, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar

Scholarly Refereed Journal

Melanin-based electronics: From proton conductors to photovoltaics and beyond

Karthik Shankar, Ehsan Vahidzadeh

Scholarly Refereed Journal

Mimicking photosynthesis in nature using metal nanoparticles

Ajay Manuel

Misc: Blog Post

Multiscale modeling of active layer of hybrid organic-inorganic solar cells for photovoltaic applications by means of density functional theory and integral equation theory of molecular liquids

Karthik Shankar

Scholarly Refereed Journal

Nanophotonic enhancement and improved electron extraction in perovskite solar cells using near-horizontally aligned TiO2 nanorods

Karthik Shankar, Ryan Kisslinger, Sahil Patel, Ujwal Thakur, Pawan Kumar, Sheng Zeng, Piyush Kar, Yun Zhang, Al Meldrum, Ankur Goswami

Scholarly Refereed Journal

Nanosheets of carbon nitride and nitrogen doped graphene for photovoltaics and photocatalysis

Karthik Shankar

Conference/Symposium/Workshop Contribution

Nanostructured Plasmonic Heterojunctions for the Production of Solar Fuels

Karthik Shankar

Conference/Symposium/Workshop Contribution

Nanowire Electron Transport Layers (ETLs) for High Efficiency Halide Perovskite Solar Cells (HPSCs)

Karthik Shankar, Ujwal Thakur

Conference/Symposium/Workshop Contribution

New frontiers in the anodic synthesis of self-organized TiO2 nanotube arrays

Karthik Shankar, Ryan Kisslinger, Pawan Kumar, Sheng Zeng

Conference/Symposium/Workshop Contribution

Noble Metal Free, Visible Light Driven Photocatalysis Using TiO2 Nanotube Arrays Sensitized by P-doped C3N4 Quantum Dots

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Pawan Kumar, Kazi Alam, Sheng Zeng, Piyush Kar, Ajay Manuel, Yun Zhang, Vladimir K Michaelis, Guy Bernard

Scholarly Refereed Journal

Nonlithographic Formation of Ta2O5 Nanodimple Arrays Using Electrochemical Anodization and Their Use in Plasmonic Photocatalysis for Enhancement of Local Field and Catalytic Activity

Karthik Shankar, Ryan Kisslinger, Saralyn Riddell

Scholarly Refereed Journal

Novel Anodized Metal Oxide Nanostructures on Non-Native Substrates

Ryan Kisslinger

Doctoral Thesis/Dissertation

Novel Materials for Clean and Sustainable Energy CHALLENGE PROGRAM WORKSHOP

Karthik Shankar

Conference/Symposium/Workshop Contribution

One Dimensional Metal Oxide Semiconductors as Electron Transport Layers for High Efficiency Halide Perovskite Solar Cells (HPSCs)

Karthik Shankar, Ujwal Thakur, Sheng Zeng, Al Meldrum

Conference/Symposium/Workshop Contribution

One-Dimensional Solution-Processed TiO2 Nanostructures for Use in Photovoltaics, Photocatalysis, and Microwave Resonator Sensors

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Najia Mahdi, Piyush Kar, Benjamin Wiltshire

Conference/Symposium/Workshop Contribution

Optical Control of Selectivity of High Rate CO2 Photoreduction Via Interband- or Hot Electron Z-Scheme Reaction Pathways in Au-TiO2 Plasmonic Photonic Crystal Photocatalyst

Karthik Shankar, Ryan Kisslinger, Collin VanEssen, Pawan Kumar, Ehsan Vahidzadeh, Sheng Zeng, Najia Mahdi, Piyush Kar, Yun Zhang, Ankur Goswami

Scholarly Refereed Journal

Optical Modelling of Non-Lithographically Fabricated Photonic Crystal- and Plasmonic- Photocatalysts

Karthik Shankar, Collin VanEssen, Ehsan Vahidzadeh, Sheng Zeng, Piyush Kar, Ajay Manuel, Yun Zhang

Conference/Symposium/Workshop Contribution

Optical Properties of Anatase and Rutile Phase TiO2 Nanotubes

Yun Zhang

Master Thesis

Optical and Optothermal Metamaterials: Fabrication, Characterization and Applications in Sensing and Energy Harvesting

Karthik Shankar

Conference/Symposium/Workshop Contribution

Organic-Inorganic Nanohybrid Materials for Photovoltaic Applications

Karthik Shankar

Conference Proceedings

Phase Evolution in Methylammonium Tin Halide Perovskites with Variable Temperature Solid-State 119Sn NMR Spectroscopy

Karthik Shankar, Vladimir K Michaelis, Michelle Ha, Abhoy Karmakar, Guy Bernard

Scholarly Refereed Journal

Photocatalytic mechanism control and study of carrier dynamics in CdS@C3N5 core-shell nanowires

Karthik Shankar, Pawan Kumar, Kazi Alam, Ajay Manuel, Frank Hegmann, Vladimir K Michaelis, Charles Jensen, Guy Bernard, David Purschke, Riley Hooper, Narendra Chaulagain, John Garcia

Scholarly Refereed Journal

Planar microwave resonator with electrodeposited ZnO thin film for ultraviolet detection

Karthik Shankar, Najia Mahdi, Masoud Baghelani

Scholarly Refereed Journal

Plasmon Enhanced Titanium Dioxide Nanotubes for Nanophotonics, Non-linear Optics, and Photocatalysis

Sheng Zeng

Doctoral Thesis/Dissertation

Plasmon-Enhanced Semiconductor Photocatalysis: Using Hot Electrons to Drive Chemical Reactions

Karthik Shankar

Conference/Symposium/Workshop Contribution

Plasmonic Catalysis: Fundamentals, Materials, Methods And Challenges

Karthik Shankar

Conference/Symposium/Workshop Contribution

Plasmonic Photocatalysis for the Generation of Solar Fuels

Karthik Shankar

Conference/Symposium/Workshop Contribution

Plasmonic Photonic Crystal Photocatalysts Consisting of TiO2 Nanotube Arrays Decorated/Embedded with Noble Metal Nanoparticles

Karthik Shankar, Sheng Zeng

Conference/Symposium/Workshop Contribution

Plasmonic photocatalysis and SERS sensing using ellipsometrically modeled Ag nanoisland substrates

Karthik Shankar, Kazi Alam, Sheng Zeng, Ajay Manuel, Saralyn Riddell, Priyash Barya

Scholarly Refereed Journal

Plasmonic photocatalysis for high selectivity CO2 photoreduction and water-splitting driven by visible photons

Karthik Shankar

Conference/Symposium/Workshop Contribution

Plexcitonics – Fundamental principles and optoelectronic applications

Karthik Shankar, Aaron Kirkey, Najia Mahdi, Ajay Manuel

Scholarly Refereed Journal

Preferentially Oriented TiO2 Nanotube Arrays on Non-Native Substrates and Their Improved Performance as Electron Transporting Layer in Halide Perovskite Solar Cells

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Sheng Zeng, Yun Zhang, Saralyn Riddell, Ankur Goswami, Darren Dahunsi

Scholarly Refereed Journal

Preferentially Oriented Zn-Doped TiO2 Nanotubes Grown on Non-Native Substrates

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur

Conference/Symposium/Workshop Contribution

Robust Plasmonic Glasses using nanoporous TiO2 embedded with Au nanoparticles

Karthik Shankar, Ryan Kisslinger, Kazi Alam, Sheng Zeng, Ajay Manuel

Conference/Symposium/Workshop Contribution

SERB Overseas Visiting Doctoral Fellowship

Sachin Kadian

Visiting Researcher (incoming)

SERC Overseas Visiting Doctoral Fellowship

Devika Laishram

Visiting Researcher (incoming)

Solution Processed Earth-Abundant Semiconductor Nanostructures for Sensing, Photocatalysis and Photovoltaics

Karthik Shankar

Conference/Symposium/Workshop Contribution

Sunlight-driven water-splitting using two dimensional carbon based semiconductors

Karthik Shankar, Pawan Kumar

Scholarly Refereed Journal

Surface second harmonic generation spectra of titania coated Au NPs

Karthik Shankar, Ehsan Vahidzadeh

Scholarly Refereed Journal

Synthesis, characterization, and visible light photocatalytic activity of solution-processed free-standing 2D Bi2O2Se nanosheets

Karthik Shankar, Kazi Alam, Saralyn Riddell, Damini Vrushabendrakumar, Harshitha Rajashekhar

Scholarly Refereed Journal

Techno-economic assessment of titanium dioxide nanorod-based perovskite solar cells: from lab-scale to large-scale manufacturing

Amit Kumar, Karthik Shankar, Ujwal Thakur, Eskinder Gemechu, Harshadeep Kukkikatte Ramamurthy Rao

Scholarly Refereed Journal

The life cycle energy and environmental footprints of high-performance monocrystalline titanium dioxide nanorod-base perovskite solar cells

Amit Kumar, Karthik Shankar, Ujwal Thakur, Eskinder Gemechu

Other Event

TiO 2-HfN Radial Nano-Heterojunction: A Hot Carrier Photoanode for Sunlight-Driven Water-Splitting

Karthik Shankar, Ryan Kisslinger, Pawan Kumar, Ehsan Vahidzadeh, Sheng Zeng, Saralyn Riddell, Triratna Parmeshwar Muneshwar

Scholarly Refereed Journal

TiO2 Nanotube - Noble Metal Nanoparticle Heterojunction Photocatalysts for CO2 Reduction

Karthik Shankar, Natalia Semagina, Jing Shen, Ehsan Vahidzadeh, Piyush Kar, Yun Zhang

Conference/Symposium/Workshop Contribution

TiO2 nanotube and nanorod arrays: Playgrounds to study unusual heterojunctions, hot electron phenomena and nanophotonic effects

Karthik Shankar

Conference/Symposium/Workshop Contribution

Top-Down Approaches Towards Single Crystal Perovskite Solar Cells

Karthik Shankar

Scholarly Refereed Journal

Triplet excitons: improving exciton diffusion length for enhanced organic photovoltaics

Karthik Shankar, Bruno Luppi, Manisha Gupta

Scholarly Refereed Journal

UARE Summer Student from India

Aakash Patidar

Visiting Researcher (incoming)

Ultrafast Carrier Dynamics of CdS Nanowires Wrapped In C3N5 Nanosheets

Karthik Shankar, Kazi Alam, Frank Hegmann, Charles Jensen, David Purschke

Conference/Symposium/Workshop Contribution

Unusual Surface Ligand Doping-Induced p-Type Quantum Dot Solids and Their Application in Solar Cells

Karthik Shankar, Hongbo Zeng, Ujwal Thakur

Scholarly Refereed Journal

Use of Periodic Pulses and Non-Native Substrates to Form Nanoporous Metal Oxide Films By Anodization

Karthik Shankar, Ryan Kisslinger

Conference/Symposium/Workshop Contribution

Using 1D and 2D Nanomaterials in Halide Perovskite Solar Cells to Enhance Light Harvesting and Charge Collection

Ujwal Thakur

Doctoral Thesis/Dissertation

Vapor Deposition of Semiconducting P Allotropes into TiO2 Nanotube Arrays for Photo-Electrocatalytic Water Splitting

Karthik Shankar, Ryan Kisslinger, Pawan Kumar, Sheng Zeng, Piyush Kar

Scholarly Refereed Journal

Vapor growth of binary and ternary phosphorus-based semiconductors into TiO2 nanotube arrays and application in visible light driven water splitting

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Pawan Kumar, Piyush Kar

Scholarly Refereed Journal

Visible Light Driven Photocatalysts Based on New Graphenic Semiconductors and Their Heterojunctions

Karthik Shankar, Pawan Kumar, Kazi Alam

Conference/Symposium/Workshop Contribution

Visible Light Responsive, Earth-Abundant Heterojunction Photocatalysts

Karthik Shankar

Conference/Symposium/Workshop Contribution

Water-splitting photoelectrodes consisting of heterojunctions of carbon nitride with a p-type low bandgap double perovskite oxide

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Kazi Alam, Devika Laishram

Scholarly Refereed Journal