| Alexander Graham Bell Canada Graduate Scholarship | Award | 2020-09-19 | Riley Hooper |
| Goddard Yuk-Tat Lauw and Yau-Chun Lau (Mak) Memorial Graduate Scholarship | Award | 2020-09-20 | Riley Hooper |
| Graduate Fellowship | Award | 2018-12-31 | Abhoy Karmakar |
| President’s Doctoral Prize of Distinction | Award | 2020-05-20 | Michelle Ha |
| Copper-doped double perovskites and uses thereof (USPTO)Patent No.: US 11,479,477 B2
Date of Patent: 2022-10-25
USPTO Application Serial No. 16/909,072
Filed on: 2020-06-23
Abstract: The present application relates to copper-doped double perovskites, for example, copper-doped double perovskites of the formula (I) and to uses thereof, for example as low-bandgap materials such as a semiconducting material in a device. The present application also relates to methods of tuning the bandgap of a Cs.sub.2SbAgZ.sub.6 double perovskite (for example, wherein Z is Cl) comprising doping the double perovskite with copper. Cs.sub.2Sb.sub.1-aAg.sub.1-bCu.sub.2xZ.sub.6 (I) University of Alberta | IP Management | 2022-10-25 | Michaelis, V., Abhoy Karmakar |
| C3N5: A Low Bandgap Semiconductor Containing an Azo-linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent ApplicationsModification of carbon nitride based polymeric 2D materials for tailoring their optical, electronic and chemical properties for various applications has gained significant interest. The present report demonstrates the synthesis of a novel modified carbon nitride framework with a remarkable 3:5 C:N stoichiometry (C3N5) and an electronic bandgap of 1.76 eV, by thermal deammoniation of melem hydrazine precursor. Characterization revealed that in C3N5 polymer, two s-heptazine units are bridged together with azo linkage, which constitutes an entirely new and different bonding fashion from g-C3N4 where three heptazine units are linked together with tertiary nitrogen. Extended conjugation due to overlap of azo nitrogens and increased electron density on heptazine nucleus due to the aromatic π network of heptazine units lead to an upward shift of the valence band maximum resulting in bandgap reduction down to 1.76 eV. XRD, He-ion imaging, HR-TEM, EELS, PL, fluorescence life time imaging, Raman, FTIR, TGA, KPFM etc clearly show that the properties of C3N5 are distinct from pristine carbon nitride (g-C3N4). When used as an electron transport layer (ETL) in MAPbBr3 based halide perovskite solar cells, C3N5 outperformed g-C3N4, in particular generating an open circuit photovoltage as high as 1.3 V, while C3N5 blended with MAxFA1-xPb(I0.85Br0.15)3 perovskite active layer achieved a photoconversion efficiency (PCE) up to 16.7 %. C3N5 was also shown to be an effective visible light sensitizer for TiO2 photoanodes in photoelectrochemical water splitting. Due to its electron- rich character, the C3N5 material displayed instantaneous adsorption of methylene blue from aqueous solution reaching complete equilibrium within 10 min, which is significantly faster than pristine g-C3N4 and other carbonbased materials. C3N5 coupled with plasmonic silver nanocubes promotes plasmon-exciton coinduced surface catalytic reactions reaching completion at much low laser intensity (1.0 mW) than g-C3N4 which showed sluggish performance even at high laser power (10.0 mW). The relatively
narrow bandgap and 2D structure of C3N5 make it an interesting air-stable and temperature resistant semiconductor for optoelectronic applications while its electron- rich character and intrasheet cavity make it an attractive supramolecular adsorbent for environmental applications. University of Alberta | Publication | 2019-02-14 | Pawan Kumar, Ehsan Vahidzadeh, Ujwal Thakur, Piyush Kar, Kazi Alam, Ankur Goswami, Najia Mahdi, "Kai Cui", Guy Bernard, Michaelis, V., Karthik Shankar |
| Composition-Tunable Formamidinium Lead Mixed Halide Perovskites via Solvent-Free Mechanochemical Synthesis: Decoding the Pb Environments Using Solid-State NMR SpectroscopyMixed-halide lead perovskites are becoming of paramount interest in the optoelectronic and photovoltaic research fields, offering band gap tunability, improved efficiency, and enhanced stability compared to their single halide counterparts. Formamidinium-based mixed halide perovskites (FA-MHPs) are critical to obtaining optimum solar cell performance. Here, we report a solvent-free mechanochemical synthesis (MCS) method to prepare FA-MHPs, starting with their parent compounds (FAPbX3; X = Cl, Br, I), achieving compositions not previously accessible through the solvent synthesis (SS) technique. By probing local Pb environments in MCS FA-MHPs using solid-state nuclear magnetic resonance spectroscopy, along with powder X-ray diffraction for long-range crystallinity and reflectance measurements to determine the optical band gap, we show that MCS FA-MHPs form atomic-level solid solutions between Cl/Br and Br/I MHPs. Our results pave the way for advanced methods in atomic-level structural understanding while offering a one-pot synthetic approach to prepare MHPs with superior control of stoichiometry. University of Alberta | Publication | 2018-05-01 | Abdelrahman M Askar, Abhoy Karmakar, Guy Bernard, Michelle Ha, Victor V Terskikh, Benjamin Wiltshire, Sahil Patel, Jonathan Fleet, Karthik Shankar, Michaelis, V. |
| Influence of hidden halogen mobility on local structure of CsSn(Cl1-xBrx)3 mixed-halide perovskites by solid-state NMR University of Alberta | Publication | 2021-01-01 | Abhoy Karmakar, Amit Bhattacharya, Diganta Sarkar, Guy Bernard, Mar, A., Michaelis, V. |
| Lead-207 NMR Spectroscopy at 1.4 T: Application of Benchtop Instrumentation to a Challenging I = \textonehalf Nucleus University of Alberta | Publication | 2020-05-01 | Guy Bernard, Michaelis, V. |
| Mechanochemical synthesis of 0D and 3D cesium lead mixed halide perovskites University of Alberta | Publication | 2019-04-03 | Abhoy Karmakar, Mya S Dodd, Xiaoyue Zhang, Meagan S Oakley, Mariusz Klobukowski, Michaelis, V. |
| Phase Evolution in Methylammonium Tin Halide Perovskites with Variable Temperature Solid-State 119Sn NMR Spectroscopy University of Alberta | Publication | 2020-07-01 | Michelle Ha, Abhoy Karmakar, Guy Bernard, Enoc Basilio, Arun Krishnamurthy, Abdelrahman M Askar, Karthik Shankar, Scott Kroeker, Michaelis, V. |
| Tailorable Indirect to Direct Band-Gap Double Perovskites with Bright White-Light Emission: Decoding Chemical Structure Using Solid-State NMR University of Alberta | Publication | 2020-05-01 | Abhoy Karmakar, Guy Bernard, Al Meldrum, Anton Oliynyk, Michaelis, V. |
| “Turning the dials”: controlling synthesis, structure, composition, and surface chemistry to tailor silicon nanoparticle properties University of Alberta | Publication | 2021-01-01 | Sarah Milliken, Alyx Thiessen, I Teng Cheong, Kevin O'Connor, Ziqi Li, Riley Hooper, Christopher Robidillo, Veinot, J. |
