Dopant-Free Pyrene-Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells.

Dopant-free hole transporting materials (HTMs) is significant to the stability of perovskite solar cells (PSCs). Here, we developed a novel star-shape arylamine HTM, termed Py-DB, with a pyrene core and carbon-carbon double bonds as the bridge units. Compared to the reference HTM (termed Py-C), the extension of the planar conjugation backbone endows Py-DB with typical intermolecular π-π stacking interactions and excellent solubility, resulting in improved hole mobility and film morphology. In addition, the lower HOMO energy level of the Py-DB HTM provides efficient hole extraction with reduced energy loss at the perovskite/HTM interface. Consequently, an impressive power conversion efficiency (PCE) of 24.33 % was achieved for dopant-free Py-DB-based PSCs, which is the highest PCE for dopant-free small molecular HTMs in n-i-p configured PSCs. The dopant-free Py-DB-based device also exhibits improved long-term stability, retaining over 90 % of its initial efficiency after 1000 h exposure to 25 % humidity at 60 °C. These findings provide valuable insights and approaches for the further development of dopant-free HTMs for efficient and reliable PSCs.

Spin-orbit charge-transfer intersystem crossing in heavy-atom-free orthogonal covalent boron-dipyrromethene heterodimers.

Boron-dipyrromethene (BODIPY) derivatives are prospective organic-based triplet photosensitizers. Since the triplet generation yield of the parent BODIPY is low, heavy atoms are widely used to improve the triplet yield. However, the dimerization of BODIPYs can also significantly improve their ability to produce triplets. Through a comparative study of the triplet formation dynamics of two heavy-atom-free orthogonal covalent BODIPY heterodimers that differ in their dihedral angles, we have demonstrated that the mechanism of spin-orbit charge-transfer intersystem crossing (SOCT-ISC) promotes the triplet generation of BODIPY heterodimers in solution. Different from the general understanding of SOCT-ISC, the heterodimer with a smaller dihedral angle and low structural rigidity showed better triplet generation due to (a) the stronger inter-chromophoric interaction in the heterodimer, which promoted the formation of a solvent-stabilized charge-transfer (CT) state, (b) the more favorable energy level alignment with sizeable spin-orbit coupling strength, and (c) the balance between the stabilized singlet CT state and limited direct charge recombination to the ground state in a weakly polar solvent. The complete spectral characterization of the triplet formation dynamics clarified the SOCT-ISC mechanism and important factors affecting the triplet generation in BODIPY heterodimers.

Extending the π-Conjugated System in Spiro-Type Hole Transport Material Enhances the Efficiency and Stability of Perovskite Solar Modules.

Hole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl)-amine-9,9'-spirobifluorene (spiro-OMeTAD, termed "Spiro") is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro-type HTM (termed "DP") by substituting four anisole units on Spiro with 4-methoxybiphenyl moieties. By extending the π-conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP-based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small-area (0.06 cm2 ) devices and 21.86 % for modules (designated area of 27.56 cm2 ), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2 . The encapsulated DP-based devices maintain 95.1 % of the initial performance under ISOS-L-1 conditions after 2560 hours and 87 % at the ISOS-L-3 conditions over 600 hours.

The Impact of Load Style Variation on Gait Recognition Based on sEMG Images Using a Convolutional Neural Network.

Surface electromyogram (sEMG) signals are widely employed as a neural control source for lower-limb exoskeletons, in which gait recognition based on sEMG is particularly important. Many scholars have taken measures to improve the accuracy of gait recognition, but several real-time limitations affect its applicability, of which variation in the load styles is obvious. The purposes of this study are to (1) investigate the impact of different load styles on gait recognition; (2) study whether good gait recognition performance can be obtained when a convolutional neural network (CNN) is used to deal with the sEMG image from sparse multichannel sEMG (SMC-sEMG); and (3) explore whether the control system of the lower-limb exoskeleton trained by sEMG from part of the load styles still works efficiently in a real-time environment where multiload styles are required. In addition, we discuss an effective method to improve gait recognition at the levels of the load styles. In our experiment, fifteen able-bodied male graduate students with load (20% of body weight) and using three load styles (SBP = backpack, SCS = cross shoulder, SSS = straight shoulder) were asked to walk uniformly on a treadmill. Each subject performed 50 continuous gait cycles under three speeds (V3 = 3 km/h, V5 = 5 km/h, and V7 = 7 km/h). A CNN was employed to deal with sEMG images from sEMG signals for gait recognition, and back propagation neural networks (BPNNs) and support vector machines (SVMs) were used for comparison by dealing with the same sEMG signal. The results indicated that (1) different load styles had remarkable impact on the gait recognition at three speeds under three load styles (p < 0.001); (2) the performance of gait recognition from the CNN was better than that from the SVM and BPNN at each speed (84.83%, 81.63%, and 83.76% at V3; 93.40%, 88.48%, and 92.36% at V5; and 90.1%, 86.32%, and 85.42% at V7, respectively); and (3) when all the data from three load styles were pooled as testing sets at each speed, more load styles were included in the training set, better performance was obtained, and the statistical analysis suggested that the kinds of load styles included in training set had a significant effect on gait recognition (p = 0.002), from which it can be concluded that the control system of a lower-limb exoskeleton trained by sEMG using only some load styles is not sufficient in a real-time environment.

Dopant-Free Hole Transport Materials Afford Efficient and Stable Inorganic Perovskite Solar Cells and Modules.

The emerging CsPbI3 perovskites are highly efficient and thermally stable materials for wide-band gap perovskite solar cells (PSCs), but the doped hole transport materials (HTMs) accelerate the undesirable phase transition of CsPbI3 in ambient. Herein, a dopant-free D-π-A type HTM named CI-TTIN-2F has been developed which overcomes this problem. The suitable optoelectronic properties and energy-level alignment endow CI-TTIN-2F with excellent charge collection properties. Moreover, CI-TTIN-2F provides multisite defect-healing effects on the defective sites of CsPbI3 surface. Inorganic CsPbI3 PSCs with CI-TTIN-2F HTM feature high efficiencies up to 15.9 %, along with 86 % efficiency retention after 1000 h under ambient conditions. Inorganic perovskite solar modules were also fabricated that exhibiting an efficiency of 11.0 % with a record area of 27 cm2 . This work confirms that using efficient dopant-free HTMs is an attractive strategy to stabilize inorganic PSCs for their future scale-up.

Methylated Unsymmetric BODIPY Compounds: Synthesis, High Fluorescence Quantum Yield and Long Fluorescence Time.

We show that unsymmetric BODIPY compounds with one, two, and three methyl groups can be synthesized easily and efficiently by the unsymmetric reaction method. Their steady state and time-resolved fluorescence properties are examined in solvents of different polarity. These compounds show high fluorescence quantum yields (0.87 to 1.0), long fluorescence lifetimes (5.89 to 7.40 ns), and small Stokes shift (199 to 443 cm-1). The methyl substitution exhibits influence on the UV-Vis absorption and fluorescence properties, such as the blue shift in emission and absorption spectra. It is the number rather than the position of methyls that play major roles. Except for 3 M-BDP, the increase in the number of methyls on BODIPY core leads to the increase in both fluorescence quantum yield and radiative rate constant, but causes the decrease in fluorescence lifetime. H-bonding solvents increase both the fluorescence lifetime and quantum yields. The methylated BODIPYs show the ability to generate singlet oxygen (1Δg) which is evidenced by near-IR luminescence and DPBF chemical trapping techniques. The formation quantum yield of singlet oxygen (1Δg) for the compounds is up to 0.15 ± 0.05.

Effects of recipient oocyte source, number of transferred embryos and season on somatic cell nuclear transfer efficiency in sheep.

To improve the efficiency of somatic cell nuclear transfer (SCNT) in sheep, we investigated the effects of recipient oocyte source, number of transferred embryos and season on the pregnancy and live lamb rates for sheep somatic cell nuclear transfer embryos. Follicle-stimulating hormone (FSH)-stimulated ovaries produced significantly more oocytes both in total and of suitable quality for maturation culture than those without FSH treatment (from slaughterhouse). However, their in vitro maturation rates were similar. Embryos were reconstructed using adult fibroblast cells into enucleated MII oocytes. The pregnancy and term rates were significantly higher in the FSH-stimulated group than in the slaughterhouse one. Oocytes from FSH-stimulated ovaries were enucleated as recipient cytoplasm for nuclear transfer in the following experiments. The transfer of 7-9 and 11-13 embryos produced significantly higher pregnancy rates than that of six embryos. However, the former groups exhibited similar live lamb rates. FSH-stimulated ovaries produced significantly more oocytes in November and December (winter) than in May to July (summer), but the associated maturation rate did not increase. Pregnancy and term rates were significantly higher when transfer occurred in winter than in summer. In conclusion, FSH treatment produced significant benefit regarding the number and quality of collected oocytes and also for the pregnancy and live lamb rates for reconstructed embryos. However, the transfer of an appropriate number of embryos (7-13) and at an appropriate season (winter) increased pregnancy and term rates.

PET-based bisBODIPY photosensitizers for highly efficient excited triplet state and singlet oxygen generation: tuning photosensitizing ability by dihedral angles.

Herein, four covalent BODIPY heterodimers that differ by dihedral angles were shown to be highly efficient excited triplet state (T1) photosensitizers (PSs) for singlet oxygen formation with a quantum yield (ΦΔ) of up to 0.94 as compared to their respective monomers, which had only negligible ΦΔ of ca. 0.060. More interestingly, these PSs generate T1via charge recombination mechanism rather than traditional inter-system crossing. The photosensitizing ability of dimers is easily tuned by either the dihedral angle (between the two linked BODIPYs) or solvent polarity. Laser flash photolysis, time-resolved and steady state fluorescence, quantum chemical calculation, as well as thermodynamic analysis were employed to study the associated photophysical process to reveal the T1 formation mechanism: photo-induced electron transfer (PET) followed by charge recombination. Due to its heavy-atom-free nature, polarity selectivity, high efficiency, and easy tunability, this PET-based PS and its mechanism are very useful in developing new PS for photodynamic therapy of tumors, photobiology, and organic photochemistry.

The Fluorescence Properties of Three Rhodamine Dye Analogues: Acridine Red, Pyronin Y and Pyronin B.

The fluorescence spectra, fluorescence quantum yield, and fluorescence lifetime of Acridine Red (AR), Pyronin Y (PYY), and Pyronin B (PYB) in aqueous and organic solvents were measured by steady state fluorescence, time-correlated single photon counting, and electronic absorption methods. The rate constants of radiation and non radiation process (kf and kic) were calculated to elucidate the structural effect on the fluorescence mechanism. The data for each compound are compared with that of the corresponding rhodamine dye. AR showed significant longer lifetime and higher quantum yield than PYY and PYB, because the alkyls on N atom enhance the internal conversion (IC), the longer the alkyl the faster the IC. However, the structural variation does not alter the rate constant of radiation process (kf) but does change kic significantly. The phenyl in Rhodamine B or Rhodamine 6G shows only a slight effect on the fluorescence properties. Ethanol is the solvent in which all five compounds exhibit longest lifetime and highest fluorescence quantum yield.

Intracellular modulation of excited-state dynamics in a chromophore dyad: differential enhancement of photocytotoxicity targeting cancer cells.

The photosensitized generation of reactive oxygen species, and particularly of singlet oxygen [O2 (a(1) Δg )], is the essence of photodynamic action exploited in photodynamic therapy. The ability to switch singlet oxygen generation on/off would be highly valuable, especially when it is linked to a cancer-related cellular parameter. Building on recent findings related to intersystem crossing efficiency, we designed a dimeric BODIPY dye with reduced symmetry, which is ineffective as a photosensitizer unless it is activated by a reaction with intracellular glutathione (GSH). The reaction alters the properties of both the ground and excited states, consequently enabling the efficient generation of singlet oxygen. Remarkably, the designed photosensitizer can discriminate between different concentrations of GSH in normal and cancer cells and thus remains inefficient as a photosensitizer inside a normal cell while being transformed into a lethal singlet oxygen source in cancer cells. This is the first demonstration of such a difference in the intracellular activity of a photosensitizer.

Fluorescence properties of twenty fluorescein derivatives: lifetime, quantum yield, absorption and emission spectra.

The fluorescence lifetime (τf), emission quantum yield (Φf), absorption and emission spectral data of 20 fluorescein derivatives were measured under the same conditions by using time-correlated single photon counting, steady state fluorescence and absorption methods to get comparable data. Based on the results, the factors and mechanism that control the fluorescence properties of the fluorescein dyes are discussed. Both Φf and τf are remarkably dependent on the substitution on either xanthene or phenyl rings, but their ratio (Φf/τf), i.e. rate constant of radiation process, is a constant value (0.20 × 10(9) s(-1)). The rate constant of nonradiation process, on the other hand, is varied with both the structure and the solvent used.

Design Strategies for Aqueous Zinc Metal Batteries with High Zinc Utilization: From Metal Anodes to Anode-Free Structures.

Aqueous zinc metal batteries (AZMBs) are promising candidates for next-generation energy storage due to the excellent safety, environmental friendliness, natural abundance, high theoretical specific capacity, and low redox potential of zinc (Zn) metal. However, several issues such as dendrite formation, hydrogen evolution, corrosion, and passivation of Zn metal anodes cause irreversible loss of the active materials. To solve these issues, researchers often use large amounts of excess Zn to ensure a continuous supply of active materials for Zn anodes. This leads to the ultralow utilization of Zn anodes and squanders the high energy density of AZMBs. Herein, the design strategies for AZMBs with high Zn utilization are discussed in depth, from utilizing thinner Zn foils to constructing anode-free structures with theoretical Zn utilization of 100%, which provides comprehensive guidelines for further research. Representative methods for calculating the depth of discharge of Zn anodes with different structures are first summarized. The reasonable modification strategies of Zn foil anodes, current collectors with pre-deposited Zn, and anode-free aqueous Zn metal batteries (AF-AZMBs) to improve Zn utilization are then detailed. In particular, the working mechanism of AF-AZMBs is systematically introduced. Finally, the challenges and perspectives for constructing high-utilization Zn anodes are presented.

Microbial mechanisms regulate soil organic carbon mineralization under carbon with varying levels of nitrogen addition in the above-treeline ecosystem.

Climate change is leading to the upward migration of treelines in mountainous regions, resulting in changes to the carbon and nitrogen inputs in soils. The impact of these alterations on the microbial mineralization of the existing soil organic carbon (SOC) pool remains uncertain, making it challenging to anticipate their effects on the carbon balance. To enhance our prediction and understanding of native SOC mineralization in Himalayan regions resulting from treeline shifts, a study was conducted to quantify soil priming effects (PEs) at high elevations above the treeline ecosystem. In laboratory incubation, soils were treated with a combination of 13C-glucose and varying nitrogen rates, along with carbon-only treatments and control groups without any amendments. The addition of carbon with varying nitrogen addition rates exhibited diverse PEs on native SOC. A highly positive PE was observed under low nitrogen input due to a high carbon/nitrogen imbalance and increased L-leucine aminopeptidase (LAP) activity, coupled with low nitrogen availability and carbon use efficiency (CUE). In contrast, a positive PE declined following high nitrogen input due to a low carbon/nitrogen imbalance and LAP activity, coupled with high nitrogen availability and CUE. These findings support the concept that multiple mechanisms (i.e., microbial nitrogen mining and microbial metabolic efficiency) exist that regulate SOC mineralization under the addition of carbon with varying nitrogen rates. Thus, an increase in nitrogen availability fulfils microbial nitrogen demand, reduces the microbial carbon/nitrogen imbalance, decreases enzyme activity that requires nitrogen and enhances microbial metabolic efficiency. Consequently, this mechanism reduces the positive PE, thereby serving as a potential tool for stabilizing native SOC in above-treeline ecosystems.

A Multifunctional Dye Molecule as the Interfacial Layer for Perovskite Solar Cells.

In perovskite solar cells (PSCs), defects in the interface and mismatched energy levels can damage the device performance. Improving the interface quality is an effective way to achieve efficient and stable PSCs. In this work, a multifunctional dye molecule, named ThPCyAc, was designed and synthesized to be introduced in the perovskite/HTM interface. On one hand, various functional groups on the acceptor unit can act as Lewis base to reduce defect density and suppress nonradiative combinations. On the other hand, the stepwise energy-level alignment caused by ThPCyAc decreases the accumulation of interface carriers for facilitating charge extraction and transmission. Therefore, based on the ThPCyAc molecule, the devices exhibit elevated open-circuit voltage and fill factor, resulting in the best power conversion efficiency (PCE) of 23.16%, outperforming the control sample lacking the interface layer (PCE = 21.49%). Excitingly, when attempting to apply it as a self-assembled layer in inverted devices, ThPCyAc still exhibits attractive behavior. It is worth noting that these results indicate that dye molecules have great potential in developing multifunctional interface materials to obtain higher-performance PSCs.

3D Conjugated Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells and Modules.

The orthogonal structure of the widely used hole transporting material (HTM) 2,2',7,7'-tetrakis(N, N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD) imparts isotropic conductivity and excellent film-forming capability. However, inherently weak intra- and inter-molecular π-π interactions result in low intrinsic hole mobility. Herein, a novel HTM, termed FTPE-ST, with a twist conjugated dibenzo(g,p)chrysene core and coplanar 3,4-ethylenedioxythiophene (EDOT) as extended donor units, is designed to enhance π-π interactions, without compromising on solubility. The three-dimensional (3D) configuration provides the material multi-direction charge transport as well as excellent solubility even in 2-methylanisole, and its large conjugated backbone endows the HTM with a high hole mobility. Moreover, the sulfur donors in EDOT units coordinate with lead ions on the perovskite surface, leading to stronger interfacial interactions and the suppression of defects at the perovskite/HTM interface. As a result, perovskite solar cells (PSCs) employing FTPE-ST achieve a champion power conversion efficiency (PCE) of 25.21% with excellent long-time stability, one of the highest PCEs for non-spiro HTMs in n-i-p PSCs. In addition, the excellent film-forming capacity of the HTM enables the fabrication of FTPE-ST-based large-scale PSCs (1.0 cm2) and modules (29.0 cm2), which achieve PCEs of 24.21% (certificated 24.17%) and 21.27%, respectively.

Event-Triggered Communication-Based Control for Strict-Feedback Nonlinear Systems.

In this article, we shall investigate the event-triggered communication control problem for strict-feedback nonlinear systems with measurement outputs. First, two event-triggered communication schemes are designed. Based on both event-triggered schemes, the measurement output and control input signals are only transmitted at triggering time instants, which saves communication costs from the sensor to the controller and from the controller to the actuator. Meanwhile, Zeno behavior can be excluded under the proposed triggering schemes. Second, since the full-state information is not available to the controller, by developing an observer, the system state is estimated and a controller based on estimated state information is designed. Due to the irregular sampling of information communication and state estimation error affects each other, the parameters of the state observer, the controller, and the event-triggering mechanism should be jointly designed. It is proved that the closed-loop system state converges to the origin. Finally, a simulation example verifies the validity of the obtained theoretical result.

Photophyical and photosensitizing properties of BODIPYs substantially changed by alkyl- and phenyl-amino groups on meso carbon.

meso-RNH (R = C3H7, C4H9, PhCH2, H, and Ph) substituted BODIPY compounds have been prepared to examine their photophysical properties and photosensitizing abilities. We have measured the UV-vis absorption, steady state and time resolved fluorescence, excited triplet state formation using laser flash photolysis, singlet oxygen generation ability using chemical trapping method. The results show that the presence of meso-RNH leads to large blue shift of absorption and emission wavelength, remarkable decrease in fluorescence quantum yield and lifetime values, and significant increase in singlet oxygen formation quantum yield. Quantum chemical calculation also reveals the photoinduced charge transfer (PCT) mechanism. We conclude that property changes are due to: 1) S0 and S1 geometry, 2) ground state structural isomerization, and 3) intramolecular PCT. These results and mechanisms are helpful for designing new functional materials.

Topological analysis of functional connectivity in Parkinson's disease.

Parkinson's disease (PD) is a clinically heterogeneous disorder, which mainly affects patients' motor and non-motor function. Functional connectivity was preliminary explored and studied through resting state functional magnetic resonance imaging (rsfMRI). Through the topological analysis of 54 PD scans and 31 age-matched normal controls (NC) in the Neurocon dataset, leveraging on rsfMRI data, the brain functional connection and the Vietoris-Rips (VR) complex were constructed. The barcodes of the complex were calculated to reflect the changes of functional connectivity neural circuits (FCNC) in brain network. The 0-dimensional Betti number ß0 means the number of connected branches in VR complex. The average number of connected branches in PD group was greater than that in NC group when the threshold δ ≤ 0.7. Two-sample Mann-Whitney U test and false discovery rate (FDR) correction were used for statistical analysis to investigate the FCNC changes between PD and NC groups. In PD group, under threshold of 0.7, the number of FCNC involved was significantly differences and these brain regions include the Cuneus_R, Lingual_R, Fusiform_R and Heschl_R. There are also significant differences in brain regions in the Frontal_Inf_Orb_R and Pallidum_R, when the threshold increased to 0.8 and 0.9 (p < 0.05). In addition, when the length of FCNC was medium, there was a significant statistical difference between the PD group and the NC group in the Neurocon dataset and the Parkinson's Progression Markers Initiative (PPMI) dataset. Topological analysis based on rsfMRI data may provide comprehensive information about the changes of FCNC and may provide an alternative for clinical differential diagnosis.

High-Throughput Sequencing Reveals a Dynamic Bacterial Linkage between the Captive White Rhinoceros and Its Environment.

Soil is an essential part of the animal habitat and has a large diversity of microbiota, while the animal body was colonized by a complex bacterial community; so far, the relationship between the animal host microbial community and the soil microbial ecosystem remains largely unknown. In this study, 15 white rhinoceros from three different captive grounds were selected and the bacterial community of the gut, skin, and environment of these rhinoceros were analyzed by 16S rRNA sequencing technology. Our results showed that Firmicutes and Bacteroidota were the predominant phyla in the gut microbiome, whereas skin and environment samples share similar microbiome profiles and are dominated by the phyla of Actinobacteriota, Chloroflexi, and Proteobacteria. Although the bacterial composition of the gut differs from that of the skin and environment, the Venn diagrams showed that there were 22 phyla and 186 genera shared by all the gut, skin, and environmental microbes in white rhinoceroses. Further cooccurrence network analysis indicated a bacterial linkage based on a complex interaction was established by the bacterial communities from the three different niches. In addition, beta diversity and bacterial composition analysis showed that both the captive ground and host ages induced shifts in the microbial composition of white rhinoceroses, which suggested that the bacterial linkage between the captive white rhinoceros and its environment is dynamic. Overall, our data contribute to a better understanding of the bacterial community of the captive white rhinoceros, especially for the relationship between the environment and animal bacterial communities. IMPORTANCE The white rhinoceros is one of the world's most endangered mammals. The microbial population plays a key role in animal health and welfare; however, studies regarding the microbial communities of the white rhinoceros are relatively limited. As the white rhinoceros has a common behavior of mud baths and thus is in direct contact with the environment, a relationship between the animal microbial community and the soil microbial ecosystem appears possible, but it remains unclear. Here, we described the characteristics and interaction of bacterial communities of the white rhinoceros in three different niches, including gut, skin, and environment. We also analyzed the effects of captive ground and age on the composition of the bacterial community. Our findings highlighted the relationship among the three niches and may have important implications for the conservation and management of this threatened species.

Ultrafast Charge Separation Driven by Torsional Motion in Orthogonal Boron Dipyrromethene Dimer.

In this work, the photoinduced charge separation (CS) via symmetry breaking in an orthogonal meso-ß-linked boron dipyrromethene (BODIPY) dimer was investigated by polarized transient absorption spectroscopy. The time constant about 0.76 ps of the CS reaction determined in dimethyl sulfoxide is much faster than the solvation dynamics. The observed transient anisotropy of the BODIPY anion band implies that both hole and electron transfers occur with similar probabilities. The bidirectional charge transfer processes suggest that the locally excited state is weakly coupled to the polar solvent, and the solvation coupled excited-state structural relaxation within the BODIPY monomeric unit is rather limited. In combination with the electronic excitation analysis based on time-dependent density-functional theory calculations, we deduced that the CS in the orthogonal BODIPY dimer is enabled via the torsional motion associated with covalently connected BODIPY units, promoting the electronic coupling, and irrelevant to the dynamic solvent relaxation.