Effects of PEDOT:PSS:GO composite hole transport layer on the luminescence of perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) employing CH₃NH₃PbBr₃ as the emission layer (EML) and graphene oxide (GO) doped PEDOT:PSS as the hole transport layer (HTL) were prepared and characterized. GO doped in PEDOT:PSS can lead to the increased work function of HTL and lower the hole injection barrier at the HTL/CH₃NH₃PbBr₃ interface, which facilitates the hole injection. Meanwhile, the optimized GO amount in PEDOT:PSS can help to reduce the quenching of luminescence occurring at the interface between HTL and perovskite. The luminance and current efficiency reach the maximum values of 3302 cd m⁻² and 1.92 cd A⁻¹ in PeLED with an optimized GO ratio (0.3), which increase by 43.3% and 73.0% in comparison with the undoped device, respectively. The enhanced luminescence of PeLEDs was caused by the combined effects of enhanced hole injection efficiency and the suppressed exciton quenching occurring at the HTL/EML interface. These results indicate that the introduction of traditional two-dimensional materials is a reasonable method for designing the structure of PeLEDs.

Perovskite light-emitting diodes (PeLEDs) employing CH₃NH₃PbBr₃ as the emission layer (EML) and graphene oxide (GO) doped PEDOT:PSS as the hole transport layer (HTL) were prepared and characterized.     

Self-standing cellulose nanofiber/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/ionic liquid actuators with superior performance

This paper describes new actuators with cellulose nanofiber/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/ionic liquid (CNF/PEDOT:PSS/IL) structures. Devices containing these structures exhibit higher strain and maximum generated stress than those based on only PEDOT:PSS/IL. The new actuator system contains an electrode, which is an electrochemical capacitor, and which consists of both a faradaic capacitor (FC) and a small electric double-layer capacitor (EDLC), i.e., PEDOT:PSS. This combined capacitor plays the role of an FC and a base polymer, and the CNF skeleton is used in the place of carbon nanotubes (CNTs). This device therefore functions differently from traditional CNT/PVdF–HFP/IL actuators, which are only used as EDLC units and from PEDOT:PSS/vapor-grown carbon nanofibers (VGCF)/IL actuators, which are used as hybrid (FC and EDLC) units. The developed films are novel, robust, and flexible, and demonstrate potential as actuator materials for wearable energy-conversion devices. A double-layer charging kinetic model, which is similar to that previously proposed for PEDOT:PSS/CNT/IL actuators, is developed to explain the oxidation and reduction of PEDOT:PSS. This model successfully simulates the frequency-dependent displacement response of actuators.

This paper describes new actuators with cellulose nanofiber/PEDOT:PSS/ionic liquid (CNF/PEDOT:PSS/IL) structures. These devices show superior performance with respect to strain and maximum generated stress compared to those containing PEDOT:PSS/IL.     

Salt doping to improve thermoelectric power factor of organic nanocomposite thin films

Thermoelectric materials with a large Seebeck coefficient (S) and electrical conductivity (σ) are required to efficiently convert waste heat into electricity, but their interdependence makes simultaneously improving these variables immensely challenging. To address this problem, bilayers (BL) of poly(diallyldimethylammonium chloride) (PDDA) and double-walled carbon nanotubes (DWNT), stabilized by KBr-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were deposited using layer-by-layer (LbL) assembly. Doping PEDOT:PSS with KBr, prior to DWNT dispersion and LbL assembly, results in a six-fold improvement in electrical conductivity with little change in the Seebeck coefficient. A maximum power factor (PF = S²σ) of 626 ± 39 μW m⁻¹ K⁻² is obtained from a 20 BL PDDA/PEDOT:PSS–DWNT film (∼46 nm thick), where PEDOT:PSS was doped with 3 mmol KBr. This large PF is due to the formation of a denser film containing a greater proportion of DWNT, which was influenced by the charge-screening effects imparted by the salt dopant that separates PSS from PEDOT. This study demonstrates a relatively simple strategy to significantly increase the thermoelectric performance of fully organic nanocomposites that are useful for low temperature thermoelectric devices.

Thermoelectric power factor of a polymer nanocomposite film, deposited using layer-by-layer assembly, was increased by doping with KBr.     

Enhanced power conversion efficiency of an n-Si/PEDOT:PSS hybrid solar cell using nanostructured silicon and gold nanoparticles

Herein, the effect of nanostructured silicon and gold nanoparticles (AuNPs) on the power conversion efficiency (PCE) of an n-type silicon/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (n-Si/PEDOT:PSS) hybrid solar cell was investigated. The Si surface modified with different nanostructures including Si nanopyramids (SiNPs), Si nanoholes (SiNHs) and Si nanowires (SiNWs) was utilized to improve light trapping and photo-carrier collection. The highest power conversion efficiency (PCE) of 8.15% was obtained with the hybrid solar cell employing SiNWs, which is about 8%, 20% and 40% higher compared to the devices using SiNHs, SiNPs and planar Si, respectively. The enhancement is attributed to the low reflectance of the SiNW structures and large PEDOT:PSS/Si interfacial area. In addition, the influence of AuNPs on the hybrid solar cell''s performance was examined. The PCE of the SiNW/PEDOT:PSS hybrid solar cell with 0.5 wt% AuNP is 8.89%, which is ca. 9% higher than that of the device without AuNPs (8.15%). This is attributed to the increase in the electrical conductivity and localized surface plasmon resonance of the AuNP-incorporated PEDOT:PSS coating layer.

n-Si/PEDOT:PSS hybrid solar cells using nanostructured silicon and AuNPs were prepared and investigated.     

Improving the performance of quantum-dot light-emitting diodes via an organic–inorganic hybrid hole injection layer

Poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) is a commonly used material for the hole injection layer (HIL) in quantum-dot light-emitting diodes (QLEDs). In this work, we improved the performance of the QLED by using an organic–inorganic hybrid HIL. The hybrid HIL was prepared by mixing PEDOT:PSS with vanadium oxide (V₂O₅), which is a transition-metal oxide (TMO). The hole injection properties of PEDOT:PSS were improved according to the amount of V₂O₅ mixed into the PEDOT:PSS. The maximum luminance and current efficiency were 36 198 cd m⁻² and 13.9 cd A⁻¹, respectively, when the ratio of PEDOT:PSS and V₂O₅ was 10 : 1. Moreover, the operating lifetime exceeded 300 h, which is 10 times longer than the lifetime of the device with only PEDOT:PSS HIL. The improvement was analyzed using ultraviolet and X-ray photoelectron spectroscopy. We found that the density of state (DOS) of PEDOT:PSS near the Fermi energy level was increased by mixing V₂O₅. Therefore, the increase of DOS improved the hole injection and the performance of QLEDs. The result shows that the hybrid HIL can improve the performance and the stability of QLEDs.

The performance of the quantum-dot light-emitting diodes was improved by using an organic–inorganic hybrid hole injection layer.     

Carbon electrode engineering for high efficiency all-inorganic perovskite solar cells

Carbon-based inorganic perovskite solar cells (PSCs) have demonstrated an excellent performance in the field of photovoltaics owing to their simple fabrication techniques, low-cost and superior stability. Despite the lower efficiency of devices with a carbon electrode compared with the conventional structure, the potential applications in large scale have attracted increasing attention. Herein, we employ a mixed carbon electrode inorganic PSC by incorporating one-dimensional structure carbon nanotubes (CNTs) and two-dimensional Ti₃C₂-MXene nanosheets into a commercial carbon paste. This mixed carbon electrode, which is different from the pure carbon electrode in showing a point-to-point contact, provides a network structure and multi-dimensional charge transfer path, which effectively increases the conductivity of the carbon electrode and carriers transport. A respectable power conversion efficiency of 7.09% is obtained through carbon/CNT/MXene mixed electrode in CsPbBr₃-based solar cells.

A carbon/CNT/MXene mixed electrode in CsPbBr₃ solar cells provides a network structure and multi-dimensional charge transfer path, which effectively increases the conductivity of the carbon electrode and carriers transport.     

Work function modification of PEDOT:PSS by mixing with barium acetylacetonate

Poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS) is often used as a hole injection and extractor for various organic electronic devices. This study investigated whether it is possible to n-dope PEDOT:PSS with barium acetylacetonate (Ba(acac)₂) to change its work function so that to be more suitable for electron injection and extraction. Molecular dynamics simulations suggested that barium cations can interact with the aromatic rings of PEDOT and the negatively charged sulfonate in PSS. At high doping concentration, we found that PEDOT became dedoped and precipitated resulting in a clear solution after filtration. The absence of the absorption peak of PEDOT at 263 nm indicates the removal of PEDOT after filtration. The shift in O 1s to a lower binding energy as seen in X-ray photoelectron spectroscopy suggested that the polystyrene sulfonic acids are being ionized to form barium polystyrene sulfonate (Ba–PSS). By spin-coating the solution on top of indium tin oxide, the work function can be adjusted to as low as 3.6 eV. The ability of such a mixture to inject and extract electrons is demonstrated using 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene as an electron transporting layer. We attributed the lowering of the work function as the result of the formation of an interfacial dipole as large as 1.37 eV at the ITO/Ba–PSS interface.

Modification of poly(3,4-ethylenedioxythiophene)polystyrene sulfonate as electron injection layer.     

A zwitterionic polymer as an interfacial layer for efficient and stable perovskite solar cells

Perovskite solar cells have been rapidly developed in the past ten years. It was demonstrated that the interfacial layer plays an important role in device performance of perovskite solar cells. In this study, we report utilization of a photoinitiation-crosslinked zwitterionic polymer, namely dextran with carboxybetaine modified by methacrylate (Dex-CB-MA), as an interfacial layer to improve the film morphology of the CH₃NH₃PbI₃ photoactive layer and the interfacial contact between the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole extraction layer and CH₃NH₃PbI₃ photoactive layer. It is found that the Dex-CB-MA thin layer forms a better band alignment between the PEDOT:PSS hole extraction layer and CH₃NH₃PbI₃ photoactive layer, and improves the crystallization of the CH₃NH₃PbI₃ photoactive layer, resulting in efficient charge carrier transport. As a result, perovskite solar cells with the PEDOT:PSS/Dex-CB-MA hole extraction layer exhibit more than 30% enhancement in efficiency and dramatically boosted stability as compared with that with the PEDOT:PSS hole extraction layer. Our studies provide an effective and facile way to fabricate stable perovskite solar cells with high power conversion efficiency.

The zwitterionic polymer, Dex-CB-MA thin layer forms a better band alignment between the PEDOT:PSS hole extraction layer and CH₃NH₃PbI₃ photoactive layer, and improve the crystallization of CH₃NH₃PbI₃ photoactive layer, resulting in efficient charge carrier transport.     

Key parameters for enhancing the thermoelectric power factor of PEDOT:PSS/PANI-CSA multilayer thin films

Among the conducting polymers, poly(3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been extensively investigated for organic thermoelectric device applications owing to its high electrical conductivity (σ), flexibility and easy processability. The thermoelectric (TE) power factor – a factor that determines the efficiency of a thermoelectric material, is very critical in developing high-efficiency thermoelectric devices. The TE power factor of PEDOT:PSS requires further enhancement in realizing efficient organic TE devices. Recently, we have reported a layer-by-layer deposition technique to deposit PEDOT:PSS and poly aniline-camphor sulfonic acid (PANI-CSA) forming a PEDOT:PSS/PANI-CSA multilayer (ML) thin film structure with an enhanced thermoelectric power factor up to 49 μW m⁻¹ K⁻¹. However, there exist several ambiguities regarding the parameters that control the TE power factor in (ML) thin films. In order to identify the parameters that control the TE power factor of ML thin films, PEDOT:PSS/PANI-CSA ML thin films have been deposited by varying the deposition conditions such as spin speed, the number of layers, solvent treatment, and thickness of each layer. A thermoelectric power factor up to 325 μW m⁻¹ K⁻¹ is achieved by properly optimizing the spin speed, number of layers, and the thickness of each layer in ML thin films. The enhanced thermoelectric power factor is the result of multiple factors such as stretching of PEDOT chains, structural conformation change from benzoid to quinoid, and excess PSS removal from the top of the PEDOT:PSS layer through solvent treatment and at the PEDOT:PSS/PANI-CSA interface. Our study provides the basis for realizing an enhanced thermoelectric power factor of organic thermoelectric multilayer structures consisting of ultra-thin polymer thin films similar to inorganic superlattices having 2D confinement.

The key factors that control the thermoelectric (TE) properties of PEDOT:PSS/PANI-CSA multilayer thin films to enhance the TE power factor.     

Reversible switching of PEDOT:PSS conductivity in the dielectric–conductive range through the redistribution of light-governing polymers

One of the biggest challenges in the field of organic electronics is the creation of flexible, stretchable, and biofavorable materials. Here the simple and repeatable method for reversible writing/erasing of arbitrary conductive pattern in conductive polymer thin film is proposed. The copolymer azo-modified poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was synthesized to achieve reversible photo-induced local electrical switching in the insulator–semimetal range. The photoisomerization of the polymer was induced by grafting nitrobenzenediazonium tosylate to the PSS main chains. While the as-deposited PEDOT:PSS thin films showed good conductivity, the modification procedure generated polymer redistribution, resulting in an island-like PEDOT distribution and the loss of conductivity. Further local illumination (430 nm) led to the azo-isomerization redistribution of the polymer chains and the creation of a conductive pattern in the insulating polymer film. The created pattern could then be erased by illumination at a second wavelength (470 nm), which was attributed to induction of reverse azo-isomerization. In this way, the reversible writing/erasing of arbitrary conductive patterns in thin polymer films was realized.

Chemical modification of PEDOT:PSS allows grafting light-switchable moieties to PSS chains and light induced reversible tuning of materials conductivity in dielectric-semimetal range.     

Influence of residual sodium ions on the structure and properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a promising conducting polymer in terms of its applicability to transparent and flexible electronic devices. Generally, a negatively charged PSS chain can interact with alkali metal cations like sodium and potassium. During polymerization, these ions, especially sodium ions, remain in an aqueous state and affect particle formation. This paper describes the effect of residual sodium ions on the synthesis of PEDOT:PSS and its electrical and optical properties. Removing the sodium ions weakens the coulombic interaction between the PEDOT and PSS chains, which leads to a linear conformation. This conformational change enhances the electrical conductivity and work function. Furthermore, transmittance in the visible region increased remarkably because the intrinsic electrical properties of the PEDOT:PSS particles were improved. Moreover, the colloidal stability was enhanced because the particle coagulation caused by residual sodium ions was reduced. In summary, we determined that sodium ions in PEDOT:PSS have a considerable influence on its electrical and optical properties and colloidal stability for practical applications.

In this study, we investigated the effects of metal ions, namely sodium ions, on the structure of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) during polymerization and the resulting electrical and optical properties.     

Improvement of PEDOT:PSS linearity via controlled addition process

Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), which is a conductive polymer, has gained immense attention as a next-generation transparent electrode. However, in order to realize its practical application, it is imperative that its optical and electrical properties should be improved. Generally, acid dopants are added to improve optical and electrical properties. In this study, however, we replaced the batch process used for manufacturing PEDOT:PSS with a controlled addition process to improve its optical and electrical properties efficiently without additional additives and processes. In this process, the rate of polymerization and the structure of the product could be regulated by controlling the amount of monomer and catalyst. Moreover, we investigated the efficiency of the controlled addition process both theoretically and experimentally. The proposed approach was used to increase the linearity of PEDOT and the proportion of PEDOT attached to the PSS chain to improve transmittance by 6.2% (73 to 79.2% at 100 ohm) and conductivity by 39.68% (446 to 623 S cm⁻¹). It was determined that the properties of PEDOT:PSS could be improved using the proposed method during the polymerization process.

PEDOT:PSS linearity enhancement using controlled addition process.     

Investigation of electronic properties of chemical vapor deposition grown single layer graphene via doping of thin transparent conductive films

It is a crucial challenge to obtain the desired electronic properties of two-dimensional materials for various ubiquitous applications and improvements in the existing technology. In this article, we have demonstrated the modulation in electronic features of the chemical vapor deposition (CVD) grown single-layer graphene (SLG) via wet doping of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The PEDOT:PSS is well known as conducting polymer and used as transparent conducting electrode in flexible organic electronic devices. The effect of doping on SLG samples were examined by Raman spectroscopy, electrical transport measurement, atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). The Raman peaks position of doped samples provided sought evidence of p-type doping of SLG after the deposition of PEDOT:PSS films. The electrical measurement confirmed the p-type doping of SLG and also revealed enhanced carrier density and mobility of SLG after the deposition of PEDOT:PSS films. AFM micrographs revealed the homogeneous loading of PEDOT:PSS particles over the SLGs. Further, KPFM technique was used to estimate the work function modulation of SLG after PEDOT:PSS film deposition. Our investigation will be useful for understanding the device physics as well as improvement of photovoltaic devices based on PEDOT:PSS coated graphene.

The tuning of charge carrier of graphene is a potential step for the realization of multifunctional use in current electronic/optoelectronic devices.     

Modulation of the doping level of PEDOT:PSS film by treatment with hydrazine to improve the Seebeck coefficient

As the most popular conducting polymer, poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely used for a variety of applications, including thermoelectrics. This paper reports the modulation of the doping level by treatment with hydrazine to improve the Seebeck coefficient of PEDOT:PSS films. PEDOT:PSS films were first treated with formic acid followed by hydrazine, leading to a significant increase in the Seebeck coefficient from 17.5 to 42.7 μV K⁻¹, about 2.5 times higher than that of the pristine film partially at the expense of electrical conductivity. An optimum power factor of 93.5 μW K⁻² m⁻¹, being 2.4 times that of the one treated with only formic acid, was achieved. The substantial improvement in the Seebeck coefficient and the power factor is collectively attributed to the removal of the PSS, and more importantly, the reduction of the doping level of PEDOT by the hydrazine treatment, which is evidenced clearly by UV-vis-NIR spectroscopy, XPS and Raman spectroscopy.

This paper reported the modulation of the doping level of PEDOT:PSS with hydrazine to remarkably improve its Seebeck coefficient.     

Simultaneous improvement in electrical conductivity and Seebeck coefficient of PEDOT:PSS by N2 pressure-induced nitric acid treatment

As a thermoelectric (TE) material suited to applications for recycling waste-heat into electricity through the Seebeck effect, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS) is of great interest. Our research demonstrates a comprehensive study of different post-treatment methods with nitric acid (HNO₃) to enhance the thermoelectric properties of PEDOT:PSS. The optimum conditions are obtained when PEDOT:PSS is treated with HNO₃ for 10 min at room temperature followed by passing nitrogen gas (N₂) with a pressure of 0.2 MPa. Upon this treatment, PEDOT:PSS changes from semiconductor-like behaviour to metal-like behaviour, with a simultaneous enhancement in the electrical conductivity and Seebeck coefficient at elevated temperature, resulting in an increase in the thermoelectric power factor from 0.0818 to 94.3 μW m⁻¹ K⁻² at 150 °C. The improvement in the TE properties is ascribed to the combined effects of phase segregation and conformational change of the PEDOT due to the weakened coulombic attraction between PEDOT and PSS chains by nitric acid as well as the pressure of the N₂ gas as a mechanical means.

As a thermoelectric (TE) material suited to applications for recycling waste-heat into electricity through the Seebeck effect, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS) is of great interest.     

Roll-to-roll continuous carbon nanotube sheets with high electrical conductivity

Large scale manufacturing of electrically conductive carbon nanotube (CNT) sheets with production capability, low cost, and long-term electrical performance stability is still a challenge. A new method to fabricate highly conductive continuous buckypaper (CBP) with roll-to-roll production capability and relatively low cost is reported. The electrical conductivity of CBP can be improved to 7.6 × 10⁴ S m⁻¹ by using an oxidant chemical (i.e. HNO₃ and I₂) doping method. To compensate for the conductivity degradation caused by the instability of the oxidant chemical doping, a polymer layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was coated on the chemically doped CBP. The fabricated highly conductive CBP showed stable electrical performance in air for more than a month. This CBP material with high electrical conductivity, relatively low cost, and roll-to-roll manufacturing capability could enable a wide range of engineering applications including flexible conductors, electromagnetic interference (EMI) shielding materials, and electrodes in energy devices.

Highly electrically conductive, roll-to-roll continuous buckypaper (CBP) with stable performance was achieved by chemical doping and polymer coating (PEDOT:PSS).     

A novel 3-methylthiophene additive to boost the performance and stability of perovskite solar cells

Perovskite solar cells (PSCs) have emerged as a practical candidate for new-generation photovoltaic devices to meet global energy demands. Recently, researchers'' attempts have been focused on the crucial issues related to PSCs, i.e., stability and performance. In this research, MAPbI₃-based PSCs were prepared via a two-step deposition process. To boost the power conversion efficiency (PCE) of the prepared PSCs, an additive engineering approach was employed. A novel 3-methylthiophene (MTP) organic molecule was added to the methylammonium iodide (MAI)/isopropanol (IPA) solution precursor. The additive improved the crystallinity of the perovskite layer, which indicates a more desirable film with lower surface defects and larger particle size. Modified PSCs reduced carries recombination rate at the interfacial of perovskite/hole transport layer (HTL), and the charge transport process is facilitated due to a desirable delocalized π-electron system of the MTP additive. The PCE of PSCs in the presence of MTP additive improved from 12.32% to 16.93% for pristine devices. Importantly, MTP-based PSCs showed higher ambient air stability due to the hydrophobic structure of MTP compared to pristine PSCs.

Perovskite solar cells (PSCs) have emerged as a practical candidate for new-generation photovoltaic devices to meet global energy demands.     

Strong electron acceptor additive based spiro-OMeTAD for high-performance and hysteresis-less planar perovskite solar cells

As the most popular hole-transporting material (HTM), spiro-OMeTAD has been extensively applied in perovskite solar cells (PSCs). Unluckily, the pristine spiro-OMeTAD film has inferior conductivity and hole mobility, thus limiting its potential for application in high-performance PSCs. To ameliorate the electrical characteristics of spiro-OMeTAD, we employ 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a strong electron acceptor into spiro-OMeTAD in PSCs. The incorporation of DDQ with spiro-OMeTAD not only improves the conductivity and the Fermi energy level, but also reduces the trap states and nonradiative recombination, which accounts for the remarkable enhancement in both the fill factor (FF) and open-circuit voltage (V_OC) of PSCs. Consequently, the champion PSC with DDQ doped hole transport layer (HTL) generates a boosted power conversion efficiency (PCE) of 21.16% with an FF of 0.796 and a V_OC of 1.16 V. Remarkably, DDQ modified devices exhibit superb device stability, as well as mitigated hysteresis. This study provides a facile and viable strategy for dopant engineering of HTL to realize highly efficient PSCs.

A perovskite solar cell with DDQ doped spiro-OMeTAD HTL delivers a champion power conversion efficiency of 21.16%.     

Visible photodetector based on transition metal-doped ZnO NRs/PEDOT:PSS hybrid materials

A hybrid Cu-doped ZnO nanorods (ZnO:Cu NRs)/poly(3,4 ethylene dioxythiophene)-polystyrene sulfonate (PEDOT:PSS)-based photodetector was fabricated using a simple hydrothermal method with pre-patterned silver electrodes. In the hybrid structure, PEDOT:PSS with high mobility acts as a carrier transport layer, while ZnO:Cu NRs with high visible absorption works as an “antenna” material to generate electron–hole pairs under light illumination. As a result, the devices exhibits a high response in visible light at a wavelength of 395 nm. The responsivity and photoconductive gain of the hybrid photodetector reached 0.33 A W⁻¹ and 1.306, respectively, which is 1.36 times higher than those of Cu-doped ZnO NRs-based ones. The response and recovery times are improved, with values of 25.21 s and 42.01 s, respectively. The development of hybrid materials for visible photodetectors enables an innovative approach for future optoelectronic devices, especially optical sensors.

This study reports the fabrication of a hybrid photodetector based on Cu-doped ZnO NRs/PEDOT:PSS, which improves the device''s performance and applications.     

Highly stretchable polymer-dispersed liquid crystal-based smart windows with transparent and stretchable hybrid electrodes

We report on highly stretchable polymer dispersed liquid crystal (PDLC)-based smart windows using Ag nanowires (NWs) and conductive PEDOT:PSS hybrid electrodes. By bar coating a Ag NW and PEDOT:PSS mixed ink on a transparent and stretchable polyurethane (PU) substrate, we fabricated highly transparent and stretchable hybrid electrodes with a sheet resistance of 40 ohm per square, an optical transmittance of 82%, and a stretchability of 30% to replace conventional brittle ITO electrode. Bending and stretching tests demonstrated that the mechanical properties of the Ag NW and PEDOT:PSS hybrid electrode were better than those of the ITO/PU sample. The Ag NW/PEDOT:PSS hybrid film was employed as a transparent and stretchable electrode (TSE) in PDLC-based stretchable smart windows, an application that is impossible for brittle ITO-based smart windows. The stretchable PDLC-based smart windows exhibited an on-state transmittance of 56% at an applied voltage of 80 V and an off-state transmittance of 2% at 0 voltage. Unlike an ITO-based PDLC smart window, which is easily broken by stretching, the Ag NW/PEDOT:PSS hybrid electrode-based PDLC smart window was stretched up to 30%. Successful operation of the stretchable PDLC-based smart window indicates that Ag NW/PEDOT:PSS hybrid films are promising TSEs for cost-effective, large area, and stretchable smart windows.

Stretchable PDLC window fabricated on the stretchable Ag nanowire and PEDOT:PSS hybrid electrodes.