DiaDEM Tutorial: Discovery of Near-Infrared Materials

The discovery of near-infrared materials can be achieved with the DiaDEM platform. Candidates can be purchased directly and tested for near-infrared activity by the researcher.

General theory

Near-infrared materials are a class of compounds that can absorb and emit light in the near-infrared range (750-2500 nm). Their applications span a wide variety of domains including communications, medical imaging, photovoltaics, sensing and night-vision. The synthesis of photostable, high-mobility and device-compatible near-infrared compounds is extremely challenging, making them a rare and coveted class of materials. Near-infrared absorption and emission in organic compounds is normally seen in extended π-conjugated systems, donor-acceptors, ionic dyes and metal complexes.

Requirements for near-infrared absorption-emission

The requirement for near-infrared absorption-emission is simply the existence of near-infrared absorption and/or emission band(s) in the respective absorption and fluorescence spectra. In computational terms, the energy of the \(S_{0}\) \(\rightarrow\) \(S_{1}\) transition E(\(S_{1}\)) should be lower than 1.65 eV (750 nm). Due to molecular design, these low-energy states are usually weak in intensity, e.g. small transition dipole moment for donor-acceptors due to non-spatially-overlapping HOMO and LUMO; therefore, a bright \(S_{1}\) can be imposed by setting a lower limit for the oscillator strength f(\(S_{1}\)).

Searching for candidates

Finding near-infrared candidates based on the requirements detailed above can be done using the Search functionality found on the navigation bar. First click +Group, then +Rule twice. Choose the Property Name for the first singlet excited state transition energy E(\(S_{1}\)) and set the Value to be less than 1.65 eV, then Submit Query.

This will search the DiaDEM database for all molecules which have an experimentally calibrated, vertical \(S_{0}\) \(\rightarrow\) \(S_{1}\) energy lower than the boundary of red to near-infrared light. For additional constraints, return to the Search function and add another condition block within the same query using +Group. Continue by choosing the oscillator strength for the first singlet transition f(\(S_{1}\)) and set this Value to be greater than 0.05. This value can be modified; the greater the value, the brighter the \(S_{1}\) state is predicted to be, removing those entries with forbidden or low-intensity transitions.

Purchasing materials

All of the molecules on the DiaDEM database are commercially available and can be purchased directly for laboratory testing; however, availability for a material at any given time can vary.

In the Search results, clicking on a molecular entry will open a new page with greater detail, including more properties, availability and price. You can add a material to cart by clicking Add to cart. The cart can be accessed at the top right of the banner. From here, the quantity of material can be modified. An Indicative price will be shown and a purchase request can be made by pressing Submit request. After processing, final pricing, delivery time and additional information will be provided, and a Notification will appear which can be opened from the navigation bar. If email notifications are enabled, an automated email will be sent.