A direct comparison of a next generation hyperspectral camera to state-of-the-art.

Hyperspectral camera technology is advancing rapidly, and this paper seeks to compare a state-of-the-art industrial dual-camera setup to a single-camera system employing the latest chip technology (IMX990 from Sony). The hyperspectral cameras are compared over both the Visual and Short-Wave Infrared range (400-1700 nm) of the electromagnet spectrum. The spectral range and resolution, as well as spatial parameters and spectroscopic information are quantified with comparable optics, electronics, and test targets. Generally, enhanced spectral detail and reduced noise were observed for the single-camera compared to its peers. Thus, the IMX990 shows promising performance for the new generation of hyperspectral cameras directly relevant to industrial applications, such as detection, documentation, and sorting.

Controlled electrochemical carboxylation of graphene to create a versatile chemical platform for further functionalization.

An electrochemical approach is introduced for the versatile carboxylation of multi-layered graphene in 0.1 M Bu4NBF4/MeCN. First, the graphene substrate (i.e., graphene chemically vapor-deposited on Ni) is negatively charged at -1.9 V versus Ag/AgI in a degassed solution to allow for intercalation of Bu4N(+) and, thereby, separation of the individual graphene sheets. In the next step, the strongly activated and nucleophilic graphene is allowed to react with added carbon dioxide in an addition reaction, introducing carboxylate groups stabilized by Bu4N(+) already present. This procedure may be carried out repetitively to further enhance the carboxylation degree under controlled conditions. Encouragingly, the same degree of control is even attainable, if the intercalation and carboxylation is carried out simultaneously in a one-step procedure, consisting of simply electrolyzing in a CO2-saturated solution at the graphene electrode for a given time. The same functionalization degree is obtained for all multi-layered regions, independent of the number of graphene sheets, which is due to the fact that the entire graphene structure is opened in response to the intercalation of Bu4N(+). Hence, this electrochemical method offers a versatile procedure to make all graphene sheets in a multi-layered but expanded structure accessible for functionalization. On a more general level, this approach will provide a versatile way of forming new hybrid materials based on intimate bond coupling to graphene via carboxylate groups.