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Purely organic materials usually exhibit weak spin–orbital coupling (SOC) effect because of the lack of noble heavy metals, and the generation and direct emission from the triplet state is spin-forbidden. This would lead to slow intersystem crossing, long triplet lifetime, and low phosphorescence quantum yield. Herein, strong spin–orbital coupling between singlet and triplet was observed in a “flexible” and twist thianthrene-pyrimidine-based purely organic compound in an amorphous film state, which shows a fast intersystem crossing process and a high phosphorescence rate of 1.1 × 103 s–1. The heavy atom sulfur and nitrogen atoms in the molecule can provide n−π* transition character for efficient spin–orbital coupling. Moreover, the flexible molecule skeleton enables conformational change and molecular vibration in excited states, which was proved to be vital for efficient vibrational spin–orbital coupling. Benefitting from the strong SOC effect, a nondoped purely organic phosphorescence light-emitting diode was fabricated, which achieves a maximum external quantum efficiency of 7.98%, corresponding to an exciton utilization ratio exceeding 87.6%.

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The beryllium doped small-sized magnesium and their ions clusters are fully studied in this work. CALMPSO software was used to search for BeMgnQ (Q=0, ±1, n = 2 - 12)...

Harvesting high-energy excited-state energy is still challenging in organic chromophores. An introduction of boron atoms along the short axis of the diazapentacene backbone induces multiple emission characteristics. Our studies reveal that the weak molecular orbital (MO) coupling of the S 3 −S 1 transition is responsible for the slow internal conversion rates. Such MO coupling-regulated anti-Kasha emission is different from the large band gap-induced anti-Kasha emission character of classical azulene derivatives. Theoretical studies reveal that a strong MO coupling of the S 3 −S 0 transition is responsible for the higher photoluminescence quantum yield of the anti-Kasha emission in a more polar solution (tetrahydrofuran: 11%; cyclohexane: 0%). Such an MO coupling factor is generally overlooked in anti-Kasha emitters reported previously. Furthermore, the multiple emission can be regulated by solvent polarity, solvent temperature, and fluoride anion binding. As a proof of concept of harvesting high-energy emission, the multiple emission character has allowed us to design single-molecule white-light-emitting materials.

Several potential stable structures of X-doped magnesium (X = Ge, C, Sn) clusters have been fully investigated by using CALYPSO structure searching software together with density functional theory calculations. XMg n (X = Ge, C, Sn; n = 3–7) clusters have similar geometric structure grows in tetrahedron, while the structures of XMg n (X = Ge, C, Sn; n = 8–12) are based on a kind of tower-like geometry. Interestingly, the relative stability computations indicate that XMg8 (X = Ge, C, Sn) are more stable than other clusters, and thus can be identified as magic clusters. In addition, XMg8's (X = Ge, C, Sn) high stability and atomic interactions contained in structures are studied through their electronic localization function and molecular orbitals. It is shown that the covalent σ bond interaction of X–Mg and Mg–Mg are mainly responsible for their robust stability. Finally, the theoretical calculations of IR and Raman spectra of XMg8 (X = Ge, C, Sn) clusters were implemented for guiding further experimental observation.

A recyclable photoelectrode with high degradation capability for organic pollutants is crucial for environmental protection and, in this work, a novel CeO2 quantum dot (QDs)/Ag2Se Z-scheme photoelectrode boasting increased visible light absorption and fast separation and transfer of photo-induced carriers is prepared and demonstrated. A higher voltage increases the photocurrent and 95.8% of tetracycline (TC) is degraded by 10% CeO2 QDs/Ag2Se in 75 minutes. The degradation rate is superior to that achieved by photocatalysis (92.3% of TC in 90 min) or electrocatalysis (27.7% of TC in 90 min). Oxygen vacancies on the CeO2 QDs advance the separation and transfer of photogenerated carriers at the interfacial region. Free radical capture tests demonstrate that •O2−, •OH, and h+ are the principal active substances and, by also considering the bandgaps of CeO2 QDs and Ag2Se, the photocatalytic mechanism of CeO2 QDs/Ag2Se abides by the Z-scheme rather than the traditional heterojunction scheme. A small amount of metallic Ag formed in the photocatalysis process can form a high-speed charge transfer nano channel, which can greatly inhibit the photogenerated carrier recombination, improve the photocatalytic performance, and help form a steady Z-scheme photocatalysis system. This study would lay a foundation for the design of a Z-scheme solar photocatalytic system.