Current Density-voltage Measurements Research Articles

Effects of the photoactive layer properties and current transmission mechanism on optical and electrical characteristics of organic photovoltaic

The P3HT:PCBM is an important organic material as an active layer for bulk heterojunction (BHJ) organic photovoltaics (OPVs). However, in terms of photophysical properties, blend ratios of both materials and device design is an important parameter for OPVs devices. In this study, the P3HT:PCBM photoactive layer, blended in different proportions by mass (1:1, 1:0.8, 1:0.6) was coated on the PEDOT:PSS surface using the spin coater method for different devices. Finally, Al have been evaporated on the photoactive layer and the device structure completed. In other examples, 2 nm lithium fluoride (LiF) as buffer layer evaporated on the active layer for each blending ratio before metal. Optical absorption, AFM, XRD, Raman and XPS measurements were taken for each active layer and it was observed that the surface morphology and absorption characteristic of the active layer changed according to the mixing ratios. This change in active layer properties directly affected the device parameters. Electrical characterization of the six different devices performed with current density-voltage (J–V) measurement and by used a solar simulator under 100 mW/cm2 irradiation intensity. Depending on the increase in short circuit current density (Jsc) and open current voltage (Voc) values in the devices, the power conversion efficiency (PCE) of the OPVs obtained varied between 0.86% and 2.74%. This change can be attributed to the fact that the P3HT:PCBM photoactive layer forms a smoother surface morphology depending on the PCBM ratio and the series resistance decreases. Another reason for this change in PCE can be explained by the effective electron injection of the LiF layer, LiF/Al layer with lower work function and less carrier deposition at its metal-active layer interfaces. It result has been obtained that the active layer with a ratio of 1:0.8 has a more homogeneous surface morphology and the series resistance decreases, the presence of the LiF layer in the device structures increases the Jsc and Voc, accordingly the PCE increases to 2.74%. These results showed that BHJ OPV with high PCE can be obtained with the ideal mixing ratio and appropriate device design.

Preparation and characterization of C:Se nano-rods ablated on porous silicon

In this work, Carbon:Selenium (C:Se) nanoparticles (NPs) are preparation by laser ablation at diverse laser energy 200, 400, 600,800 and 1000 mJ with 100 shots and laser wavelength 1064 nm then deposited on porous silicon (PS). PS are fabricated using electrochemical etching (ECE) method for p-type crystalline silicon (c-Si) wafers of (100) orientation.The pattern of X-ray diffraction (XRD) showed the sample's nanocrystaline.Results of the Atomic force microscope (AFM) analysis an average diameter of 39.76 nm coordinated in a rod-like shape appears for C:Se NPs. UV–vis result displayed that the optical energy gap of the nanoparticles increases. The electrical properties such as barrier height (ΦB) and ideality factor (n) of the Al/C:SeNPs/PS/Si/Al heterojunction were determined from the current density-voltage (J-V) measurements.

Stabilization of formamidinium lead triiodide α-phase with isopropylammonium chloride for perovskite solar cells

Formamidinium lead triiodide (FAPbI3) perovskite solar cells (PSCs) are mainly fabricated by sequentially coating lead iodide and formamidinium iodide, or by coating a solution in which all components are dissolved in one solvent (one-pot process). The PSCs produced by both processes exhibited similar efficiencies; however, their long-term stabilities were notably different. We concluded that the major reason for this behaviour is the stabilization of the α-FAPbI3 phase by isopropylammonium cations produced by the chemical reaction between isopropyl alcohol, used as solvent, and methylammonium chloride, added during the process. On this basis, we fabricated PSCs by adding isopropylammonium chloride to the perovskite precursor solution for the one-pot process and achieved a certified power conversion efficiency of 23.9%. Long-term operational current density–voltage measurements (one sweep every 84 min under 1-Sun irradiation in nitrogen atmosphere) showed that the as-fabricated device with an initial efficiency of approximately 20% recorded an efficiency of about 23% after 1,000 h that gradually degraded to about 22% after an additional 1,000 h. The operational stability of formamidinium lead triiodide solar cells varies with the fabrication method of the perovskite layer. Now Park et al. find that isopropylammonium stabilizes the perovskite structure and leads to solar cells with 2,000-h stability under constant illumination.

Effects of the PENTACENE as doping material on the power conversion efficiency of P3HT:PCBM based ternary organic solar cells

In organic solar cells (OSCs), changing the device geometry and the photophysical properties of the active layer is an effective way to change the power conversion efficiency (PCE). For this purpose, both the buffer layer was coated between the active layer and the metal and the organic material was doped to the active layer to obtain the ternary structure. In this study, for the fabrication of bulk-heterojunction (BHJ) organic solar cell, the PEDOT:PSS layer was coated on chemically cleaned ITO coated glass substrates by the spin coating method. Subsequently, the P3HT:PCBM blend as an active layer was coated on top of PEDOT:PSS in the glove box using the same method. Finally, aluminum (Al) was coated using thermal evaporation and ITO/PEDOT:PSS/P3HT:PCBM/Al organic solar cells structure as reference device were obtained. Then, PENTACENE material with an organic semiconductor property was doped into P3HT:PCBM blend and ITO/PEDOT:PSS/P3HT:PCBM:PENTACENE/Al bulk heterojunction organic solar cell structure was obtained using the same method. In addition, the effects of OSC on PCE were investigated by coating the 2 nm lithium fluoride layer between the Al and the active layer. For devices, dark and light current density-voltage (J-V) measurements were performed under 100 mW/cm2 in the glove box, and device parameters were calculated by the J-V curve. It was observed that the reference device showed photovoltaic properties under light and its PCE was 0.64%. When the experimental findings obtained were examined, both the LiF buffer layer and PENTACENE doping material improved the ternary OSC device performance and increased the PCE from 0.64% to 2.65%, according to the reference device. As a result of the doping, the mobility of the carrier increased with the increase of photon absorption and the presence of the buffer layer increased the carrier injection. Changing device properties can be explained with these results.

Towards significant enhancement of structural and optoelectronic properties of porphyrin palladium(II) complex: A theoretical and experimental analysis

In the present investigation, the nanostructure of porphyrin palladium(II) complex thin films was fabricated by low-cost conventional thermal analysis. The experimental and simulation investigations were used for the analysis of the structure and the unique optical characteristics for optoelectronic applications. The simulation processes using TD-DFT/ B3LYP were implemented to extract the distinguished geometry optimizations and other related parameters. The quantum theory of atoms in molecules (QTAIM) was additionally applied for the studied complexes to evaluate their peculiar electronic features. An indexation of XRD was performed to give a full identification of the crystal structure and supported by the results of transmission electron microscopy images. The investigation of the surface morphology and its quality for the optical applications was established using the atomic force microscopy, AFM supported surface topography mapping images. The optical properties confirm two main direct transitions with determined band gaps of 2.31 and 2.98 eV. The experimental optical gap was comparable with those theoretically extracted using DFT. The characteristics of the current density-voltage measurements verified rectification in the dark and under different values of illuminations. The device showed remarkable rectification characteristics with good responsitivity under illumination conditions. The maximum external quantum efficiency of 9.8% was obtained and compared to other organic-based devices.

A Combined Experimental and Computational Study of Chrysanthemin as a Pigment for Dye-Sensitized Solar Cells.

The theoretical study of chrysanthemin (cyanidin 3-glucoside) as a pigment for TiO2-based dye-sensitized solar cells (DSSCs) was performed with the GAUSSSIAN 09 simulation. The electronic spectra of neutral and anionic chrysanthemin molecules were calculated by density functional theory with B3LYP functional and DGDZVP basis set. A better energy level alignment was found for partially deprotonated molecules of chrysanthemin, with the excited photoelectron having enough energy in order to be transferred to the conduction band of TiO2 semiconductor in DSSCs. In addition, we used the raw aqueous extracts of roselle (Hibiscus sabdariffa) calyces as the source of chrysanthemin and the extracts with various pH values were tested in DSSCs. The extracts and photosensitized semiconductor layers were characterized by UV-Vis spectroscopy, and DSSCs based on raw extracts were characterized by current density-voltage measurements.

The Effects Of N-GaAs Substrate Orientations on The Electrical Performance of PANI/N-GaAs Hybrid Solar Cell Devices

This paper reports the fabrication and electrical characterization of hybrid organic-inorganic solar cell based on the deposition of polyaniline (PANI) on n-type GaAs substrate with three different crystal orientations namely Au/PANI/(100) n-GaAs/(Ni-Au), Au/PANI/(110) n-GaAs/(Ni-Au), and Au/PANI/(311)B n-GaAs/(Ni-Au) using spin coating technique. The effect of crystallographic orientation of n-GaAs on solar cell efficiency of the hybrid solar cell devices has been studied utilizing current density-voltage (J-V) measurements under illumination conditions. Additionally, the influence of planes of n-GaAs on the diode parameters of the same devices has been investigated by employing current-voltage (I-V) characteristics in the dark conditions at room temperature. The experimental observations showed that the best performance was obtained for solar cells fabricated with the structure of Au/PANI/(311)B n-GaAs/(Ni-Au). The open-circuit voltage (Voc), short circuit current density (Jsc), and solar cell efficiency () of the same device were shown the values of 342 mV, 0.294 mAcm-2, 0.0196%, respectively under illuminated condition. All the solar cell characteristics were carried out under standard AM 1.5 at room temperature. Also, diode parameters of PANI/(311)B n-GaAs heterostructures were calculated from the dark I-V measurements revealed the lower reverse saturation current (Io) of 3.0×10-9A, higher barrier height () of 0.79 eV and lower ideality factor (n) of 3.16.

Hysteresis Analysis of Hole-Transport-Material-Free Monolithic Perovskite Solar Cells with Carbon Counter Electrode by Current Density-Voltage and Impedance Spectra Measurements.

Due to the tremendous increase in power conversion efficiency (PCE) of organic–inorganic perovskite solar cells (PSCs), this technology has attracted much attention. Despite being the fastest-growing photovoltaic technology to date, bottlenecks such as current density–voltage (J–V) hysteresis have significantly limited further development. Current density measurements performed with different sweep scan speeds exhibit hysteresis and the photovoltaic parameters extracted from the current density–voltage measurements for both scan directions become questionable. A current density–voltage measurement protocol needs to be established which can be used to achieve reproducible results and to compare devices made in different laboratories. In this work, we report a hysteresis analysis of a hole-transport-material-free (HTM-free) carbon-counter-electrode-based PSC conducted by current density–voltage and impedance spectra measurements. The effect of sweep scan direction and time delay was examined on the J–V characteristics of the device. The hysteresis was observed to be strongly sweep scan direction and time delay dependent and decreased as the delay increased. The J–V analysis conducted in the reverse sweep scan direction at a lower sweep time delay of 0.2 s revealed very large increases in the short circuit current density and the power conversion efficiency of 57.7% and 56.1%, respectively, compared with the values obtained during the forward scan under the same conditions. Impedance spectroscopy (IS) investigations were carried out and the effects of sweep scan speed, time delay, and frequency were analyzed. The hysteresis was observed to be strongly sweep scan direction, sweep time delay, and frequency dependent. The correlation between J–V and IS data is provided. The wealth of photovoltaic and impendence spectroscopic data reported in this work on the hysteresis study of the HTM-free PSC may help in establishing a current density–voltage measurement protocol, identifying components and interfaces causing the hysteresis, and modeling of PSCs, eventually benefiting device performance and long-term stability.

Mg-doped ZnO layer to enhance electron transporting for PbS quantum dot solar cells

In this work, the effect of Mg doping on the performance of PbS quantum dot (QD) solar cells (QDSCs) is investigated. To elucidate that, PbS QDSCs with pristine ZnO and Mg-doped ZnO (ZMO) as electron transporting layers (ETLs) are fabricated, respectively. The current density-voltage (J-V) measurements are performed. The results show that the cell efficiency of the device with ZMO as an ETL is 9.46%, which increases about 75% compared to that of the pristine ZnO based device (5.41%). Enhanced short current density (Jsc) and fill factor (FF) are observed. It is demonstrated that Mg doping could passivate the surface defects and suppress the carrier recombination in ZnO ETL, thus resulting in larger bandgap and higher Fermi level (EF). The strategy of Mg-doped ZnO ETL provides a promising way for pushing solar cell performance to a high level.

Enhanced solar-cell efficiency via fabricated zinc sulfide nanocrystalline thin film-based Schottky diodes as a bypass: An experimental and theoretical investigations

This work represents experimental and theoretical investigations on the electrical characteristics of ZnS nanocrystalline thin films synthesized via sonicated (UCBD) and un-sonicated (CBD) chemical bath deposition technique and the fabrication of Schottky junction diodes, for potential solar cell incorporation and other opto-electronic applications. The sonication induced ZnS nanocrystalline thin films (SNP) at frequency 20 kHz–1 MHz and without sonication induced ZnS nanocrystalline thin films (NP) deposited on an indium tin oxide (ITO) substrate. A rapid thermally evaporated lightly doped Ag on SNP and NP-ZnS transparent thin films in the high range of vacuum (~10−6 Torr), has been achieved. The current density-voltage (J-V) and capacitance-voltage (C-V) measurements of fabricated Schottky diodes were carried out employing a potentiostat device. The enhanced performance of fabricated Schottky devices has been quantified by analyzing their J-V characteristics using established Landauer transport formalism. Ideal diode behavior has been confirmed by a low voltage drop of 0.35 V, and low junction capacitance ~3.21 nF across fabricated Schottky diodes. The maximum blockage of leakage current across fabricated Schottky diodes have been detected as compared to the available commercial diodes. The Landauer transport model found to be excellent fitting for understanding the electron transport mechanism for these fabricated diodes. The Fermi energy level pinned near effective gap center that shifts under the bias condition due to the metal induced gap states. The Schottky diodes as a bypass in solar cell panel demonstrates the significant enhancement in photo-response and efficiency of solar cell in the presence of sunlight.

The influence of various concentrations of ammonia on titania properties as a photo-anode for dye-sensitized solar cell

The amorphous TiO2 samples have been prepared by a combination of sol–gel and solvothermal processes with different concentrations of ammonia. The mesoporous TiO2 samples with polycrystalline tetragonal anatase crystal structure were obtained upon calcination at about 500 °C for 2 h. The structural, optical, morphological, and optoelectronic properties were studied by using X-ray diffraction (XRD), Raman spectroscopy, UV–Vis spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller (BET) analysis, and Scanning electron microscopy. The illuminated current density–voltage measurements were performed to measure the solar cell performance. The band gap values ~ 3.28 eV with variation ± 0.03 eV were estimated from optical absorption with a small variation in the slope of Tauc curves. The dye loaded in TiO2 mesoporous layer prepared without ammonia revealed better absorption for overall UV and visible region probably due to the presence of large voids on the surface of sample. The maximum efficiency in the present work of ~ 2.05% is measured for the dye-sensitized solar cell (DSSC) prepared with N3 (cis-bis (isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato ruthenium(II)) dye. The large surface area and voids present in mesoporous TiO2 layer obtained without ammonia may be suitable to produce high-efficiency DSSC devices.

Role of the Au and Ag nanoparticles on organic solar cells based on P3HT:PCBM active layer

In this article, P3HT:PCBM blend active layer was incorporated with Au and Ag nanoparticles (NPs) for different concentration to investigate the effects of the NPs on the performance organic solar cells (OSCs) with ITO/PEDOT:PSS/P3HT:PCBM:NPs/LiF/Al design. The active layer was analyzed by AFM, SEM and XRD measurements. Optical energy gap of P3HT:PCBM (undoped) and P3HT:PCBM (doped) active layers were obtained using UV–visible spectroscopy for different concentrations. The photovoltaic current density–voltage measurements were carried out under air mass (AM) 1.5G solar simulation. The OSC whose active layer undoped, gave the Jsc of 17.09 mA/cm2, Voc of 0.48 V, FF of 45%, and PCE of 2.11%. Whereas, the highest values of PCE were calculated as 3.11% for doped with Au NPs (1.5 wt%) and as 3.20% for Ag NPs (0.5 wt%), respectively. In summary, Au and Ag NPs created strong local electric field enhancements and caused to a surface plasmonic effect in the active layer for some concentrations and improved the device’s PCE.

Effect of doped polyaniline/graphene oxide ratio as a hole transport layer on the performance of perovskite solar cell

Perovskite solar cells (PSCs) are believed to be one of a promising choice of the third-generation technology platforms to address the increasing green energy demands. The main objective of this work is to fabricate a hole transport layer (HTL) based on doped polyaniline (PANI) and graphene oxide with different ratios. This layer was characterized using Raman spectroscopy, scanning electron microscope (SEM), atomic force microscopy (AFM), UV–Visible spectroscopy, photoluminescence, contact angle, Hall effect and current density–voltage measurements. Photoluminescence confirmed that the HTL of PANI/GO with 1:0.5 ratio had the highest efficiency to extract hole carriers. The conductivity and carrier concentrations of this layer were increased with the addition of small amounts of GO up to 1:0.5 and declined at the high ratio of 1:1. The optimal performance of the fabricated inverted PSC using HTL of PANI/GO with 1:0.5 ratio had short-current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency of 21.23 mA/cm2, 0.52 V, 0.67 and 9.24%, respectively.

The effect of current density–voltage measurement conditions on the operational stability of hybrid perovskite solar cells

Organic–inorganic lead halide perovskites have attracted great attention for use in solar cells, because of their efficient solar power conversion, along with compatibility with simple solution processing. To evaluate the operational stability of perovskite solar cells (PSCs), measurements on their current density–voltage (J−V) curves are periodically repeated in most literature studies. However, how the periodic J–V measurements affect the operational stability of PSCs has not been well understood to date. In this study, we found that repeating the J−V measurements, especially applying a voltage higher than the open-circuit voltage of PSCs, under continuous illumination, causes serious ion migration, which lowers the operational stability of PSCs. On the other hand, we observed no decrease in operational stability when the applied voltage is close to or lower than the open-circuit voltage of PSCs during the periodic J−V measurements because of the suppressed ion migration. These findings are important in evaluating the intrinsic operational stability of PSCs.

Wide-low energy coupled semi-conductor layers of TiO2 – CdX boosting the performance of DSSC

This investigation involves design and fabrication of CdSe overlayer on titania substrate that produces a highly functional DSSC (dye sensitized solar cell) anode using commercial N3 as the sensitizer dye. CdSe nanoparticles were deposited on TiO2 through periodic voltammetry under variable (10 – 130) cycle scans. Matrix morphology and optical parameters of the TiO2 – CdSe fabricated layer were respectively determined by electron microscopy and UV–Visible spectroscopy. Output performance of the cell under illumination was recorded by current density–voltage measurements, transient photo response, electrochemical impedance spectroscopy and incident photon to current conversion efficiency, while chrono-amperometry was used to derive durability of the cell. Remarkable output parameters were obtained for the optimized CdSe – TiO2 photo-anode loaded under 70 cycles showing, 13.29% photo conversion efficiency (PCE) and 15.30 mA cm−2 short circuit current density (JSC) for the operating DSSC. Similar investigations were extended to other chalcogenide NPs (CdTe and CdS) embedded on TiO2 for comparative study, whereby CdSe – TiO2 system was identified as the best performing DSSC anode matrix facilitating electron injection by the concerted effort of aligned energy band levels.

Investigation of praseodymium and samarium co-doped ceria as an anode catalyst for DIR-SOFC fueled by biogas

The Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer.The XRD, SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore, the electrical properties of SOFCs with catalytic layers deposited on the Ni-YSZ anode were examined by a current density-time and current density-voltage dependence measurements in hydrogen (24 h) and biogas (90 h). Composition of the outlet gasses was in situ analysed by the FTIR-based unit.It has been found out that Ce0.9Sm0.1O2-δ and Ce0.8Pr0.05Sm0.15O2-δ catalytic layers show the highest stability over time and thus are the most attractive candidates as catalytic materials, in comparison with other investigated lanthanide-doped ceria, enhancing direct internal reforming of biogas in SOFCs.

P3HT: PCBM Tabanlı Organik Güneş Hücrelerinin Opteoelektronik Özelliklerinin Aktif Katman Kalınlığına Bağlı İncelenmesi

This paper presents the production and results of optoelectronic characterization process for ITO/PEDOT:PSS/P3HT:PCBM/Al organic solar cells (OSC). OSCs were produced in open air environment with various P3HT:PCBM active layer thicknesses of 70, 110, 140, 175 and 190 nm. The diode properties of the solar cells in the dark have been investigated by using current-voltage (I-V) measurements. The absorption characteristics have been investigated by using transmission spectroscopy, and optical band gap energy (Eg) for each sample has been calculated. Solar cell parameters for each solar cell has been investigated by using current density-voltage (J-V) measurements under AM 1.5 solar raditation, and important solar cell parameters have been calculated. It was observed that fill factor (FF) value of the solar cells increase between 0.3239 and 0.3409 with decreasing diode ideality factor (n) value. The highest value of PCE was found to be 0.59, which belongs to the cell having 140 nm P3HT:PCBM thickness.

Structural Optimization and Temperature-Dependent Electrical Characterization of GaAs Single-Junction Solar Cells

This paper reports the structural optimization and the temperature-dependent electrical characterization of GaAs single-junction solar cells (SJSCs) based on the p+-n-n+ junction structure. First, the effects of the p+-Al0.9Ga0.1As window layer were investigated using illuminated current density-voltage (LJ−V) and photoreflectance measurements to determine the optimal structure of the SJSC. In addition, the thickness and the doping concentration of different layers, such as the p+-GaAs emitter and the n-GaAs base layers, were optimized, leading to the maximum efficiency (η = 21.53%). These results show that the device performance can be improved further when compared to the world record (η = 28.8%). Second, the capacitance-voltage (C−V) and the dark J−V characteristics of a GaAs SJSC with the optimal structure were investigated over the temperature range from 100 to 300 K. As the temperature was increased, both the junction capacitance at zero voltage (Cj0) and the carrier concentration in the active region (Nd) increased while the depletion width (W) and the built-in potential (Vbi) decreased due to purely thermal effects. Among the SC parameters obtained from the dark J−V curves, the ideality factor (n) decreased from 4.38 to 1.70 and the reverse saturation current density (J0) increased from 6.05 × 10 −12 to 4.26 × 10 −10 A/cm2 with increasing temperature. These values at 300 K were similar to those simulated theoretically and reported previously for high-quality GaAs junction diodes.

The role of metastability and concentration on the performance of CIGS solar cells under Low-Intensity-Low-Temperature conditions

Commercially available lightweight-flexible CIGS solar cells are investigated under the Low-Intensity-Low-Temperature (LILT) conditions that exist at Mars, Jupiter, and Saturn. Current density-voltage measurements, concentrated solar, and external quantum efficiency measurements are performed under varying temperatures and illumination intensities to determine the applicability and performance of flexible CIGS in outer planetary conditions. The well-known metastability of the CIGS absorber is observed as a result of a barrier to minority carrier extraction at the CIGS/CdS interface under higher intensity illumination. However, despite the low temperatures and low intensities experienced in deeper space, the presence of this barrier does not significantly affect the performance of the solar cells under LILT conditions. This is attributed to the lower photogeneration rate of carriers particularly at conditions relative to Saturn and Jupiter, which appears to be less than the thermionic emission rate across the barrier and therefore the carrier extraction is relatively unaffected under these illumination conditions. At elevated temperatures and/or intensities such as at AM0 and conditions relative to Mars, however, the higher carrier generation rate results in the appearance of large series resistance and a significant loss of fill factor at irradiation levels greater than 1-sun AM0. Proton irradiation of the solar cells systematically reduces the performance, predominately through the formation of defect states in the absorber layer, the presence of which is increasingly more prohibitive in LILT conditions due to the low thermal energy of the minority carriers and the subsequent increased effect of SRH recombination.

Synthesis of polyaniline/electrochemically exfoliated graphene composite as counter-electrode in dye-sensitized solar cell

ABSTRACT Polyaniline (PANI)/graphene composite is a good candidate for the counter-electrode in a Pt-free DSSC. In this study, the electrochemically exfoliated graphene (EEG) from the used-battery graphite rod was produced. DC measurement reveals that EEG has a relatively low sheet resistance of 502.72 Ω/square. EEG suspension in DMF was used as synthesis media of PANI/EEG composite using the direct mixing method. Raman spectra show that the PANI/EEG composite was successfully synthesized as indicated by the presence of their characteristic peaks. Current density-voltage (J-V) measurements show that the power conversion efficiency of PANI/EEG composite better than the PANI-based counter-electrode.