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Thermally activated delayed fluorescence (TADF) has been widely applied to electroluminescent materials to take the best advantage of triplet excitons. For some materials, the TADF originates from high-level reverse intersystem crossing (hRISC), and has attracted much attention due to its high efficiency for utilizing the triplet excitons. However, reports concerning the mechanistic studies on the hRISC-TADF process and structure–property correlation are sparse. In this study, we prepared three compounds containing triphenylamine and benzophenone with different substitution positions, o-TPA-BP, m-TPA-BP, and p-TPA-BP, in which only p-TPA-BP displays strong luminescence and hRISC-TADF features. To investigate the mechanism of the substituent-position-dependent hRISC-TADF, ultrafast time-resolved spectroscopy was utilized to observe the deactivation pathways with the assistance of theoretical calculations. The results show that o-TPA-BP will not generate triplet species, and the triplet species for m-TPA-BP will rapidly deactivate. Only p-TPA-BP can transition back to the singlet state from the T2 state effectively and exhibit a large gap between T1 and T2 to favor the hRISC route. These results illustrate how the substitution position affects the ISC and further influences the luminescence properties, which can provide new insights for developing new high-efficiency luminescent materials. [ABSTRACT FROM AUTHOR]

This research article uses density functional theory (DFT) to study photoinduced borylation. This work examined the electron donor‐acceptor complex (EDA) of bis(catecholato)diboron with different redox‐active leaving groups and bis(pinacol)diboron with aryl N‐hydroxyphthalimide. The results of these DFT studies show the complex ratio of B2cat2 and N, N‐dimethylacetamide (DMA) should be 1 : 2 which is consistent with the experimental results in the literature. We further proposed a reaction mechanism and calculated the energies associated with each step. [ABSTRACT FROM AUTHOR]

In this review, noncovalent functionalization of single-wall carbon nanotubes (SWCNTs) is briefly reviewed. The functional materials summarized here include metalloporphyrin derivatives, biomolecules and conjugated polymers. Notably, time-resolved spectroscopic techniques such as time-resolved fluorescence and transient absorption were employed to directly investigate the electron transfer and recombination processes between the functionalities and the SWCNTs. In addition, Raman spectroscopy is also useful to identify the interaction and the electron transfer direction between both the functionalities and the SWCNTs. An improved understanding of the mechanisms of these SWCNT-based nanohybrids in terms of their structural and photophysical properties can provide more insights into the design of new electronic materials.

Elemental red phosphorus (red P) is a new class of photocatalysts with a desirable bandgap of ∼1.7 eV and has a strong visible-light response. Here, we show that the efficiency of red P is limited by severe electron trapping at deep traps that are intrinsic to the different crystal facets of the red P. To overcome this, we synthesized the red P/RGO (reduced graphene oxide) composite in a one-step ampoule chemical vapor deposition synthesis that formed a conducive interface between the red P photocatalyst and the RGO acceptor for efficient interfacial charge transport. As substantiated through photoelectrochemical characterization and ultrafast (femtoseconds) transient absorption spectroscopy, the interfacing with RGO provided a rapid pathway for the photocharges in red P to be interfacially separated, thereby circumventing the slower the charge trapping process. As a result, up to a sevenfold increase in the photocatalytic hydrogen production rate (apparent quantum yield = 3.1% at 650 nm) was obtained for the red P/RGO relative to the pristine red P. [ABSTRACT FROM AUTHOR]

Effective utilization of solar energy through cocrystal strategy is still a considerable challenge. Herein, the ternary cocrystal strategy is subtly applied to broaden the absorption of cocrystals, resulting in an efficient solar photothermal conversion (PTC). Specifically, the donors of triphenylene (T) and perylene (P) and guest molecules anthracene (AT), pyrene (PY), and perylene (P) are self‐assembled with 7,7,8,8‐tetracyanoquinodimethane (TCNQ) to obtain five ternary cocrystals (AT‐T‐TCNQ, PY‐T‐T‐TCNQ, AT‐P‐TCNQ, PY‐P‐TCNQ, and P‐P‐TCNQ). The PTC of ternary cocrystals can be regulated by changing the number of benzene rings of donor and guest molecules, which may be attributed to the π–π and C–H···π intermolecular interactions. Femtosecond transient absorption and excited‐state theoretical calculations confirm that the intense π–π stacking interactions facilitate the light‐harvesting capability, while the weak C–H···π interactions are conducive to molecular stacking loosening and thus facilitate the rotation of C(C ≡ N)2, which promotes nonradiative transition to achieve the efficient PTC. As expected, the PTC efficiencies of AT‐T‐TCNQ, PY‐T‐TCNQ, AT‐P‐TCNQ, PY‐P‐TCNQ, and P‐P‐TCNQ are 59.62%, 63.07%, 81.72%, 79.06%, and 87.72%, respectively, under 808 nm irradiation. Due to the P‐P‐TCNQ having excellent near‐infrared PTC efficiency, it is applied in a solar‐driven interfacial heating evaporation system, gaining a decent evaporation efficiency (83.1%). [ABSTRACT FROM AUTHOR]