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This Energy Focus article summarizes the topics presented at the Nanomaterials and Sustainability Workshop held on May 4th, 2023 as part of the annual Advanced Photon Source/Center for Nanoscale Materials Users Meeting. Nanomaterials with novel properties and phenomena offer tremendous opportunities for sustainable technologies that address critical environmental and energy applications. The large variation that is possible for nanomaterials across composition, dimension, size and geometry aids in the range of properties and applications that can conceivably be addressed. However, in order to have maximum impact, earth abundance of materials must be considered and scalable manufacturing technologies must be developed. The opportunities discussed at the workshop are organized into topical areas of Nanostructured Materials for Sustainable Energy Solutions; Nano-bio Hybrid Materials for Energy and CO2 Reduction; and Sustainable Manufacturing at the Nanoscale. 

The design/synthesis and characterization of organic donor–acceptor (D–A) dyads can provide precious data allowing to improve the efficiency of classical photo-induced bimolecular interactions/processes. In this report, two novel triplet D–A dyads (4 and 5) were synthesized and fully characterized. While the optical absorption and emission profiles of these new systems exhibit similar spectral structures as that of the triplet donor/sensitizer quinoidal thioamide (QDN), the transient absorption (TA) spectra of these two dyads produced new features that can be associated with triplet transients and charge transfer species. However, the kinetics of the excited-state processes/dynamics is significantly influenced by the geometrical arrangement(s) of donor/acceptor chromophores. Further analysis of the TA data suggests that the dyad with slip-stack geometry (4) is less effective in undergoing both intra- and inter-dyad triplet energy transfer than the dyad with co-facial geometry (5). Subsequently, triplet sensitization of 9,10-diphenylanthracene (DPA) using both dyads led to upconverted photoluminescence via triplet–triplet annihilation of DPA triplet transients. But, it was found that a maximum upconversion quantum yield could be achieved at a low power density using the co-facial type dyad 5. Altogether, these results provide valuable guidance in the design of triplet donor–acceptor dyads, which could be used for light-harvesting/modulation applications.