Selective formation of multicomponent structures via the self-assembly of numerous building blocks is ubiquitous in biological systems but challenging to emulate synthetically. More components introduce additional possibilities for kinetic intermediates with trap-state ability, hampering access to desired products. In covalent chemistry, templates, reagents and catalysts are applied to create alternative pathways for desired product formation. Analogously, we enlist exo-templating to mould the formation of large, multicomponent supramolecular structures. Specifically, a charged ring docks at 1,5-dioxynaphthalene stations within exo-functionalized building blocks to promote formation of cuboctahedral Pd12L24 nanospheres via exoskeletal templating. With the exo-templating ring present, nanosphere formation occurs via small Pdx–Ly oligomers, while in the absence of the ring a Pdx–Ly polymer resting state rapidly evolves, from which nanosphere formation occurs slowly. We demonstrate a form of kinetic templating—via intermediate destabilization—resembling properties observed in catalysis. Importantly, unlike typically employed endo-templates, we demonstrate that exo-templating is particularly suited for larger, complex, self-assembled structures.

In this section, we described the various device architectures in production for crystalline-silicon PV as well as the various absorber materials being used and developed for thin-film PV. We also explained why multijunction PV technology is considered the future of PV technology. We identified four major technological challenges (Fig. 1) for future mass production and deployment of PV technology in order to achieve the goal of climate neutrality and indicated how optics could help resolve these challenges. The four main challenges (Fig. 1) are: • Sustainable production of PV systems; • Higher energy conversion efficiencies; • Higher energy output and operational lifetime; • Integration of PV systems in their environment.

Solar-powered electrochemical production of hydrogen through water electrolysis is an active and important research endeavor. However, technologies and roadmaps for implementation of this process do not exist. In this perspective paper, we describe potential pathways for solar-hydrogen technologies into the marketplace in the form of photoelectrochemical or photovoltaic-driven electrolysis devices and systems. We detail technical approaches for device and system architectures, economic drivers, societal perceptions, political impacts, technological challenges, and research opportunities. Implementation scenarios are broken down into short-term and long-term markets, and a specific technology roadmap is defined. In the short term, the only plausible economical option will be photovoltaic-driven electrolysis systems for niche applications. In the long term, electrochemical solar-hydrogen technologies could be deployed more broadly in energy markets but will require advances in the technology, significant cost reductions, and/or policy changes. Ultimately, a transition to a society that significantly relies on solar-hydrogen technologies will benefit from continued creativity and influence from the scientific community.