Covalent organic frameworks (COFs) are of great potential as adsorbents owing to their tailorable functionalities, low density and high porosity. However, their intrinsically stacked two‐dimensional ...(2D) structure limits the full use of their complete surface for sorption, especially the internal pores. The construction of ultrathin COFs could increase the exposure of active sites to the targeted molecules in a pollutant environment. Herein, an ultrathin COF with a uniform thickness of ca. 2 nm is prepared employing graphene as the surface template. The resulting hybrid aerogel with an ultralow density (7.1 mg cm−3) exhibits the ability to remove organic dye molecules of different sizes with high efficiency. The three‐dimensional (3D) macroporous structure and well‐exposed adsorption sites permit rapid diffusion of solution and efficient adsorption of organic pollutants, thereby, greatly contributing to its enhanced uptake capacity. This work highlights the effect of COF layer thickness on adsorption performance.
An ultrathin anionic covalent organic framework (COF) was constructed homogeneously on the surface of a graphene template via a facile hydrothermal method. Compared with bulk COF powder, the anionic ultrathin COF exhibited the ability to remove cationic organic dyes of different sizes with higher efficiency.
Designed with a symmetrical naphthatetrathiophene (NTT) core and triphenylamine (TPA)-based side arms, a series of novel organic small molecule hole-transporting materials are simulated for ...perovskite solar cells (PSCs) using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. As a fundamental understanding, the energy level alignments and the charge transport behavior are explored for their potential applications. Our results show that, adding an oxygen-bridge between the neighboring phenyl groups of TPA side arms makes the highest occupied molecular orbital (HOMO) levels up-shift, whereas the carbon-carbon single bond stabilizes the HOMOs by about 0.3-0.4 eV. By structural tailoring of the TPA side arms, the HOMO levels of newly designed molecules range from -5.08 eV to -5.61 eV, which provides more possibilities for the interfacial energy regulation. Meanwhile, our results also indicate that the quasi-planar molecular architecture and the delocalized frontier molecular orbitals can effectively enhance the electronic coupling between adjacent molecules. In addition, the reorganization energies are distinctly lowered in the cases of the mixed carbon-carbon bond and oxygen-bridge, and the double oxygen-bridge models. As a result, these molecules with the additional carbon-carbon bond and oxygen-bridge exhibit high hole mobilities. Several promising candidates are proposed toward more efficient PSCs, and more importantly, this work offers some new insights for the design of organic small molecule materials.
An organoboron small-molecular acceptor (OSMA) M
containing a boron-nitrogen coordination bond (B←N) exhibits good light absorption in organic solar cells (OSCs). In this work, based on M
, OSMA M
, ...with the incorporation of a boron-nitrogen covalent bond (B-N), was designed. We have systematically investigated the charge-transport properties and interfacial charge-transfer characteristics of M
, along with M
, using the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT). Theoretical calculations show that M
can simultaneously boost the open-circuit voltage (from 0.78 V to 0.85 V) and the short-circuit current due to its high-lying lowest unoccupied molecular orbital and the reduced energy gap. Moreover, its large dipole shortens stacking and greatly enhances electron mobility by up to 5.91 × 10
cm
·V
·s
. Notably, the excellent interfacial properties of PTB7-Th/M
, owing to more charge transfer states generated through the direct excitation process and the intermolecular electric field mechanism, are expected to improve OSCs performance. Together with the excellent properties of M
, we demonstrate a new OSMA and develop a new organoboron building block with B-N units. The computations also shed light on the structure-property relationships and provide in-depth theoretical guidance for the application of organoboron photovoltaic materials.
The design of new molecules with theoretical chemistry methods and further obtaining a fundamental understanding of the structure-property relationship are important for the development of ...high-efficiency hole-transporting materials (HTMs). Herein, the effect of semi-locked and fully-locked cores was systematically investigated based on two conformation-tunable tetrathienylethene (TTE) and tetraphenylethylene (TPE) units. Our results show that the highest occupied molecular orbital (HOMO) levels of the locked TTE-2 and TTE-3 are clearly down-shifted compared with that of the unlocked TTE-1, which is due to the decreased electronic conjugation between the locked cores and the triphenylamine (TPA) arms, whereas the same situation is not found for TPE-3 due to the twisted core configuration. Compared with the TTE-series, the TPE-series exhibits less optical absorption in the visible light region and enhanced stability. Meanwhile, the hole mobility of the designed HTMs displays an increased trend from the unlocked core to the semi-locked and fully-locked cores due to the gradually increasing hole transfer integral with enhanced molecular planarity. In addition, we also found that the reorganization energy of the locked TTE cores is obviously lowered compared to that of the unlocked one, which plays an important role in increasing the hole mobility. In summary, this work can provide some useful clues for designing high-efficiency two-dimensional HTMs, and two potential promising candidates (TTE-3 and TPE-3) are proposed.
The influence of the core on the performance of small molecule HTMs is investigated by using quantum chemistry methods, and potential HTMs are proposed.
PEDOT has been widely used in advanced electronics, and one of the keys to determine the performance is hole mobility. PEDOT commonly shows amorphous morphology ascribed to the flexibility of its ...backbone, giving rise to a wide difference in mobility. To boost the mobility, one generally introduces an ionic liquid (IL) to modulate the morphology to be more ordered. To estimate the mobility, one needs to do molecular dynamics (MD) simulations to acquire the abundant conformers, then to investigate the transfer integral (
V
ij
)
via
quantum mechanics (QM) calculations theoretically or
via
quantum Hall effect measurements experimentally. Here, with the help of machine learning (ML) technology (involving supervised learning algorithms of linear regression (LR), artificial neural network (ANN), random forest (RF), and gradient boosting decision tree (GBDT)), we can predict
V
ij
accurately compared to the routine MD → QM method (for ANN and RF,
R
2
> 0.9 and MAE = 10
−3
eV), while shortening the prediction time by 6 orders of magnitude. Generalization verification on an additional five IL-PEDOT cases confirms the predictive ability of the model. Then, the predicted
V
ij
was used to estimate the mobility. Finally, representative IL EMIMTFSI-regulated PEDOT aqueous solutions with different concentrations were experimentally characterized by AFM and conductivity measurements, the conductivity being in line with the change tendency of the estimated mobility. This alternative ML model opens up new perspectives for ultrafast prediction of the mobility of IL-PEDOT in any morphology and can be transferred to other analogs before real device construction.
PEDOT has been widely used in advanced electronics, and one of the keys to determine the performance is hole mobility.
Porous carbon materials (PCMs) play a pivotal role in diverse applications, such as energy storage, adsorption, catalysis, environmental remediation, and microwave adsorption. The selection of carbon ...precursors, in particular, is crucial for tailoring porous structures with specific functionalities. Biomass, with its rich carbon feedstock, abundant availability, renewability, and versatile structures, has emerged as a promising precursor for porous carbon material synthesis. This review comprehensively summarizes the recent advances in biomass-derived porous carbon materials (BPCMs) encompassing synthetic strategy, morphology, structural composition, and multiple applications. We first review synthetic approaches aiming at regulating porosity, followed by morphological and composition features of BPCMs, with a special emphasis on elucidating the dimensional clarification and heteroatom doping effects. The discussion then extends to the wide-ranging applications of BPCMs, covering energy-related applications and CO
2
adsorption to environmental remediation. Finally, the review outlines the existing challenges and prospects in the field. In summary, this review systematically describes BPCMs and provides valuable guidance for researchers to select and synthesize BPCMs that meet specific functional requirements.
Poly(3,4-ethylenedioxythiophene) (
PEDOT
) has aroused great interest in organic electrics because of its high electrical conductivity and mechanical flexibility. To improve the charge transport, it ...can act as an ionic liquid (IL) additive due to its ion characteristics and high electrical conductivity. Herein, we investigated the hole-transport performance of
PEDOT
treated by ILs featuring specific ion ratios (4 : 1, 3 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 3, and 1 : 4) of the cation and anion through classical dynamics simulations and quantum mechanics computations. The hole mobility of the amorphous
PEDOT
, constituting nine EDOT monomers, could be improved to 16.81, 18.03, and 10.14 cm
2
V
−1
s
−1
when synergistically regulating the ion ratio to 2 : 1, 3 : 1, and 4 : 1. Consequently, these ratios potentially achieved nearly a 100-fold improvement in the electrical conductivity with respect to the pristine system. The improvements mainly stemmed from the fact that decreasing the amount of anions in ILs and prolonging the chain length of
PEDOT
yielded an ordered face-to-face π-π stacking. The electronic coupling and charge excitation further confirmed that the anions play an active role in tunneling the hole transport in ILs/heterogeneous
PEDOT
, and the highest occupied molecular orbital (HOMO) energy level of
PEDOT
was up-shifted significantly after treatment by the ratios of 2 : 1, 3 : 1, and 4 : 1, which favored the electron-donating ability and was in line with the extraordinary enhancement of the hole mobility. Our results imply that regulating the ion ratio in ILs is a novel strategy for modulating the electronic properties and π-stacked morphology of
PEDOT
.
Poly(3,4-ethylenedioxythiophene) (
PEDOT
) has aroused great interest in organic electrics because of its high electrical conductivity and mechanical flexibility.
A novel AIE-active molecule ( TPEThRB ) composed of a tetraphenylethene unit, Rhodamine spirolactam, as a receptor, and thiophene ring as a conjugated electron-rich linker was obtained. It can be ...utilized to effectively detect trivalent metal cations and H + ions, accompanied with visible color change and turn-on fluorescence enhancement. The four species can be further recognized individually through UV-Vis analysis. Moreover, compared to the conventional manner of metal ion chelation-induced ring-opening form of Rhodamine B derivative, the interaction of TPEThRB with trivalent cations is ascribed to the synergy of proton-induced open-cycle and the subsequent coordination interaction due to the steric effect and acidic hydrolysis of trivalent metal cations. In addition, in view of its acidochromism property with reversible color and fluorescence changes, AIE-active TPEThRB may be a prominent smart material for data protection by employing trifluoroacetic acid vapor as the chromogenic reagent and diethylamine vapor as the eraser. Owing to the AIE characteristics and the remarkable photophysical response characteristics towards trivalent metal ions in vitro , TPEThRB is suitable for fluorescence ratio imaging of trivalent metal cations in living cells.
The Ru-catalyzed carbonylation of alkenes with CO2 as a C1 surrogate and imidazole chlorides as the promotor is investigated by a combination of computational and experimental study. The conversion ...rate of CO2 to CO is positively correlated with the efficiency of both hydroesterification and hydroformylation, which is found facilitated in the presence of chloride additives with a decreasing order of BmimCl ∼ B3MimCl > BmmimCl ∼ LiCl. Taking the hydroesterification with MeOH as a representative example, BmimCl bearing C–H functionality at the C2 site of the cation assists the reduction of CO2 to CO as a hydrogen donor medium, with the anion and cation acting in a synergistic fashion. Subsequent insertion of CO2 into the formed Ru–H bond with the assistance of chloride anion produces the Ru–COOH species, which ultimately accelerates the activation of CO2.
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•An in-depth understanding of the ligand-free Ru-catalyzed carbonylation of alkenes with CO2 as a C1 surrogate is accessed.•The conversion of CO2 is positively correlated with the efficiency of both hydroesterification and hydroformylation of alkenes.•The crucial role of imidazolium chlorides in CO2 reduction is elucidated, with the synergistic fashion of anion and cation.
Multiple absorbers that function in different absorption regions (near infra-red (NIR) and UV-Visible (UV-Vis)) have been widely used in solar cell applications to enhance the light-harvesting. ...Herein, two special co-sensitizing Models
1
and
2
, which feature either saturated dye IQ21 or saturated co-sensitizer S2, have been added to a TiO
2
surface to explore the effect of the altered sensitizing sequence, namely the co-sensitizing ratio of IQ21/S2 and S2/IQ21 on the electrostatic potential variation (Δ
V
), electron injection efficiency (
η
inj
′), and Förster resonance energy transfer (FRET), using density functional theory and first-principle molecular dynamics simulations. The Δ
V
related to the open-circuit voltage (
V
oc
) is insensitive in both Models
1
and
2
. However, the absorption (
λ
abs
) and
η
inj
′ associated with the short-circuit density (
J
sc
) display a significant deviation (the
λ
abs
for
1
is red-shifted compared to that of
2
, and the
η
inj
′ for
1
is improved by 56%). Meanwhile, Model
1
manifests a suppressed FRET and potentially favors co-sensitizer S2 functioning as the electron-injector and not the energy-donor. Another two possible Models
3
and
4
that feature a reduced adsorption of IQ21 and S2 relative to
1
and
2
were considered further, and the result mirrors the main trend in
1
and
2
, except for the
η
inj
′. Overall, it implies that sensitizing a larger absorber with NIR features to saturate it first, then introducing a smaller absorber with UV-Vis features, can potentially improve the electron injection and diminish electron-hole recombination considerably. Our results provide a comprehensive analysis of the active role of an optimized sensitizing sequence to improve the conversion efficiency.
Multiple absorbers that function in different absorption regions (near infra-red (NIR) and UV-Visible (UV-Vis)) have been widely used in solar cell applications to enhance the light-harvesting.
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