Muhammad Umair Hassan

Negative differential transconductance in electrolyte-gated ruthenate

We report on a study of electric field-induced doping of the highly conductive ruthenate SrRuO3 using an ionic liquid as the gate dielectric in a field-effect transistor configuration. Two distinct carrier transport regimes are identified for increasing positive gate voltage in thin (10 nm) films grown heteroepitaxially on SrTiO3 substrates. For Vg = 2 V and lower, the sample shows an increased conductivity of up to 13%, as might be expected for electron doping of a metal. At higher Vg = 2.5 V, we observe a large decrease in electrical conductivity of >20% (at 4.2 K) due to the prevalence of strongly blocked conduction pathways.

Contact Lenses for Color Blindness

Abstract Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545–575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management.