Organic Electrochemical Rectifiers (OECRs), derived from Organic Electrochemical Transistors, are promising components for flexible electronics and bioelectronic circuits due to their tunable rectifying behavior. In this study, we investigate the effect of gate electrode material on the rectification performance of OECRs using platinum (Pt), silver (Ag), and copper (Cu) gates. Our results reveal that the gate electrode potential, established through electric double layer formation at the gate/electrolyte interface, significantly influences channel conductivity and sets the intrinsic potential difference between the OECR terminals. Devices with Pt and Ag gates exhibit clear diode-like rectification, while the Cu-gated device displays non-diode-like behavior. Spectro-electrochemical measurements and electrochemical impedance spectroscopy confirm that negative gate electrode potentials (Ag and Cu) induce hole depletion in the channel. Open-circuit potential measurements further reveal a nonlinear potential profile along the channel in the absence of external bias. These findings demonstrate that the intrinsic gate potential is a critical design parameter that governs electrochemical doping, potential distribution, and the overall rectification characteristics of OECRs.

In this work, the influence of laser-ablated tungsten disulfide (WS2) nanoparticles on the morphological, optical, and electrical properties of PEDOT:PSS thin films is systematically investigated. WS2 nanoparticles with an average diameter of 36 nm were synthesized by laser ablation in liquid and incorporated into the PEDOT:PSS matrix via solution blending followed by spin coating. Atomic force microscopy revealed a concentration-dependent modification of surface morphology, with the average roughness increasing from 0.84 nm for pristine PEDOT:PSS to 1.64 nm at a WS2 content of 10

This study demonstrates that the use of bilayer films based on nickel oxide (NiOx;) and cobalt phthalocyanine (CoPc) represents a promising hole transport layer (HTLs) for inverted perovskite solar cells (PSCs). NiOx; films are fabricated using the spin-coating method from a sol-gel solution. Films (CoPcevap) and nanowires (CoPcnws) on the NiOx; surface are produced by thermal sputtering and physical gradient-temperature vapor deposition. It is demonstrated that PSCs with a NiOx; layer exhibit a power conversion efficiency (PCE) of only 18,1%. The incorporation of a CoPcevap intermediate layer between NiOx; and the perovskite increases the PCE to 19.1%. The highest PCE, reaching 20.7%, is achieved with a bilayer HTLs based on NiOx;/CoPcnws. Analysis of the PSC impedance spectra shows that the CoPcnws intermediate layer reduces the HTLs resistance and increases the recombination resistance at the perovskite/HTLs interface, which extends the effective lifetime of charge carriers. The stability of NiOx;-based PSCs is 48%, while PSCs with bilayer HTLs based on NiOx;/CoPcnws and NiOx;/CoPcevap exhibits higher stability of 71% and 90% over 600 hours. The results demonstrated that solar cells based on NiOx;/CoPc inhibit the perovskite degradation process and reduce charge recombination, thereby improving the performance and stability of the inverted PSCs.

Perovskite solar cells (PSCs) have emerged as a leading technology in the photovoltaic sector due to their high efficiency and low fabrication cost. However, the performance and stability of PSCs are often limited by the properties of hole transport layers (HTLs). In this study, we explore the use of cobalt phthalocyanine (CoPc) and a composite CoPc/Spiro-OMeTAD layer as HTLs to enhance the efficiency and stability of PSCs. Structural analysis via AFM revealed that the CoPc/Spiro-OMeTAD composite layer possesses a uniform, pinhole-free surface morphology, crucial for minimizing charge recombination. Optical studies demonstrated that these composite layers maintain high transparency while providing effective light absorption. Photoelectrical characterizations showed that PSCs with the CoPc/Spiro-OMeTAD HTLs achieved a power conversion efficiency (PCE) of 18.7 %, outperforming devices with standard Spiro-OMeTAD and single CoPc layers. Moreover, the composite HTLs improved the stability of the PSCs, retaining 84 % of the initial PCE after 300 hours of operation without encapsulation. Impedance spectroscopy indicated that the composite HTLs reduce series resistance and charge transfer resistance of the devices. These findings suggest that CoPc/Spiro-OMeTAD composite layers are promising candidates for enhancing both the efficiency and stability of PSCs.

Organic solar cells (OSCs) are promising candidates for next-generation photovoltaics due to their lightweight, mechanical flexibility, and compatibility with low-cost, large-area fabrication. However, their commercial application remains limited by low charge carrier mobility and high recombination rates. In this study, we investigated the role of tungsten diselenide (WSe2) nanoparticles (NPs) in enhancing the charge transport and suppressing recombination in P3HT:PC61BM-based polymer solar cells. WSe2 NPs, synthesized via laser ablation in chlorobenzene, were incorporated into the bulk heterojunction (BHJ) active layer. Structural, optical, and electrical characterizations were performed using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Ultraviolet – visible (UV–Vis), Photoluminescence (PL), Raman, and impedance spectroscopy. At the optimized concentration of 0.35 wt.

This approach allows you to more accurately evaluate the performance of solar panels and identify any prob- lems or degradation in their operation. The LUMO value of mPc closer to the LUMO value of CH3NH3I3PbClx increased conversion energy and short circuit current density (Jsc), which reached a maximum value of 15.97 mA/cm² using the HTL layer of CuPc, and the open circuit voltage (Voc) reached a maximum at 0.97 V. The change in Jsc corresponds to the fill factor (FF) change. The filling factor (FF) reached a maximum value of 67.35 % when using the HTL layer of CuPc and a minimum value (FF) of 54.23 % when using the HTL layer of H2Pc. The lowest series resistance (R1) and interface resistance (R3) of 11.2 and 39.9 Ohms, respectively, were shown with the HTL layer of CuPc, Capacitive element CPE1 — 305 pF, Capacitive element CPE2 — 0.95 pF. CPE (Constant Phase Element) is an element used in equivalent circuits to describe the non-ideal dielectric properties of materials. The decrease in CPE1 may indicate a decrease in the heterogeneity of the dielectric properties of the perovskite material after coating with different HTL mPc layers. This may be due to changes in structure or mutual actions between layers as a result of exposure to differences in energy levels.

The deposition of ZnO thin films using sol-gel technology is a straight forward and widely used method for fabricating ZnO films with diverse morphologies and tunable electrical and optical properties. Notably, the preparation of ZnO compact layers from a zinc acetate and monoethanolamine (ZA:MEA) solution via spin-coating has gained popularity due to its simplicity. The pretreatment of spin-coated ZA:MEA films significantly impacts the morphology and structure of the resulting ZnO films. While the effects of preheating and its rate on ZnO precursor films have been extensively studied, the morphological and structural evolution of ZA:MEA films immediately after spin-coating and its subsequent impact on the final ZnO film have not been previously explored. In this study, we present the topography and phase composition of as-grown ZA:MEA films using atomic force microscopy (AFM). We conduct an in-situ investigation of the morphological evolution of ZA:MEA films. Our results reveal that as-grown ZA:MEA films possess an inhomogeneous structure. AFM phase image shows two distinct domains in the ZA:MEA films. Over time, we observe the growth of crystals in both vertical and perpendicular directions. ZA:MEA film aged for at least 20 h develops arrays of vertically oriented crystals throughout the film covered with sheet-like crystals forming on the film surface. This temporal evolution in the morphology and structure of ZA:MEA films significantly influences the morphology of the final ZnO film.

For inverted organic solar cells (IOSC), the interface contacts between the ZnO electron transport layer and the organic active layer play an important role in device performance and stability. The light absorption effect is one of the major disadvantages of IOSC when metal oxides are used as the electron transport layer (ETL). Oxide ETL primarily causes the above effect due to the energy barrier, deep level defects and excess carrier tunneling. In this work, we studied the effects of annealing ZnO films under various environmental conditions. ZnO films were synthesized by the sol-gel method, and the films were annealed at a temperature of 450 degrees C in air, an inert nitrogen gas (N-2), oxygen (& Ocy;(2)) and vacuum. SEM images and EDX spectra of the surface of thin ZnO films showed a change in thickness and the quantitative content of Zn/O elements. It was found that the annealing environment has a great influence on the morphology and thickness of ZnO films. Numerical calculations of the extinction, absorption, and scattering spectra of ZnO nanoparticles of different sizes are in good agreement with the results of measurements. Volt-ampere and electrical impedance measurements showed that ZnO films not only change the overall electrical resistance of devices to the contribution of the ZnO film resistance, but also change the electrical properties of the P3HT-PC61BM heterojunction.

In this paper, we studied the effects of the annealing temperature of nickel oxide (NiO x ) thin films on the structural, optical, and electrical transport properties. Thin NiO x was synthesized by the sol-gel method, followed by annealing at different temperatures varying from 200 to 450 degrees C. From the obtained AFM image data, an increase in the surface Ra value is observed with rising film annealing temperature. The decrease in film thickness with increasing annealing temperature is associated with significant densification of NiO x . During thermal annealing, a change in the redistribution of Ni/O elements is seen in the films. The increase in the intensity of the (1P)LO scattering peak in NiO x with rising annealing temperature is associated with a growth in the density of defects due to Ni vacancies. When the annealing temperature reaches 250 degrees C, an increase in Eg = 3.49 eV is detected; a further rise of the annealing temperature leads to a decrease in Eg = 2.92 eV. The increase in the index n of films with rising annealing temperature is associated with the formation of a denser and more ordered NiO x film. A rise in the annealing temperature of NiO x films leads to an increase in the value of the total resistance of the films, a decrease in the resistance of hole recombination at the NiO x /electrode interface, and the value of the conditional mobility of holes.

The influence of the annealing medium of thin films of nickel oxide (NiOx) on structural, optical and electrical transport properties is studied in this paper. NiOx films were synthesized by sol-gel method and annealed at a temperature of 300 degrees C in air, inert nitrogen (N2), oxygen (O2) gases and vacuum. The values of the films thickness were determined from the transverse cleavage of the SEM image. The films thickness depends on the annealing medium. Measurements of the EDX spectra of NiOx films were carried out. Analysis of the quantitative O/Ni ratio showed that the film annealed in an air atmosphere is close to the stoichiometric parameters of NiO. Measurements of the EDX spectra of NiOx films were carried out. According to the Raman spectra, an increase in peak intensities is observed indicating an increase in the density of defects in the film by Ni vacancies depending on the annealing medium. Absorption spectra and Tauc plots of NiO & khcy; films were obtained. The optical density of the films depends on the annealing conditions of the films. Data analysis shows that the band gap width depends on the annealing medium and varies from Eg = 3.12 eV to Eg = 3.45 eV. The analysis of the impedance spectra allowed us to estimate the values of the resistances R1 and R2. It is shown that an increase in the resistance of R1 is associated with a decrease in the density of defects in the NiOx film, decrease in the recombination resistance of R2, and an increase in recombination processes at the interface.

The paper presents the results of a study of the structural, optical and electrophysical characteristics of phthalocyanine films and its metal complexes with different thicknesses. Films of phthalocyanine and its metal complexes were obtained on the conductive surface of the FTO by thermal evaporation in vacuum. It is shown that the observed broadening of the B and Q bands and the hypsochromic shift of the maxima in the absorption spectra are associated with the central atom. With a decrease in the thickness of MPc films, there is a decrease in the value of the half-width of the absorption spectra. The effect of the thickness of phthalocyanine films on the efficiency of generation and transport of charge carriers in the FTO/MPc/Al cell was studied. It is shown that the VAC increases almost 2.5 times compared to a photocell based on a metal-free phthalocyanine. From the obtained impedance measurement data, it was found that the electrophysical parameters of phthalocyanines depend on the values of optical density, broadening of absorption bands in the short-wave and visible spectral regions, which is consistent with the data of the volt-ampere characteristic.

PEDOT:PSS is one of the most widely used materials as a hole selective layer in organic photovoltaics due to its easy processing and high reproducibility. Unfortunately, the material is limited when testing new donor:acceptor systems due to its intrinsic frontier energy levels which typically leads to energy losses due to inadequate energy level alignment and presence of resistive losses. In this work, PEDOT:PSS:metal phthalocyanines nanocomposite thin films are formulated and used as hole transport layer for organic solar cells (OSCs). PEDOT:PSS is formulated with H2Pc, CuPc, CoPc and ZnPc metal phthalocyanines (MPc) with nanobelt morphology which confers the compatibility with the active layer. Atomic force microscopy (AFM) and x-ray diffraction (XRD) were used to study the morphology and structure of nanocomposite films, respectively. OSCs based on PEDOT:PSS:MPc nanocomposite films were fabricated and the effect of hybrid hole transport layer with various phthalocyanines on photovoltaics properties was studied. Overall, nanocomposition of PEDOT:PSS with metal phthalocyanines improves the final power conversion efficiency of solar cells by 20% by a reduction of the resistive losses due to inadequate energy level alignment. The addition of metal phthalocyanines to PEDOT:PSS is a promising method for tailor-made hole transport materials for new donor:acceptor systems to improve their efficiencies.

Indium oxide films were obtained by spin coating from a solution of indium nitrate in ethylene glycol followed by annealing at 300 °C. The influence of the thickness and surface interface of In2O3 films on the optical and photo-electrophysical properties of a polymer solar cell has been studied. It is shown that the surface roughness of the film gradually decreases with a decrease in the thickness of the film to 60 nm, and a further decrease in the thickness of the films leads to its increase. The absorption spectra of the films were measured. The values of the optical band gap width are determined. It was found that with a decrease in the thickness of the films, the width of the forbidden zone (Eg) also decreases. It was found that the parameters of the current-voltage characteristics (VAC) and electrophysical measurements also depend on the thickness and interface of the surface of the In2O3 films. It was found that with an In2O3 film thickness equal to 60 nm, a maximum efficiency value of 3.42 % is observed, at the same time, electrons in the photoactive layer have a maximum charge carrier lifetime and a low recombination rate

In the present work, phthalocyanine nanowires were obtained on the surface of glass substrates with an ITO coating. The presence of α, β, and χ crystalline phases, which are formed in the course of synthesis was demonstrated using XRD. Measurement of the absorption spectra showed that the observed change in the shape of the absorption bands is associated with the formation of phase states and the relationship between the tendency of the central metal ion to leave the phthalocyanine plane and the value of the Davydov splitting. It was found that the high-value conductivity of the nanowires is explained by the possibility of the π-electrons transition depending on the metal ion, over the states of overlapping phthalocyanine rings. An analysis of the obtained results showed that additional energy states are involved in the charge transfer mechanism, which is formed during the coordination interaction of metal ions with an organic ligand.

The paper presents the results of studies of the effect of tungsten disulfide nanoparticles on the optical and electrotransport characteristics of PEDOT: PSS thin films in polymer solar cells. Tungsten disulfide (WS2) nanoparticles were obtained by laser ablation in isopropyl alcohol. The average size of nanoparticles were determined by dynamic light scattering and is ~38 nm. The concentration of WS2 nanoparticles in the solution was calculated based on the density of the WS2 substance. The absorption spectrum of nanoparticles in isopropyl alcohol has been measured. Two bands are observed in 500-900 nm regions, which are associated with direct exciton transitions A1 and B1 in two-dimensional transition metal dichalcogenides with 2H phase. WS2 nanoparticles were added in PEDOT: PSS solution and thin films were deposited from the preparedsolution by spin-coating. PEDOT: PSS thin films doped with WS2 were studied by atomic force microscopy (AFM). The arithmetic mean deviation of the surface roughness (Ra) was estimated. Doping with WS2 nanoparticles leads to the increase in Ra of PEDOT: PSS thin films. The optical absorption spectra of doped films have been measured. Also, doping PEDOT: PSS with WS2 nanoparticles results in a long-wavelength shift of the PEDOT absorption maximum. The optimal concentration of WS2 nanoparticles for the preparation of doped PEDOT: PSS thin films is determined, at which the film resistance decreases by almost 2 times, the recombination resistance of charge carriers increases by 4.7 times, and the efficiency of the polymer solar cell increases to 1.94 %.

In this work, the effect of molybdenum disulfidenanoparticles on the properties zinc oxideelectron transport layer of organic solar cells is studied. molybdenum disulfidenanoparticles were obtained by laser ablation of MoS2 powder in isopropyl alcohol. To form composite films, nanoparticles were added to a sol–gel zinc oxidesolution with different concentrations.According to scanning electron microscope study, as the concentration of nanoparticles in the film increases, the thickness of the molybdenum disulfidelayer on the zinc oxide surface changes. molybdenum disulfidenanoparticles in the film structure gradually fill the bulk and surface voids inzinc oxide. However, when the concentration exceeds 1%, holes and voids are formed in the film. The absorption spectra of composite films showed that as the concentration of nanoparticles in the film increases, the absorption intensity enhances due to theincrease of the overall thickness. At the same time, zinc oxideoptical band gap width doesnot change, which means the molybdenum disulfidenanoparticles do not affect the electronic structure of zinc oxide. It was shown that the observed changes in the volt-ampere characteristicof organic solar cells with composite films electron transport layer composite films was associated with the influence of molybdenum disulfidenanoparticles on electron transport in organic solar cells.According to impedance spectroscopy study, it was found that molybdenum disulfidenanoparticles at concentration below critical value increases the lifetime of charge carriers and the diffusion coefficient in composite film.

Dense TiO2 thin films are widely used as electron transport layers in perovskite solar cells. TiO2 is a high band gap semiconductor with n-type conductivity showing excellent compatibility with metal-halide perovskites in terms of energy alignment providing efficient charge separation and less energy loss of electrons during electron transfer. In this work, TiO2 layers were deposited from TiO2 sol-gel solution by spin-coating methods. The optimization of TiO2 ETL thickness is a necessary procedure to reduce ETL resistance and minimize charge recombination. The thickness reduction leads to a decrease in resistance, however, also enhances charge recombination due to the formation of pin-holes and cracks. We found that TiO2 thickness reduction also causes the TiO2 defects density changes. By studying luminescence spectra of TiO2 with various thicknesses we found that the thickness reduction leads to the increase in the interstitial Ti+3 defects density, while the oxygen va-cancies density decreases. Ti+3 species form deep levels trapping free electrons and as result increasing TiO2 resistance. TiO2 films with thicknesses in the range of 40-120 nm were deposited and used as ETL for PSCs with ITO/TiO2/CH3NH3I3PbClx/CuPc/MoOx/Ag structure. Our study revealed two competitive charge transport processes taking place in TiO2: electron transport through the TiO2 conduction band and electron trapping by deep trap levels formed by Ti+3 species. Therefore according to the IV and IS studies, the optimal TiO2 layer thickness at which there is a balance between the competitive charge transport processes is about 60 nm for our deposition condition.

Lead halide perovskite CH3NH3PbClxI3-x thin films are widely used as photoactive layers in perovskite solar cells. CH3NH3PbClxI3-x is a low band gap semiconductor with a broad absorption spectrum and a high conductivity showing excellent compatibility with exciting hole and electron selective layers in terms of electronic energy alignment, which provide efficient charge generation, separation and transport in perovskite solar cells. In this paper, CH3NH3PbClxI3-x layers were deposited on the TiO2 surface by one step spin-coating technique from a methylammonium iodide (MAI) and lead chloride (PbCl2) solution. To prepare the perovskite solution, PbCl2 (Sigma-Aldrich) 230 mg of PbCl2 and 394 mg of MAI were dissolved in 1 ml of N, N-Dimethylformamide (Sigma-Aldrich) solvent. As expected, the elevation of the spin-coating rate resulted in CH3NH3PbClxI3-x thickness reduction, which should lead to a decrease in the R3 resistance in CH3NH3PbClxI3-x. However, the impedance spectroscopy revealed that with thickness reduction from 955 nm to 753 nm, the R3 resistance of CH3NH3PbClxI3-x declines from about 2590 Ώ to 2258 Ώ reaching the minimum value at 505 nm. The further decrease in CH3NH3PbClxI3-x thickness increased CH3NH3PbClxI3-x film resistance. The study of CH3NH3PbClxI3-x absorbance and luminescence spectra showed that the change in CH3NH3PbClxI3-x defect density occurred, which explains the decrease in CH3NH3PbClxI3-x resistance. According to the absorbance and luminescence spectroscopy study, the CH3NH3PbClxI3-x thickness reduction led to a decrease in the density of interstitial CH3NH3PbClxI3-x+ defects. CH3NH3PbClxI3-x+ species form deep levels trapping free electrons and as a result, increasing CH3NH3PbClxI3-x resistance. The PSCs based on a 505 nm thick CH3NH3PbClxI3-x layer showed the highest performance with the improved short current density and fill factor. The champion device had a power conversion efficiency of 9.92 %.

In this study, SnOx films were synthesized via thermal oxidation of Sn films at various temperatures ranging from 300 degrees C to 500 degrees C. The impact of oxidation temperature on the structural, optical, and electronic properties of the SnOx films was investigated using SEM, EDX, optical absorption, and impedance spectroscopy techniques. It was found that the oxidation temperature has a significant impact on the SnOx resistance, which decreases as the temperature increases due to improved SnOx crystallinity and enhanced electron mobility. Furthermore, an in-crease in recombination resistance suggests an improvement in interface quality and reduced charge recombi-nation processes. Finally, the impact of SnOx electron transport layer properties on the photovoltaic characteristics of organic solar cells was investigated. It was observed that OSCs based on SnOx ETL obtained at higher oxidation temperature reveal enhanced photovoltaic characteristics.