A long-standing challenge in photoinduced electron transfer research is the design of compact donor−acceptor dyads that can generate long-lived charge-separated (CS) states for use as sensitizers in solar energy harvesting. Reports of dyads exhibiting CS state lifetimes in the microsecond time domain are very rare. Herein, we report two compact donor−bridge−acceptor dyads exhibiting lifetimes in the microsecond domain. We employed an adamantane moiety as a bridge, and the lifetimes obtained are nearly 1000-fold larger when compared to those of the same donor−acceptor dyads bridged through C 3 -alkyl chains. In addition to long-lived CS state decays, slow formation of acceptor triplets was also observed via nanosecond flash photolysis. The long lifetime of the CS state is attributed to the extremely small value of the electronic coupling matrix element for the charge recombination compared to charge separation. P hotogenerated radical-ion pairs (RP) in linked donor− acceptor (D−A) dyads are extremely short-lived because of the very fast charge recombination (CR) reaction either to the D−A ground state or to a low-lying local triplet ( 3 D* or 3
Herein we report a very facile, bottom‐up synthesis of macrographene sheets of up to 1–2 μm size, in two steps from readily available starting materials under mild reaction conditions. The synthesis involved the reduction of 4,4’‐biphenylene bisdiazonium salt in aqueous solution at room temperature using methanolic sodium borohydride. The reduction reaction results in the formation of 4,4’‐biphenylele biradicals which underwent rapid addition reactions to give a cross‐linked polycyclic aromatic hydrocarbon frame work. Scholl oxidation of the aromatic frame work gave macrographene sheets in good yields in gram quantities. Formation of the graphene sheets was confirmed by several technique including X‐ray photoelectron spectroscopy, Raman spectroscopy, TEM and AFM analysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.