ChemPhotoChem最新文献

Triplet-triplet annihilation upconversion (TTA-UC) technology could convert low-energy light into high-energy light, and it is a very promising one of the upconversion technologies due to its non-coherent excitation light, low required excitation optical power density and sensitizer/annihilator flexible adjustability. The application of TTA-UC into photocatalysis could not only broaden the range of solar energy spectrum utilization, but also bring mild reaction conditions and higher product yields via avoiding the side reaction. However, the detailed catalytic mechanism of TTA-UC is unclear. Therefore, in this review, we summarized and classified TTA-UC photocatalytic chemical reactions in terms of mechanism.

In an era marked by a growing emphasis on sustainability and innovation, the quest for eco-friendly solutions to energy conversion devices capable of harnessing visible light has gained paramount importance. In response to this critical demand, we demonstrate visible light-responsive photoswitching from molybdenum trioxide nanobelt arrays in the photoconductive device fabricated using solution-processing technique. We exploit the visible light-driven modulation of conductivity in the reversibly switchable photochromic state of MoO₃ to develop a photochromism-assisted photoconductive photodetector with fast response (<0.1 s), significant photocurrent on/off ratio and excellent responsivity (41 AW⁻¹ at 459 nm) under the applied bias of 5 V. The light harvesting strategy presented herein holds the potential for efficient energy generation by harnessing visible light, even under low-light conditions.

This article reports a detailed mechanistic and kinetic study of an unusual photoreaction leading to the (diazonia)tetrabenzonaphthacene skeleton. The photo-triggered double intramolecular nucleophilic aromatic substitution (S_NAr*) has been investigated by varying the leaving groups. Photoreaction quantum yields have been determined and mechanistic insights have been supported by theoretical calculations using DFT and TD-DFT methods. Additionally, we show that this light-triggered formed diazonia constitutes a potent photosentitizer with a singlet oxygen generation quantum yield of 0.55, both in organic solvents and in water, which is an extremely relevant value in view of PDT applications or use as an oxidation photocatalyst in aqueous media. Once again, the experimental observations were supported by TD-DFT calculations showing a large density of triplet states below the S₁ excited state along with large spin-orbit couplings. The reaction is not restricted to solutions but can also occur in solid PDMS matrices thus allowing for photochemical encoding of information that will progressively vanish upon prolonged UV-exposure.

π−π stacking interactions are generally thought to reduce the luminescence of materials. Here, a systematic investigation is conducted using a π−π stacking dimer with varying steric hindrance substituents as a model to illustrate how π−π stacking structure affects the luminescence efficiency of materials. Four naphthalimide (NI) derivative molecules were designed and synthesized by incorporating sterically hindered unilateral groups to achieve NIPH, NIP1C, NIP2C, and NIP3C. It was figured out that side group modification did affect their crystal packing structures and luminescent properties. On the one hand, the excimer state formed by strongly interacted π−π NI-based dimer (NIPH and NIP3C) enhances luminescence efficiency compared to the monomer state based on weakly interacted π−π NI-based dimers (NIP1C and NIP2C). On the other hand, the discrete stacking of NI-based dimers (NIP3C) further promotes luminescence efficiency compared to the nondiscrete stacking of NI-based dimers (NIPH). Among these four compounds, NIP3C exhibits discrete stacking of π−π NI-based dimer due to the large steric hindrance generated by propyl benzene, resulting in the highest luminescence efficiency of the NIP3C crystal. This work will provide further insight into the underlying mechanisms behind the high luminescence efficiency induced by π−π dimer stacking.

This work introduces a novel ternary heterostructure as a photocatalyst to selectively produce benzaldehyde from benzyl alcohol through photooxidation. We have synthesized bismuth vanadate functionalized graphitic carbon nitride decorated reduced graphene oxide B/CN@rGO ternary composite and subsequently subjected it to several characterization methodologies like XRD, FE-SEM, HR-TEM, XPS, FT-IR, TGA, UV-vis DRS, and EIS. The synthesized B/CN@rGO was effectively used in the photooxidation process to produce benzaldehyde from benzyl alcohol, employing a cost-effective white LED light of 200 W. Remarkable selectivity (100 %) towards the benzaldehyde was attained employing green oxidant H₂O₂. In addition, the synthesized photocatalyst showed unique thermal stability and could be reused for over five cycles without compromising the selectivity of the resulting product. Based on our comprehensive review of the existing study, the present work introduces a unique approach for the photooxidation of benzyl alcohol, employing B/CN@rGO ternary heterostructure as the photocatalyst.

In microcavity, strong coupling between light and molecules leads to the formation of hybrid excitations, i. e., the polaritons, or exciton-polaritons. Such coupling may alter the energy landscape of the system and the optical properties of the material, making it an effective approach for controlling the light emission from molecular materials. However, due to the complexity of vibrational modes, spectroscopic calculations for organic exciton-polaritons remain to be challenging. In this work, based on the linear-response quantum-electrodynamical time-dependent density functional theory (QED-TDDFT), we employ the thermal vibrational correlation function (TVCF) formalism to calculate the molecular optical spectrum of the lower polaritons (LP) at first-principles level for three molecules, i. e., anthracene, distyrylbenzenes (DSB), and rubrene. The polaron decoupling effect is confirmed from our first-principles computations. The theoretical emission spectra of LP provide new insights for aiding molecular and device design in microcavities that are otherwise hindered due to the lack of vibrational information.

The Front Cover illustrates ultrafast spectroscopic insights into photoexcited energy relaxation pathways of the cationic green fluorescent protein (GFP) chromophore derivatives in aqueous solution. The electron-withdrawing and electron-donating groups (EWGs and EDGs) notably affect the ring-twisting rates on femtosecond-to-picosecond timescales, whereas excited-state proton transfer (ESPT) to solvent molecules occurs more rapidly in competition. Cover design by Jiawei Liu, Cheng Chen, and Chong Fang. More information can be found in their Research Article (DOI 10.1002/cptc.202400037).

The development of highly efficient deep red materials with emission wavelength beyond 650 nm remains a big challenge due to the constraints imposed by the energy gap rule. In this work, a donor-acceptor-donor type emitter, 4,7-bis (10-(4-(tert-butyl) phenyl)-10H-phenothiazin-3-yl) benzo[c][1,2,5] thiadiazole (TBPPTZ) is designed and synthesized. Resulting from the slight twist angle between the donor and acceptor units, TBPPTZ exhibits nearly planar conformation and an extended conjugated structure. TBPPTZ shows a deep red emission peak at 687 nm and aggregation induced emission property with a high photoluminescence quantum yield of 45 % in neat thin film. The optimized organic light-emitting diode (OLEDs) utilizing TBPPTZ as the non-doped emissive layer obtains a high external quantum efficiency (EQE) up to 2.51 % with an electroluminescence (EL) peak at 676 nm, aligning with the Commission Internationale de L'Eclairage (CIE) coordinates (0.68, 0.31), which shows a small EQE roll-off of only 5.6 % at 100 cd m⁻². Additionally, the doped OLED achieves an EQE up to 5.09 %, with an EL peak at 656 nm and CIE coordinates of (0.65, 0.34). The findings of this research not only contribute to achieve highly efficient deep red OLEDs but also offer a novel and effective deep red molecular strategy to realize high-quality OLEDs.

H₂S and CO₂ are common coexisted gases widely existing in natural gas resources, and they need to be treated harmlessly. The traditional Claus treatment process only focuses on H₂S treatment but ignores CO₂. This article systematically conducted theoretical thermodynamic research on the thermocatalytic conversion of H₂S and CO₂. It was found that increasing the reaction temperature and H₂S ratio would have a positive impact on the reaction, while increasing the pressure would lead to a decrease in the conversion rate of reactants and product yield, and introducing COS into the feed gas could have a promoting effect on the reaction. Furthermore, 5 %Mo/Al₂O₃ catalyst was used to preliminarily explore the thermal and photothermal catalysis for H₂S and CO₂ conversion. The results showed that the photothermal catalysis significantly promoted the production of syngas (H₂ and CO), and suppressed COS production in contrast to thermal catalysis. This indicates that the introduction of light could effectively convert H₂S and CO₂ into high-value product syngas, providing important reference value for further research on the conversion of H₂S and CO₂.

A pyrene base luminophore was designed and synthesised under ambient conditions using [4+2] annulation. The synthesised probe PYINDP exhibits good optical properties and emits greenish blue, with high colour purity in solid, solution, and thin film phases. In solution, the CIE coordinates were found to be (0.20, 0.48), and for an aggregated state emitting deep green colour, the CIE values are (0.27, 0.65). Room temperature phosphorescence (RTP) is generated by the luminophore PYINDP, owing to the ISC process. Moreover, the emitter demonstrated an excellent limit of detection values in detecting nitroaromatics (NACs). Bio-imaging studies on HEK, A549 cell lines were successfully carried out to verify the staining capability of PYINDP in biological systems.