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Bioelectronics concerns the integration of electronic elements with biological systems to form functional devices including biosensors for detection and analysis, neuroelectronic junctions, and biofuel cells for energy conversion and catalysis. A fundamental part of any bioelectronic system is the electronic coupling and transport at the various biotic/abiotic interfaces between biomaterials and electronic supports. The development and study of materials that modulate charge transport across these interfaces is therefore an area of interest. Advances in increasing the synergy between electronics and biology will see impacts in not only our understanding of system, cell, and molecular biology, but also more efficient electronics for conversion of bioenergy. In this development, we have focused on the implementation of redox-active conjugated electrolytes at the biotic/abiotic interface for amplifying biocurrent collection.In specifically-designed microbial bioelectrochemical systems, bacteria interface with electrodes to catalyze the interconversion of chemical and electrical energy. Membrane modifiers called conjugated oligoelectrolytes (COEs), defined by their conjugated core and peripheral ionic pendant groups, have been shown to increase the ability of electrogenic microbes to electronically communicate with abiotic components through a number of indirect factors including increasing electrode colonization and coulombic efficiency. However, precise control over the mechanism of current enhancement remained to be seen. Two ferrocene-containing COEs called DVFBO and F4-DVFBO were designed to test voltammetric control over biocatalytic current production. Both COEs have a π-delocalized core capped on each end by ferrocene units and show similar optical properties, affinity for the membrane, and toxicity, but fluorination of the core (F4-DVFBO) results in a higher redox potential (422 ± 5 mV compared to 365 ± 4 mV vs Ag/AgCl for DVFBO). The COEs were tested in anaerobic microbial three-electrode electrochemical cells (M3Cs) containing the model electrogenic bacterium Shewanella oneidensis MR-1. At a low electrode potential, the addition of the COEs produced negligible current enhancement compared to controls. However, at E = 365 mV, DVFBO increased steady-state biocurrent 67 ± 12% relative to controls while F4-DVFBO only increased biocurrent by 30 ± 5%. With no change in electrode colonization, cyclic voltammetry supports that DVFBO is the primary conduit of the increased catalytic current and shows F4-DVFBO has less activity at this poised potential. Overall, this work demonstrates the ability to modulate electron transfer from microbial species exclusively via the oxidation potential of the COE.While microbial membrane modification with redox-active COEs led to improvement in current extraction, a two-dimensional electrode structure limits the surface area for electroactive bacteria attachment and restricts efficient substrate and buffer diffusion. Conjugated polyelectrolytes represent a complementary interfacial materials strategy to enhance biotic/abiotic electronic coupling. First, the mixed ionic-electronic conduction properties of the self-doped conjugated polyelectrolyte CPE-K were investigated with respect to hydration. Films of CPE-K showed both increasing ionic and electronic conduction with hydration. Results indicate that the increase in electronic conduction was due to both increased number of free charge carriers and closer π-π stacking.Following this characterization, CPE-K was used as a conductive matrix to electronically connect a three-dimensional network of Shewanella oneidensis MR-1 to a gold electrode. At critical CPE-K concentrations, these biocomposites spontaneously assemble from solution into an intricate arrangement of cells within a conductive polymer matrix, thereby increasing biocurrent ~150-fold over control biofilms in M3C tests. While increased biocurrent is due to more cells in communication with the electrode, current extracted per cell is also enhanced indicating efficient long-range electron transport. Further, biocomposites show almost an order-of-magnitude lower charge transfer resistance than CPE-K alone, supporting that the electroactive bacteria and the conjugated polyelectrolyte work synergistically towards an effective electronic biocomposite. Examination of these biocomposites in microbial fuel cell configurations reinforces the need for continued pursuit of synthetic designs to improve the biotic/abiotic interface in bioelectronics.

Conductive fibers are an important part of wearable electronic devices or smart textiles while several grand challenges have to be still overcome. In this study, we describe a simple and efficient method to prepare a copper layer on nylon 6 fabrics by using a pH-responsive styrene (St)-co-N, N-dimethyl-dimethylaminoethyl methacrylate (DMAEMA)/Pd nanocomposite. The St-co-DMAEMA/Pd can effectively enhance the adhesion between the copper layer and the substrate. Nylon 6 fabric is treated with an optimal acid concentration of 2.0 M before electroless deposition. The pretreatment will promote the affinity between the nanocomposite catalyst and the modified nylon 6 fabric and form a more favorable environment for copper deposition. Furthermore, the process yields excellent copper deposition (1.59 μm) onto nylon 6 fabric after electroless plating for 20 min. The copper layer formed by the method has a low resistance of about 2.51 Ω and the variation of resistance before and after bending test is small. In addition, the characteristic of pH responsive copolymers (St-co-DMAEMA) that displays high hydrophilicity at low pH values and high hydrophobicity at high pH values is crucial for electroless copper plating. This facile method is successfully applied in the metallization of nylon 6 fabric.

Implantable bioelectrodes have the potential to advance neural sensing and muscle stimulation, mainly in patients with peripheral nerve injuries. They function as the transducer at the interface between the damaged nerve and the muscle which is controlled by that nerve. This work reports the fabrication and characterization of novel, low-cost, flexible bioelectrodes based on polyaniline (PANI) and supported with silicone polymer. The fabricated electrodes were evaluated for their electrical and mechanical characteristics. PANI was used as the main transducer component in this fabrication. The characterization methods included electrical conductivity, capacitive behavior, long-term electrical impedance, and mechanical evaluation. The results of the fabricated PANI-silicone-based samples displayed a bulk impedance of 0.6 kΩ with an impedance of 1.6 kΩ at the frequency of 1 kHz. Furthermore, the bioelectrodes showed a charge storage capacity range from 0.0730 to 4.3124 C/cm2. The samples were stable when subjected to cyclic voltammetry tests. The bioelectrodes revealed very flexible mechanical properties as observed from the value of Young’s modulus (in the order of MPa) which was less than that of skin. Hence, the PANI-based bioelectrodes reported herein showed promising electrochemical characteristics with high flexibility.

The third part of the review is devoted to polymer binders with electronic conductivity used to make composite electrodes for lithium electrochemical systems. Polymer semiconductors (“synthetic metals”), related polymers with additionally introduced functional groups, related copolymers and mixtures of polymers, as well as carbon chain polymers and copolymers with inсorporated polyaromatic fragments are considered. Such materials significantly improve electrical connectivity of the composite electrode and make it possible to eliminate or minimise the content of electrochemically inert conductive additives (carbon black, graphite powder), which positively influences on the specific capacity and cycling stability of the electrodes. Improving conditions of electronic transfer is especially important for the efficient use of active materials with extremely low intrinsic conductivity, such as Si, Li4Ti5O12, LiFePO4, etc. The final part of the review summarizes general principles of the targeted selection of a polymer binder.

Electrochemical polymerization of aniline by a combination of ultrasonic waves and electrolysis of water was performed. This method involves three processes: 1) creation of O2 micro bubbles produced by electrolysis of water on the anode side, 2) depolarization of the bubbles at the electrode surface via mechanical vibration using ultrasonic waves to diffuse ions in the electrolyte solution, and 3) progression of direct current (DC) electrochemical polymerization to yield a conductive polymer with fine pores on the surface. The diameter of the pores is on the micrometer scale and is similar in size to pollens. The combination of the electronic function of the conductive polymer and porous polymer surface can be applied as a method to collect allergens such as dust and flower pollens. Electrical adsorption and desorption of pollen was conducted with the porous polyaniline synthesized using a micro-bubble sonic-electrochemical preparation.

In the modern age, the most important and prevailing issue is the monitoring of human health. To address this, several devices have been developed and a need new materials investigated. The idea of textile-based smart sensors is emerging rapidly. In this regard, ICPs and ECPs have attracted the attention of researchers due to their mechanical adaptability to suit the characteristics of textile fabric. The lighter weight, stretchability and wearability, etc. are considered an advantage while selecting the material for developing sensors not only in health monitoring but also in biomedical, sports, and military fields. The idea behind wearable sensing devices is to enable easy integration of the sensor device into daily life routines. Such wearable sensors also have the potential for real time and online monitoring of human health and integrate with smart monitoring devices. The purpose of this review is to discuss the recent developments in smart monitoring sensors.

A graphene-based or carbon-based aerogel is a three-dimensional (3D) solid material in which the carbon atoms are arranged in a sheet-like nanostructure. In this study, we report the synthesis of low-density polymer-modified aerogel monoliths by 3D macro-assemblies of graphene oxide sheets that exhibit significant internal surface areas (982 m2/g) and high electrical conductivity (∼0.1 to 1 × 102 S/cm). Different types of materials were prepared to obtain a single monolithic solid starting from a suspension of single-layer graphene oxide (GO) sheets, and a polymer, made from the precursors 4-carboxybenzaldehyde and polyvinyl alcohol. These materials were used to cross-link the individual sheets by covalent bonds, resulting in wet-gels that were supercritically dried and then, in some cases, thermally reduced to yield graphene aerogel composites. The average densities were approaching 15-20 mg/cm3. This approach allowed for the modulation of distance between the sheets, pore dimension, surface area, and related properties. This specific GO/Polymer ratio has suitable malleability making it a viable candidate for use in conductivity 3D printing; it also has other properties suitable for energy storage, catalysis, sensing and biosensing applications, bioelectronics, and superconductors.

The practice of combining external stimulation therapy alongside stimuli-responsive bio-scaffolds has shown massive potential for tissue engineering applications. One promising example is the combination of electrical stimulation (ES) and electroactive scaffolds because ES could enhance cell adhesion and proliferation as well as modulating cellular specialization. Even though electroactive scaffolds have the potential to revolutionize the field of tissue engineering due to their ability to distribute ES directly to the target tissues, the development of effective electroactive scaffolds with specific properties remains a major issue in their practical uses. Conductive polymers (CPs) offer ease of modification that allows for tailoring the scaffold’s various properties, making them an attractive option for conductive component in electroactive scaffolds. This review provides an up-to-date narrative of the progress of CPs-based electroactive scaffolds and the challenge of their use in various tissue engineering applications from biomaterials perspectives. The general issues with CP-based scaffolds relevant to its application as electroactive scaffolds were discussed, followed by a more specific discussion in their applications for specific tissues, including bone, nerve, skin, skeletal muscle and cardiac muscle scaffolds. Furthermore, this review also highlighted the importance of the manufacturing process relative to the scaffold’s performance, with particular emphasis on additive manufacturing, and various strategies to overcome the CPs’ limitations in the development of electroactive scaffolds.

Bioelectricity plays an important role in cell behavior and tissue modulation, but is understudied in tissue engineering research. Endogenous electrical signaling arises from the transmembrane potential inherent to all cells and contributes to many cell behaviors, including migration, adhesion, proliferation, and differentiation. Electrical signals are also involved in tissue development and repair. Synthetic and natural conductive materials are under investigation for leveraging endogenous electrical signaling cues in tissue engineering applications due to their ability to direct cell differentiation, aid in maturing electroactive cell types, and promote tissue functionality. In this review, we provide a brief overview of bioelectricity and its impact on cell behavior, report recent literature using conductive materials for tissue engineering, and discuss opportunities within the field to improve experimental design when using conductive substrates.

Lithium-ion capacitors (LICs) have been proposed as an emerging technological innovation that integrates the advantages of lithium-ion batteries and supercapacitors. However, the high-power output of LICs still suffers from intractable challenges due to the sluggish reaction kinetics of battery-type anodes. Herein, polypyrrole-coated nitrogen and phosphorus co-doped hollow carbon nanospheres (NPHCS@PPy) were synthesized by a facile method and employed as anode materials for LICs. The unique hybrid architecture composed of porous hollow carbon nanospheres and PPy coating layer can expedite the mass/charge transport and enhance the structural stability during repetitive lithiation/delithiation process. The N and P dual doping plays a significant role on expanding the carbon layer spacing, enhancing electrode wettability, and increasing active sites for pseudocapacitive reactions. Benefiting from these merits, the NPHCS@PPy composite exhibits excellent lithium-storage performances including high rate capability and good cycling stability. Furthermore, a novel LIC device based on the NPHCS@PPy anode and the nitrogen-doped porous carbon cathode delivers a high energy density of 149 Wh kg−1 and a high power density of 22,500 W kg−1 as well as decent cycling stability with a capacity retention rate of 92% after 7,500 cycles. This work offers an applicable and alternative way for the development of high-performance LICs.

Currently, the challenge for bone tissue engineering is to design a scaffold that would mimic the structure and biological functions of the extracellular matrix and would be able to direct the appropriate response of cells through electrochemical signals, thus stimulate faster bone formation. The purpose of the presented research was to perform and evaluate PCL/n-HAp scaffolds locally modified with a conductive polymer-polyaniline. The material was obtained using electrospinning, and a simple ink-jet printing method was applied to receive the conductive polyaniline patterns on the surface of the electrospun materials. The samples of scaffolds were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal analysis (DSC, TGA), and infrared spectroscopy (FTIR) before and after immersion of the material in Simulated Body Fluid. The effect of PANI patterns on changes in the SBF mineralization process and cell morphology was evaluated in order to prove that the presented material enables the growth and proliferation of bone cells.

Electrical stimulation (ES) is a well-known method for guiding the behaviour of nerve cells in in vitro systems based on the response of these cells to an electric field. From this perspective, understanding how the electrochemical stimulus can be tuned for the design of a desired cell response is of great importance. Most biomedical studies propose the application of an electrical potential to cell culture arrays while examining the cell response regarding viability, morphology, and gene expression. Conversely, various studies failed to evaluate how the fine physicochemical properties of the materials used for cell culture influence the observed behaviours. Among the various materials used for culturing cells under ES, conductive polymers (CPs) are widely used either in pristine form or in addition to other polymers. CPs themselves do not possess the optimal surface for cell compatibility because of their hydrophobic nature, which leads to poor protein adhesion and, hence, poor bioactivity. Therefore, understanding how to tailor the chemical properties on the material surface will determine the obtention of improved ES platforms. Moreover, the structure of the material, either in a thin film or in porous electrospun scaffolds, also affects the biochemical response and needs to be considered. In this review, we examine how materials based on CPs influence cell behaviour under ES, and we compile the various ES setups and physicochemical properties that affect cell behaviour. This review concerns the culture of various cell types, such as neurons, fibroblasts, osteoblasts, and Schwann cells, and it also covers studies on stem cells prone to ES. To understand the mechanistic behaviour of these devices, we also examine studies presenting a more detailed biomolecular level of interaction. This review aims to guide the design of future ES setups regarding the influence of material properties and electrochemical conditions on the behaviour of in vitro cell studies.

International audience; Engineering of new heterogeneous metal-free catalysts is of great importance for persulfate activation. Herein, Innovative conductive polymers Polyaniline (PANI) and Polypyrrole (PPy) were used as promising catalysts for PS activation to effectively degrade organic pollutants. In fact, PANI and PPy can provide the necessary electron transfer based on nitrogen atoms located in the conjugated chains compared to their counterparts in the defective sites. In addition, PANI and PPy were immobilized inside membrane formed by cross linking alginate biopolymer by divalent calcium ions, in order to develop a new stable hydrogel beads catalyst. The prepared hydrogels-activated PS process could maintain excellent catalytic properties, mitigate catalysts deactivation, increased chemical stability and offer hope for their application in the industrial scale. The radical scavenging experiments monitored by the electron paramagnetic resonance and functional theory calculations, indicated the role of the PANI and PPy conjugated chains and the nature of the reaction pathways.

Sol–gel layers have been the subject of many studies in recent decades. However, very little information exists about layers in which carbon structures are developed in situ. Using the spin-coating method, we obtained thin iron-doped SiO2/C composite films. The results of Raman spectroscopy showed that our samples consisted of graphitic forms and polymers. The latter’s contribution decreases with rising temperature. FTIR and EDS studies show changes in carbon distribution on top of the layer, depending on the sintering temperature. The samples sintered at 800 °C showed a significant increase in the contribution of carbon forms to the layer’s surface. Therefore, high conductivity can be observed in this sample. The results of XPS spectroscopy showed that the contribution of sp3 hybridized carbon increases after etching. The total electrical conductivity, studied by a DC four-wire technique, increased with the temperature and showed almost linear characteristics with significant changes below 150 K. The reduced activation energy plot has a positive temperature coefficient, which is a characteristic property of the conductive polymers in a metallic regime of conductivity.

International audience; The demand for electronic devices that are flexible and wearable is growing. To facilitate this demand, the next generation devices must be able to bend and stretch under mechanical loading. In this regard, energy harvesting technologies have invested in organic and polymeric semiconducting materials due to their, low cost and toxicity, good flexibility, tunable electronic properties and capacity for scaled manufacturing. For example, electrically conductive π-conjugated polymers have been investigated in various thermoelectric technologies for producing stretchable, wearable, and light-weight thermoelectric devices that can harvest energy from a temperature gradient and produce electricity with no pollution or moving parts. This review provides a general summary of the thermoelectric principles and conductive polymer characteristics, followed by the recent progress in their application in flexible and wearable thermoelectric devices. We also evaluate new advances in manufacturing hybrids of π-conjugated polymers with other polymers, inorganic materials, or carbon nanostructures, and their applications in body energy harvesting and smart cooling.

Hypergolic systems rely on organic fuel and a powerful oxidizer that spontaneously ignites upon contact without any external ignition source. Although their main utilization pertains to rocket fuels and propellants, it is only recently that hypergolics has been established from our group as a new general method for the synthesis of different morphologies of carbon nanostructures depending on the hypergolic pair (organic fuel-oxidizer). In search of new pairs, the hypergolic mixture described here contains polyaniline as the organic source of carbon and fuming nitric acid as strong oxidizer. Specifically, the two reagents react rapidly and spontaneously upon contact at ambient conditions to afford carbon nanosheets. Further liquid-phase exfoliation of the nanosheets in dimethylformamide results in dispersed single layers exhibiting strong Tyndall effect. The method can be extended to other conductive polymers, such as polythiophene and polypyrrole, leading to the formation of different type carbon nanostructures (e.g., photolumincent carbon dots). Apart from being a new synthesis pathway towards carbon nanomaterials and a new type of reaction for conductive polymers, the present hypergolic pairs also provide a novel set of rocket bipropellants based on conductive polymers. Web of Science 26 6 art. no. 1595

The application of induced pluripotent stem cells (iPSCs) in disease modeling and regenerative medicine can be limited by the prolonged times required for functional human neuronal differentiation and traditional 2D culture techniques. Here, a conductive graphene scaffold (CGS) to modulate mechanical and electrical signals to promote human iPSC‐derived neurons is presented. The soft CGS with cortex‐like stiffness (≈3 kPa) and electrical stimulation (±800 mV/100 Hz for 1 h) incurs a fivefold improvement in the rate (14d) of generating iPSC‐derived neurons over some traditional protocols, with an increase in mature cellular markers and electrophysiological characteristics. Consistent with other culture conditions, it is found that the pro‐neurogenic effects of mechanical and electrical stimuli rely on RhoA/ROCK signaling and de novo ciliary neurotrophic factor (CNTF) production respectively. Thus, the CGS system creates a combined physical and continuously modifiable, electrical niche to efficiently and quickly generate iPSC‐derived neurons., Induced pluripotent stem cells are exciting cells for understanding development and in regenerative medicine. Stem cells respond to their environment to perform their functions and mature. A newly designed conductive scaffold is capable of shaping the mechanical and electrical environment. Utilizing this conductive polymer platform, enhanced stem cell neuronal maturation of the stem cells and important pathways can be identified.

For many years, the research on conjugated polymers (CPs) has been mainly focused on their application in organic electronics. Recent works, however, show that due to the unique optical and photophysical properties of CPs, such as high absorption in UV–Vis or even near-infrared (NIR) region and efficient intra-/intermolecular energy transfer, which can be relatively easily optimized, CPs can be considered as an effective light-activated source of versatile and highly reactive singlet oxygen for medical or catalytic use. The aim of this short review is to present the novel possibilities that lie dormant in those exceptional polymers with the extended system of π-conjugated bonds.

International audience; This study explores new chemical strategies for coating the hematite sand (HS) by conductive polymers to enhance the persulfate activation performance. The highest catalytic activity was due to synergistic effect between the HS and the conductive polymers. In fact, conjugated polymers could act as an activator and electronic mediator to promote the conversion of Fe (III) to Fe (II). Hence, both conductive polymers used (polyaniline and polypyrrole) have been found to provide the necessary electron transfer, thanks to their nitrogen atoms located in their conjugated chains. The radical scavenging experiments assessed by electronic paramagnetic resonance indicated that the studied pathways nature was both a radical and non-radical type. Further, it was found that the protective polymer layers prevented metal ion leaching, mitigate catalyst deactivation, enabled pH insensitive persulfate activation, and increased the chemical stability. This work provides a new innovative way to remove multiple pollutants in wastewater

In photocatalysis, small organic molecules are converted into desired products using light responsive materials, electromagnetic radiation, and electron mediators. Substitution of low molecular weight reagents with redox active functional materials may increase the utility of photocatalysis beyond organic synthesis and environmental applications. Guided by the general principles of photocatalysis, we design hybrid nanocomposites composed of n‐type semiconducting potassium poly(heptazine imide) (K‐PHI), and p‐type conducting poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the redox active substrate. Electrical conductivity of the hybrid nanocomposite, possessing optimal K‐PHI content, is reversibly modulated combining a series of external stimuli ranging from visible light under inert conditions and to dark conditions under an O2 atmosphere. Using a conductive polymer as the redox active substrate allows study of the photocatalytic processes mediated by semiconducting photocatalysts through electrical conductivity measurements., A conductive polymer (PEDOT:PSS) and potassium poly(heptazine imide) (K‐PHI) are combined in one hybrid nanocomposite as electron donor and photocatalyst, respectively. The composite represents an example of unconventional photocatalysis: K‐PHI modulates the physicochemical properties of the conductive polymer upon exposure to light and dark in different environments.

In this review, the unique properties of intrinsically conducting polymer (ICP) in biomedical engineering fields are summarized. Polythiophene and its valuable derivatives are known as potent materials that can broadly be applied in biosensors, DNA, and gene delivery applications. Moreover, this material plays a basic role in curing and promoting anti-HIV drugs. Some of the thiophene’s derivatives were chosen for different experiments and investigations to study their behavior and effects while binding with different materials and establishing new compounds. Many methods were considered for electrode coating and the conversion of thiophene to different monomers to improve their functions and to use them for a new generation of novel medical usages. It is believed that polythiophenes and their derivatives can be used in the future as a substitute for many old-fashioned ways of creating chemical biosensors polymeric materials and also drugs with lower side effects yet having a more effective response. It can be noted that syncing biochemistry with biomedical engineering will lead to a new generation of science, especially one that involves high-efficiency polymers. Therefore, since polythiophene can be customized with many derivatives, some of the novel combinations are covered in this review.

Electrically conductive hydrogels (ECHs), an emerging class of biomaterials, have garnered tremendous attention due to their potential for a wide variety of biomedical applications, from tissue-engineered scaffolds to smart bioelectronics. Along with the development of new hydrogel systems, 3D printing of such ECHs is one of the most advanced approaches towards rapid fabrication of future biomedical implants and devices with versatile designs and tuneable functionalities. In this review, an overview of the state-of-the-art 3D printed ECHs comprising conductive polymers (polythiophene, polyaniline and polypyrrole) and/or conductive fillers (graphene, MXenes and liquid metals) is provided, with an insight into mechanisms of electrical conductivity and design considerations for tuneable physiochemical properties and biocompatibility. Recent advances in the formulation of 3D printable bioinks and their practical applications are discussed; current challenges and limitations of 3D printing of ECHs are identified; new 3D printing-based hybrid methods for selective deposition and fabrication of controlled nanostructures are highlighted; and finally, future directions are proposed.

Recently, tissue engineering and regenerative medicine studies have evaluated smart biomaterials as implantable scaffolds and their interaction with cells for biomedical applications. Porous materials have been used in tissue engineering as synthetic extracellular matrices, promoting the attachment and migration of host cells to induce the in vitro regeneration of different tissues. Biomimetic 3D scaffold systems allow control over biophysical and biochemical cues, modulating the extracellular environment through mechanical, electrical, and biochemical stimulation of cells, driving their molecular reprogramming. In this review, first we outline the main advantages of using polysaccharides as raw materials for porous scaffolds, as well as the most common processing pathways to obtain the adequate textural properties, allowing the integration and attachment of cells. The second approach focuses on the tunable characteristics of the synthetic matrix, emphasizing the effect of their mechanical properties and the modification with conducting polymers in the cell response. The use and influence of polysaccharide-based porous materials as drug delivery systems for biochemical stimulation of cells is also described. Overall, engineered biomaterials are proposed as an effective strategy to improve in vitro tissue regeneration and future research directions of modified polysaccharide-based materials in the biomedical field are suggested.

Scanning Kelvin probe microscopy (SKPM), electrostatic force microscopy (EFM) are used to study the microscopic processes of the photo-induced charge separation at the interface of Ag and conductive polymers, i.e., poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b, 3,4-bʹ]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and poly(3-hexylthiophene-2,5-diyl) (P3HT). They are also widely used in order to directly observe the charge distribution and dynamic changes at the interfaces in nanostructures, owing to their high sensitivity. Using SKPM, it is proved that the charge of the photo-induced polymer PCPDTBT is transferred to Ag nanoparticles (NPs). The surface charge of the Ag-induced NPs is quantified while using EFM, and it is determined that the charge is injected into the polymer P3HT from the Ag NPs. We expect that this technology will provide guidance to facilitate the separation and transfer of the interfacial charges in the composite material systems and it will be applicable to various photovoltaic material systems.