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2018-01-01

Karmakar, A., Askar, A.M., Bernard, G.M., Terskikh, V.V., Ha, M., Patel, S., Shankar, K., Michaelis, V.K.

Mixed-halide lead perovskite (MHP) materials are rapidly advancing as next-generation high-efficiency perovskite solar cells due to enhanced stability and bandgap tunability. In this work, we demonstrate the ability to readily and stoichiometrically tune the halide composition in...

2017-01-01

Bernard, G.M., Goyal, A., Miskolzie, M., McKay, R., Wu, Q., Wasylishen, R.E., Michaelis, V.K.

A new solid-state nuclear magnetic resonance (NMR) thermometry sample is proposed. The 207Pb NMR chemical shift of a lead halide perovskite, methylammonium lead chloride (MAPbCl3) is very sensitive to temperature, 0.905 ± 0.010 ppm K−1. The response to temperature is linear over a wide...

2017-01-01

Askar, A.,, Bernard, G.M, Wiltshire,, B., Shankar, K., Michaelis, V.K.

An NMR investigation of methylammonium lead iodide, the leading member of the hybrid organic-inorganic perovskite class of materials, and of its putative decomposition products as a result of exposure to heat and humidity, has been undertaken. We show that the 207Pb NMR spectra of the compound of...

2020-01-01

Ha, M., Karmakar, A., Bernard, G.M., Basilio, E., Krishnamurthy, A., Askar, A.M., Shankar, K., Kroeker, S., Michaelis, V.K.

Hybrid organic–inorganic metal-halide perovskite materials are an emerging class of materials that could profoundly change the optoelectronic and solar absorber research fields and have far-reaching applications. Unfortunately, the leading solar-absorbing candidates are lead-containing materials...

2019-01-01

Thiessen, A.N., Ha, M., Hooper, R.W., Yu, H., Oliynyk, A.O., Veinot, J.G.C., Michaelis, V.K.

Silicon nanoparticles (SiNPs) are biologically compatible, metal-free quantum dots that exhibit size and surface tailorable photoluminescence. The nanostructure of these materials influences their optical, chemical, and material properties and hence plays an important role in their...

2020-01-01

Karmakar, A., Bernard, G.M., Meldrum, A., Oliynyk, A.O., Michaelis, V.K.

Efficient white-light-emitting single-material sources are ideal for sustainable lighting applications. Though layered hybrid lead–halide perovskite materials have demonstrated attractive broad-band white-light emission properties, they pose a serious long-term environmental and health risk as...

2017-01-01

Zhou, B., Faucher, A., Laskowski, R., Terskikh, V.V., Kroeker, S., Sun, W., Lin, J., Mi, J-X., Michaelis, V.K., Pan, Y.

A series of well-characterized magnesium borate minerals and synthetic analogues have been studied via ultrahigh-field 25Mg solid-state NMR spectroscopy. Correlations between 25Mg NMR parameters and the local structure at the magnesium site(s) are highlighted and discussed. First-principles...

2018-01-01

Michaelis, V.K., Levin, K., Germanov, Y., Lelong, G., Kroeker, S.

The functional importance of lithium in many types of materials requires reliable methods for studying its local structure and dynamics. Nuclear magnetic resonance (NMR) spectroscopy should be ideal for this purpose but suffers from poor resolution due to intrinsic dipolar broadening. We overcome...