Formation Of Charge-transfer Complex Research Articles

Unveiling the enhanced optical limiting of polyaniline – Fullerene composite investigated by z-scan

The reverse saturable absorption (RSA) and optical limiting (OL) mechanisms of polyaniline (PANI) and fullerene doped PANI (PANI-C60) solutions were investigated by open-aperture z-scan studies, using a nanosecond pulsed Nd:YAG laser operating at 532 nm wavelength as the excitation source. The nonlinear absorption coefficient (β), OL threshold, and imaginary part of nonlinear susceptibility (χi(3)) of PANI and PANI-C60 solutions were determined for three different laser input pulse energies and are found to be in the order of 10−9 cm/W, 106 W/cm2, and 10−10 esu respectively. The results showed enhanced OL efficiency for the PANI-C60 solution, making it a promising candidate for applications in optoelectronics and optical limiting. The transmission electron microscope (TEM) images revealed the uniform distribution of C60 of particle size in the range of 5–10 nm in the PANI matrix. The composite formation of PANI-C60 was confirmed by Fourier transform infrared spectroscopy (FTIR). The presence of C60 and its charge transfer complex (CTC) formation with PANI are responsible for the enhanced OL efficiency. The linear refractive index values were measured using UV–Visible absorption spectra and compared with the theoretical values. The investigation of the OL mechanism and the calculation of its associated NLO parameters for PANI and PANI-C60 solutions are reported for the first time.

Synthesis and high-temperature energy storage performances of fluorinated polyimides

In light of the increasingly stringent requirements for the applications of light-weight flexible high-temperature-resistant dielectric materials in the fields of aerospace, electronics, and electric vehicles, the imperative lies in the development of dielectric materials with high discharged energy density, enduring temperature resistance and high reliability. This work introduced side-chain trifluoromethyl (–CF3) groups into high-temperature engineering polymer polyimides and conducted comprehensive studies on the breakdown and energy storage capabilities. The introduction of bulky –CF3 substituents reduces the intermolecular interactions, increases the free volume, and suppresses the high-temperature leakage conductance loss by decreasing the formation of intermolecular charge transfer complexes between polymer chains. As a result, the fluorinated polyimides (PFI) with lower dielectric constant exhibit enhanced breakdown strengths (730 MV m−1 at 25 °C; 630 MV m−1 at 150 °C), leading to a high discharged energy density of 3.6 J cm−3 (∼1.7 times of pristine polyimides), alongside a charge-discharge energy efficiency of ∼80% at 150 °C. These findings underscore the great potential of PFI for applications in the field of high-temperature energy storage.

Development of Two Eco-Friendly and High-Throughput Microwell Spectrophotometric Methods for Analysis of an Antibacterial Drug Tulathromycin in Pharmaceutical Bulk Form.

Tulathromycin (TUL) is a triamilide antibacterial drug which has been approved for use in the European Union and the United States for the treatment and prevention of bovine respiratory diseases. The existing methods for determination of TUL in its pharmaceutical bulk form are very limited and suffer from major drawbacks. The aim of this study was the development of two innovative microwell spectrophotometric methods (MW-SPMs) for determination of TUL in its pharmaceutical bulk form. The formation of charge transfer complexes (CTCs) of TUL, as an electron donor, was investigated with 2,5-dihydroxy-3,6-dichlorocyclohexa-2,5-diene-1,4-dione (HCD) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (CBQ), as π-electron acceptors. The CTCs were characterized by using UV-visible spectrophotometry and computational calculations. The reactions were employed for the development of two MW-SPMs with a one-step for the quantitative analysis of TUL. The formation of CTCs was confirmed via the formation of characteristic absorption bands with maximum absorption at 520 and 460 nm for CTCs with HCD and CBQ, respectively. The stoichiometry of both CTCs was found to be 1:1, and the values of different spectroscopic and electronic constants confirmed the stability of the CTCs. The mechanisms of the reactions were postulated. The linear range of both MW-SPMs was 10-500 µg/mL. The limits of quantitation were 13.5 and 26.4 µg/mL for methods involving reactions with HCD and CBQ, respectively. Both methods were successfully applied to the quantitation of TUL in pharmaceutical bulk form with acceptable accuracy and precision. The results of eco-friendliness/greenness assessment proved that both MW-SPMs fulfill the requirements of green analytical approaches. In addition, the one-step reactions and simultaneous handling of a large number of samples with micro-volumes in the proposed methods gave them the advantage of high throughput analysis. This study described two new MW-SPMs as valuable analytical tools for the determination of TUL.

Nanoscale mapping of relativistic photocarrier transports in epitaxial graphene surface and edge states

We report the direct mapping of photo-transport properties of relativistic carriers generated on terrace-surface and terrace-edge structures of epitaxial graphene grown on silicon carbide. In this method, a conductive probe made a direct contact with epitaxial graphene and scanned the surface, allowing us to map the topography, current, and noise of graphene with nanoscale resolutions via a scanning noise microscopy. The maps were further analyzed by a two-dimensional network model to obtain the sheet-conductance (S□) and noise-source density (neff) distributions of epitaxial graphene. The topography image showed the formation of terraces, which could be attributed to the different decomposition rate of silicon atoms during the graphene growth. The terraces of graphene exhibited uniform S□, being separated by one-dimensional terrace-edges. Interestingly, terrace-edges exhibited a rather large neff with a power-law relationship of S□ ∝ neff−0.5, indicating a typical hopping conduction. However, in terrace-surfaces, sheet-conductance was nearly independent on neff, which was attributed to the relativistic nature of charge carriers unaffected by charge-trapping potential. Notably, under illumination, we observed the relativistic behavior of photocarriers in overall graphene terraces, presumably because photocarriers were generated through charge-transfer complexes formation at epitaxial graphene/substrate interface without the participation of noise-sources. Interestingly, we observed nearly homogeneous photoconductance and neff, which could be possibly due to the merger of one-dimensional edge-states into two-dimensional surface-states. The mapping of photoconductance and photo-traps provides valuable insights into the generation of relativistic photocarriers in epitaxial graphene.

Electrophile-mediated ionic liquid strategy for transforming inert natural polymers into highly active iodine adsorbents

The separation and conversion of gas resources are crucial aspects of sustainable energy development. Developing general methods to overcome bottlenecks in gas adsorption and conversion within natural polymers is an urgent global concern. In this work, the use of ionic liquids as electrophiles was proposed, and the Ionic Liquid Solution Process (ILSP) was employed to prepare alginate polymers-based on natural polymers. ILSP achieved a remarkable 0-to-1 transformation in gaseous iodine adsorption, converting inactive alginic acid (∼0 g g−1 in saturated adsorption capacity) into a highly active iodine adsorbent (5.24 g g−1). It was revealed that electrophiles effectively regulated the electron cloud distribution of functional groups by replacing acidic protons on alginic acid, exerting a volumetric effect. This increased the electron density near the deprotonated carboxylic groups, enhancing the nucleophilicity of carboxylic groups. Consequently, it promoted halogen interaction between electron-rich oxygen atoms and iodine during adsorption, thereby improving the efficiency of charge transfer complex formation and polyiodide ion conversion. The ILSP strategy could provide guidance for the separation and conversion of gases such as iodine, carbon dioxide, and hydrogen.

Theory-driven design of phosphazene-based porous polymer beads for enhanced iodine adsorption

Efficient adsorbents for radioiodine removal play a crucial role in safeguarding public and ecology health. However, conventional trial-and-error approaches for designing such high-performance adsorbents suffer from limited efficiencies. Herein, we employed a rational design strategy guided by precise density functional theory (DFT) calculations to synthesize a polyphosphazene-based microsphere tailored for iodine capture. Theoretical calculations quantifying the interactions of iodine molecules with diverse nitrogen-containing organic groups reveal the superior affinity of phosphazene groups with I2. Motivated by these findings, we judiciously designed a poly(bis(diethylamino)) phosphazene (PDEP) with a high density of active adsorption sites. Subsequently, PDEP was integrated into a composite bead with polyether sulfone (denote as PDEP@PES) for practical applications. PDEP@PES exhibits an elevated static adsorption capacity of 1.08 g/g, surpassing the majority of reported beads. More importantly, under a high flow rate of 200 mL/min, the dynamic uptake amount of PDEP@PES reaches 78.8 mg/g, outperforming pristine PES beads (3.19 mg/g) and commercial silver-impregnated silica gel (23.0 mg/g). The XPS results confirm the formation of robust charge-transfer complex between phosphazene groups with I2. This was further supported by their substantial interaction energy of -20.59 kcal/mol, as determined by DFT calculations. Our study demonstrates the high feasibility of polyphosphazene-based microspheres for radioiodine removal, shedding light on the enormous potential of theory-driven design paradigm for the development of exceptional adsorbents for environmental remediation.

Reductive Doping Inhibits the Formation of Isomerization‐Derived Structural Defects in N‐doped Poly(benzodifurandione) (n‐PBDF)

AbstractRecently, solution‐processable n‐doped poly(benzodifurandione) (n‐PBDF) has been made through in‐situ oxidative polymerization and reductive doping, which exhibited exceptionally high electrical conductivities and optical transparency. The discovery of n‐PBDF is considered a breakthrough in the field of organic semiconductors. In the initial report, the possibility of structural defect formation in n‐PBDF was proposed, based on the observation of structural isomerization from (E)‐2H,2′H‐[3,3′‐bibenzofuranylidene]‐2,2′‐dione (isoxindigo) to chromeno[4,3‐c]chromene‐5,11‐dione (dibenzonaphthyrone) in the dimer model reactions. In this study, we present clear evidence that structural isomerization is inhibited during polymerization. We reveal that the dimer (BFD1) and the trimer (BFD2) can be reductively doped by several mechanisms, including hydride transfer, forming charge transfer complexes (CTC) or undergoing an integer charge transfer (ICT) with reactants available during polymerization. Once the hydride transfer adducts, the CTC, or the ICT product forms, structural isomerization can be effectively prevented even at elevated temperatures. Our findings provide a mechanistic understanding of why isomerization‐derived structural defects are absent in n‐PBDF backbone. It lays a solid foundation for the future development of n‐PBDF as a benchmark polymer for organic electronics and beyond.

Reductive Doping Inhibits the Formation of Isomerization-Derived Structural Defects in N-doped Poly(benzodifurandione) (n-PBDF).

Recently, solution-processable n-doped poly(benzodifurandione) (n-PBDF) has been made through in-situ oxidative polymerization and reductive doping, which exhibited exceptionally high electrical conductivities and optical transparency. The discovery of n-PBDF is considered a breakthrough in the field of organic semiconductors. In the initial report, the possibility of structural defect formation in n-PBDF was proposed, based on the observation of structural isomerization from (E)-2H,2'H-[3,3'-bibenzofuranylidene]-2,2'-dione (isoxindigo) to chromeno[4,3-c]chromene-5,11-dione (dibenzonaphthyrone) in the dimer model reactions. In this study, we present clear evidence that structural isomerization is inhibited during polymerization. We reveal that the dimer (BFD1) and the trimer (BFD2) can be reductively doped by several mechanisms, including hydride transfer, forming charge transfer complexes (CTC) or undergoing an integer charge transfer (ICT) with reactants available during polymerization. Once the hydride transfer adducts, the CTC, or the ICT product forms, structural isomerization can be effectively prevented even at elevated temperatures. Our findings provide a mechanistic understanding of why isomerization-derived structural defects are absent in n-PBDF backbone. It lays a solid foundation for the future development of n-PBDF as a benchmark polymer for organic electronics and beyond.

Evidence for Trans-Oligoene Chain Formation in Graphene Induced by Iodine.

Functionalization of pristine graphene by hydrogen and fluorine is well studied, resulting in graphane and fluorographene structures. In contrast, functionalization of pristine graphene with iodine has not been reported. Here, the functionalization of graphene with iodine using photochemical activation is presented, which is thermally reversible at 400°C. Additional dispersive dominant Raman modes that are probed by resonance Raman spectroscopy are observed. Additionally, iodinated graphene is probed by Kelvin probe force microscopy and by transport measurements showing p-doping surpassing non-covalent iodine doping by charge transfer-complex formation. The emergent Raman modes combined with strong p-doping indicate that iodine functionalization is distinct from simple iodine doping. A reaction mechanism based on these findings is proposed, identifying the large size of iodine atoms as the probable cause governing regiochemically controlled addition due to steric hinderance of reactive sites. The modification of the electronic structure is explained by the confinement of 1D trans-oligoene chains between sp3 -defects. These results demonstrate the uniqueness of iodine reactivity toward graphene and the modification of the electronic structure of iodinated graphene, highlighting its dependence on the spatial arrangement of substituents.

Interfacial charge transfer complexes between ZnO and benzene derivatives: Characterization and photocatalytic hydrogen production

The interfacial charge transfer (ICT) complex formation is a simple procedure to bring optical absorption of wide-bandgap oxide materials in the visible spectral range, crucial for enhancing their use in photo-driven reactions. The optical absorption of the prepared ICT complexes between ZnO and five different colorless benzene derivatives is red-shifted compared to pristine ZnO nanopowder. The density functional theory (DFT) calculations provided realistic energy level alignment in hybrid systems. Also, the DFT-calculated infrared spectra support the binding structures derived based on experimental measurements of free and adsorbed ligands onto ZnO surfaces. The photocatalytic performance of prepared hybrids was evaluated using photocatalytic hydrogen generation in the water-splitting reaction. The ZnO nanopowders modified with catechol and caffeic acid have over 50% higher hydrogen production rate than pristine ZnO, displaying steady hydrogen production under long-run working conditions.

Controlled photoinduced electron transfer via triplet in polymer matrix using electrostatic interactions

Drawing inspiration from highly efficient natural photosynthetic systems, we developed an artificial photoinduced electron transfer (PET) system within a poly(N-methyl-4-vinylpyridinium) (P4VPMe) polymer matrix. This system features 5,10,15,20-tetrakis-(4-sulfonatophenyl) porphyrin (TPPS) and its zinc complex (ZnTPPS) as electron donors and methylviologen (MV2+) as the electron acceptor. In the presence of an excess of P4VPMe, ZnTPPS exists as individual molecules rather than self-aggregating, favoring PET. Under these conditions, P4VPMe inhibits the formation of ground-state charge-transfer complex between ZnTPPS and MV2+. This shifts the main PET process from singlet to triplet states. ZnTPPS in an excess of P4VPMe demonstrates over a tenfold increase in catalytic activity for the photoinduced oxidation of MV2+ compared to ZnTPPS alone.

Formation and characterization of charge transfer complex between alectinib and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone: Application to development of microwell spectrophotometric method

Alectinib (ALC) is a novel highly selective anaplastic lymphoma kinase (ALK) inhibitor that is effective in the treatment of patients with advanced ALK-positive non-small cell lung cancer and lymphomas. This study, describes, for the first time, the formation of a charge transfer complex (CTC) between ALC with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The CTC was characterized using different spectrophotometric and computational techniques. UV–visible spectrophotometry ascertained the formation of the CTC in methanol via the formation of a new broad absorption band with a maximum absorption peak (λmax) at 505 nm. The molar absorptivity (ε) of the complex was 2.72 × 103 L mol−1 cm−1 and its band gap energy was 1.94 eV. The stoichiometric ratio of ALC:DDQ was found to be 1:1. The association constant of the complex was 9.6 × 102 L mol−1, and its standard free energy was −16.98 J mol−1. Computational calculations were conducted using different calculation tools. The computed geometrical parameters, specifically bond lengths, exhibited variations in the CTC compared to the individual reactants (ALC and DDQ). The Mulliken atomic charge analysis indicated increased values for DDQ (the acceptor) and decreased values for ALC (the donor) in the CTC, confirming the formation of a CTC. The reaction was employed as a basis for a novel microwell spectrophotometric method for the quantification of ALC in its bulk form, capsule content, and uniformity testing. This greenness and high throughput of the method was documented. The method represents a valuable tool for routine use in quality control laboratories for analysis of ALC's bulk form and capsules.

Photoreactivity of polycyclic aromatic hydrocarbons (PAHs) and their mechanisms of phototoxicity against human immortalized keratinocytes (HaCaT)

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic compounds in the environment. They are produced by many anthropogenic sources of different origins and are known for their toxicity, carcinogenicity, and mutagenicity. Sixteen PAHs have been identified as Priority Pollutants by the US EPA, which are often associated with particulate matter, facilitating their dispersion through air and water. When human skin is exposed to PAHs, it might occur simultaneously with solar radiation, potentially leading to phototoxic effects. Phototoxic mechanisms involve the generation of singlet oxygen and reactive oxygen species, DNA damage under specific light wavelengths, and the formation of charge transfer complexes. Despite predictions of phototoxic properties for some PAHs, there remains a paucity of experimental data. This study examined the photoreactive and phototoxic properties of the 16 PAHs enlisted in the Priority Pollutants list. Examined PAHs efficiently photogenerated singlet oxygen and superoxide anion in simple solutions. Furthermore, singlet oxygen phosphorescence was detected in PAH-loaded HaCaT cells. Phototoxicity against human keratinocytes was evaluated using various assays. At 5 nM concentration, examined PAHs significantly reduced viability and mitochondrial membrane potential of HaCaT cells following the exposure to solar simulated light. Analyzed compounds induced a substantial peroxidation of cellular proteins after light treatment. The results revealed that a majority of the examined PAHs exhibited substantial reactive oxygen species photoproduction under UVA and violet-blue light, with their phototoxicity corresponding to their photoreactive properties. These findings improve our comprehension of the interactions between PAHs and human skin cells under environmental conditions, particularly when exposed to solar radiation.

Effect of SbCl5 Doping on the Electrical and Optical Properties of Polyamide Nylon 6 Films

Polyamide nylon 6 (PA6) films were fabricated using a solution casting method and the films were doped with SbCl5. The electrical conductivity increased with the dopant concentration due to the increase in formation of radical cations through the charge transfer from the isolated double bonds (–C=O–) in the polymer chains. The DC electrical conductivity reached a maximum of 0.01 S/cm for 0.5 ml SbCl5 doped films. Structural and optical characteristics of the pure and doped films were examined using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-Ray Diffraction (XRD), and Ultraviolet-Visible (UV-Vis) absorption spectra. The doped films exhibited discernible shifts in the optical band gap energy. The direct band gap values of PA6 films were reduced from 4.5 eV to 1.7 eV when doped with 0.5 ml SbCl5. ATR-FTIR spectral studies, and optical studies indicated the formation of charge transfer complexes with the amide group of nylon 6, resulting in the electrical conduction. The XRD studies disclosed the reduction in the crystallinity of the doped films. The thermal stability was studied using differential scanning calorimetry (DSC) and thermogravimetric analysis-derivative thermogravimetric (TGA-DTG) studies. The melting and crystallization temperatures were recorded from the DSC thermograms. The peak melting temperature of PA6 reduced from 217 °C to 186 °C for 0.5 ml SbCl5 doped films. The peak of crystallization observed at 182 °C for pure films was absent, for the doped samples. The peak degradation temperatures for both pure and doped samples were above 400 °C, revealing the thermal stability of both materials. The thermally stable, semi-crystalline and semiconducting polymer films, we suggest, would be suitable for optoelectronic applications.

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters.

Due to their ease of preparation, stability, and diverse reactivity, N-hydroxyphthalimide (NHPI) esters have found many applications as radical precursors. Mechanistically, NHPI esters undergo a reductive decarboxylative fragmentation to provide a substrate radical capable of engaging in diverse transformations. Their reduction via single-electron transfer (SET) can occur under thermal, photochemical, or electrochemical conditions and can be influenced by a number of factors, including the nature of the electron donor, the use of Brønsted and Lewis acids, and the possibility of forming charge-transfer complexes. Such versatility creates many opportunities to influence the reaction conditions, providing a number of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these reaction classes, we discuss the utility of the NHPI esters, with an eye towards their continued development in complexity-generating transformations.

An Appraisal for Providing Charge Transfer (CT) Through Synthetic Porous Frameworks for their Semiconductor Applications.

In recent years, there has been considerable focus on the development of charge transfer (CT) complex formation as a means to modify the band gaps of organic materials. In particular, CT complexes alternate layers of aromatic molecules with donor (D) and acceptor (A) properties to provide inherent electrical conductivity. In particular, the synthetic porous frameworks as attractive D-A components have been extensively studied in recent years in comparison to existing D-A materials. Therefore, in this work, the synthetic porous frameworks are classified into conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), and metal-organic frameworks (MOFs) and compare high-quality materials for CT in semiconductors. This work updates the overview of the above porous frameworks for CT, starting with their early history regarding their semiconductor applications, and lists CT concepts and selected key developments in their CT complexes and CT composites. In addition, the network formation methods and their functionalization are discussed to provide access to a variety of potential applications. Furthermore, several theoretical investigations, efficiency improvement techniques, and a discussion of the electrical conductivity of the porous frameworks are also highlighted. Finally, a perspective of synthetic porous framework studies on CT performance is provided along with some comparisons.

Charge transfer complex-based spectrophotometric analysis of famotidine in pure and pharmaceutical dosage forms

A straightforward and efficient spectrum technique was created using Ortho-chloranil as the electron acceptor (-acceptor) in a charge transfer (CT) complex formation reaction to determine the concentration of famotidine (FMD) in solutions. Compared to the double-distilled blank solution, the reaction result detected a definite violet colour at a maximum absorption wavelength of 546 nm, For concentrations range 2—28 µg/ml, the technique demonstrated excellent compliance with Beer-Law and Lambert's, as evidenced by its molar absorptivity of 2159.648 L mol−1 cm–1. Lower detection limits of 0.3024 µg/ml and 1.471 µg/ml, respectively, were discovered. The complexes of famotidine and Ortho-chloranil were found to have a 2:1 stoichiometry. Additionally, the suggested approach effectively estimated famotidine concentrations in pharmaceutical formulations, particularly in tablet form.

Charge-transfer inclusion complex formation of the tropylium cation with prism[6]arenes.

Herein, we report that prism[6]arenes (PrS[6]R) can form charge-transfer (CT) inclusion complexes with tropylium tetrakis[3,5-bis(trifluoromethyl)-phenyl]borate (G) in chloroform solution with an obvious CT band at 560 nm. Moreover, the CT complex PrS[6]Et⊃G showed Cl-/Ag+ responsiveness which can be easily monitored by the naked eye.

Spectrophotometric Determination of Atorvastatin Based on Charge Transfer Reaction with Quinalizarin

An easy and economical spectrophotometric method has been developed for the determination of atorvastatin from tablet formulation. This method is based on the formation of a blue-colored charge transfer complex of Atorvastatin with quinalizarin in methanol medium. The blue colored complex gives maximum absorbance at 573 nm. In order to develop the quantitative analysis method of atorvastatin, several parameters such as the type of solvent, the effect of reagent concentration, and the reaction time and temperature on absorbance of complex were investigated. It was determined that the optimum Quinz solution (0.5x10-³ M) was 3mL and the optimum temperature of the reaction was room temperature. Beer’s law range of proposed method is found 10-100 µg.mL-1. LOD and LOQ of the proposed method were found as 1.49 µg.mL-1 and 4.98 µg.mL-1, respectively. As a result, this proposed method can be used in the quantitative analysis of atorvastatin in tablet formulations

Regulation of photoinduced charge transfer in all-small-molecule organic solar cells through the synergistic effect of external electric field and solvent

The donor (BTR-Cl) and acceptor (BTP-FCl-FCl) have well-defined small molecule properties and excellent repeatability, and they can form charge transfer complexes with a wide spectral absorption range. Using density functional theory (DFT), we simulate the photoinduced charge transfer of bulk-heterojunction (BHJ) organic solar cell (OSC) materials modulated by the external electric field (Fext) at the microscopic level. The excited-state properties, reorganization energy (λ), Gibbs free energy (ΔG), electron coupling matrix elements (VDA) and intermolecular charge transfer (ICT) rate dependent on Fext are systematically analyzed. The results manifest that Fext has apparent positive regulation on the charge separation rate (KCS), and VDA is the main factor affecting KCS. The synergistic effect of solvent and Fext on charge transfer process is further investigated. It is found that the charge transfer rate in solvent is lower than that in solvent-free conditions, and the charge transfer rate in chlorobenzene (CB) solvent does not change significantly under the control of Fext. At the same time, Fext has a positive effect on the charge transfer rate in tetrahydrofuran (THF) solvent. Considering the charge transfer rate under different solvents and Fext intensities, it is found that the solvent and Fext play an essential role in determining the KCS and charge recombination rate (KCR).