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.

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

Karthik Shankar, Ujwal Thakur, Pawan Kumar, Ehsan Vahidzadeh

Conference/Workshop

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

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur, Saralyn Riddell

Conference/Workshop

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

Karthik Shankar, Ujwal Thakur

Conference/Workshop

Application of TiO2 Nanotubes and Nanowires in Photocatalytic CO2 Reduction

Karthik Shankar, Ujwal Thakur, Piyush Kar

Conference/Workshop

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

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

Conference/Workshop

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

Karthik Shankar

Conference/Workshop

CO2 photoreduction using earth abundant transition metal oxides & chalcogenides

Karthik Shankar

Conference/Workshop

CO2 reduction performance of TiO2 nanotube-based heterojunction photocatalysts

Karthik Shankar, Ehsan Vahidzadeh, Piyush Kar

Conference/Workshop

Chalcogenide Semiconductor Nanomaterials for Photocatalytic Applications

Karthik Shankar, Ujwal Thakur, Piyush Kar

Conference/Workshop

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

Karthik Shankar

Conference/Workshop

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

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

Conference/Workshop

Copper Sulfide Nanostructures and their utility in Photocatalytic CO2 Reduction

Karthik Shankar, Piyush Kar, Yun Zhang

Conference/Workshop

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/Workshop

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

Karthik Shankar

Conference/Workshop

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/Workshop

Enhancing Photocatalyst and Solar Cell Performance Using Nanophotonic Effects

Karthik Shankar, Ujwal Thakur, Sheng Zeng, Piyush Kar

Conference/Workshop

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

Karthik Shankar, Ehsan Vahidzadeh, Sheng Zeng, Ajay Manuel

Conference/Workshop

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

Karthik Shankar, Kazi Alam

Conference/Workshop

Helped organize the 2D Materials symposium at ICEE'2020

Karthik Shankar

Conference/Workshop

High Selectivity CO2 Photoreduction Using Earth Abundant Semiconductor Photocatalysts

Karthik Shankar, Ryan Kisslinger, Ehsan Vahidzadeh, Sheng Zeng

Conference/Workshop

High Voc halide perovskite solar cells using optimized charge transport layers

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

Conference/Workshop

Highly Structured Nanomaterials for High Performance Photocatalysts and Solar Cells

Karthik Shankar

Conference/Workshop

MITACS Globalink Summer Intern from Germany

Timotheus Hohl

Visiting Student (incoming)

MITACS Globalink Summer Intern from India

Priyash Barya

Visiting Student (incoming)

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

Karthik Shankar, Ryan Kisslinger, Pawan Kumar, Sheng Zeng

Conference/Workshop

Novel Materials for Clean and Sustainable Energy CHALLENGE PROGRAM WORKSHOP

Karthik Shankar

Conference/Workshop

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/Workshop

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/Workshop

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

Karthik Shankar

Conference/Workshop

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

Karthik Shankar, Sheng Zeng

Conference/Workshop

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

Karthik Shankar, Ryan Kisslinger, Ujwal Thakur

Conference/Workshop

Robust Plasmonic Glasses using nanoporous TiO2 embedded with Au nanoparticles

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

Conference/Workshop

SERB Overseas Visiting Doctoral Fellowship

Sachin Kadian

Visiting Student (incoming)

SERC Overseas Visiting Doctoral Fellowship

Devika Laishram

Visiting Student (incoming)

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

Karthik Shankar

Conference/Workshop

TiO2 Nanotube - Noble Metal Nanoparticle Heterojunction Photocatalysts for CO2 Reduction

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

Conference/Workshop

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

Karthik Shankar

Conference/Workshop

UARE Summer Student from India

Aakash Patidar

Visiting Student (incoming)

Ultrafast Carrier Dynamics of CdS Nanowires Wrapped In C3N5 Nanosheets

Karthik Shankar, Frank Hegmann, Charles Jensen, David Purschke

Conference/Workshop

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

Karthik Shankar, Ryan Kisslinger

Conference/Workshop

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

Karthik Shankar, Pawan Kumar, Kazi Alam

Conference/Workshop

Visible Light Responsive, Earth-Abundant Heterojunction Photocatalysts

Karthik Shankar

Conference/Workshop

Alberta Graduate Excellence Scholarship

Sheng Zeng

Award

Alberta Graduate Excellence Scholarship

Sheng Zeng

Award

Alberta Innovates Graduate Scholarship

Ujwal Thakur

Award

Alberta Innovates Graduate Student Scholarship

Ryan Kisslinger

Award

Doctoral Recruiting Scholarship

Damini Vrushabendrakumar

Award

Doctoral Recruiting Scholarship

Harshitha Rajashekhar

Award

Doctoral Recruiting Scholarship

Navneet Kumar

Award

E-MRS 2019 Best Poster Award (Symposium N)

Ryan Kisslinger

Award

FGSR Doctoral Prize of Distinction

Ajay Manuel

Award

Faculty of Engineering NSERC Scholarship Supplementary Award

Ryan Kisslinger

Award

Graduate Recruitment Scholarship

Md Rana

Award

MITACS Globalink Research Award

Ehsan Vahidzadeh

Award

NSERC CGSD Scholarship

Ryan Kisslinger

Award

NSERC CGSD Scholarship

Ajay Manuel

Award

NSERC Undergraduate Student Research Award (USRA)

Xinkai Xu

Award

NSERC Undergraduate Student Research Award (USRA)

Dipesh Aggarwal

Award

NSERC Undergraduate Student Research Award (USRA)

Catlin Letendre

Award

NSERC Undergraduate Student Research Award (USRA)

Phillip Kirwin

Award

NSERC Undergraduate Student Research Award (USRA)

Collin VanEssen

Award

NSERC Undergraduate Student Research Award (USRA)

Darren Dahunsi

Award

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) 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

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

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

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 Michaelis, Ankur Goswami, Guy Bernard

Scholarly Refereed Journal

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

Characterization of Carrier Dynamics in Metal Oxide Nanostructures and Tellurophenes

Benjamin Wiltshire

Masters Thesis

Collaborative Ultrafast Spectroscopic Laser (CUSL) facility

Karthik Shankar, Al Meldrum, Juli Gibbs, Frank Hegmann

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

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

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

Karthik Shankar, Najia Mahdi, Piyush Kar

Scholarly Refereed Journal

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

Double peak emission in lead halide perovskites by self-absorption

Karthik Shankar

Scholarly Refereed Journal

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

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

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

Karthik Shankar, Ujwal Thakur, Pawan Kumar

Scholarly Refereed Journal

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

Karthik Shankar

Invited/Keynote

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

Karthik Shankar

Invited/Keynote

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

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

Karthik Shankar

Invited/Keynote

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

Karthik Shankar, Ajay Manuel

Scholarly Refereed Journal

Introduction to plasmonics and the MEMS application of surface plasmons

Karthik Shankar

Invited/Keynote

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

Karthik Shankar

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

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

Invited/Keynote

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 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

PhD Thesis

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 Properties of Anatase and Rutile Phase TiO2 Nanotubes

Yun Zhang

Masters Thesis

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

Karthik Shankar, Vladimir 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 Michaelis, Charles Jensen, Guy Bernard, David Purschke, Riley Hooper, Narendra Chaulagain

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

PhD Thesis

Plasmonic Catalysis: Fundamentals, Materials, Methods And Challenges

Karthik Shankar

Invited/Keynote

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

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

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

Karthik Shankar, Pawan Kumar

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

Triplet excitons: improving exciton diffusion length for enhanced organic photovoltaics

Karthik Shankar, Bruno Luppi, Manisha Gupta

Scholarly Refereed Journal

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

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

Ujwal Thakur

PhD Thesis

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

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