Enhancement of thermoelectric performance of PEDOT:PSS films by post-treatment with a superacid

Several methods such as the addition of a polar solvent, an acid as well as various post-treatments have been used to improve the thermoelectric performance of conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) films. This paper reports a method using a superacid, trifluoromethanesulfonic acid, in methanol to treat PEDO:PSS films to improve their thermoelectric performance. Treatment of PEDOT:PSS films with this superacid in methanol leads to a significant increase in electrical conductivity from 0.7 to 2980 S cm⁻¹ together with a moderate increase in Seebeck coefficient from 17.6 to 21.9 μV K⁻¹, giving a power factor of 142 μW m⁻¹ K⁻², one of the highest values reported in the literature for conductive polymers. The figure of merit (ZT) value is estimated to be 0.19 under optimized conditions. The enhancement of thermoelectric performance, particularly the increase in both electrical conductivity and Seebeck coefficient, is due to the removal of the insulating component and polymer chain realignment giving in turn a denser packing of the conductive PEDOT polymer chains. This post-treatment method would offer an alternative way to improve the thermoelectric performance.

Treatment of PEDOT:PSS films with a superacid results in remarkable improvement of thermoelectric performance with a power factor of 142 μW m⁻¹ K⁻².     

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.     

Facile synthesis of highly conductive PEDOT:PSS via surfactant templates

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanoparticles in powder form with high electrical conductivity were synthesized via chemical oxidative polymerization. In addition, the effects of EDOT : PSS weight ratio, EDOT : Na₂S₂O₈ mole ratio, and surfactant concentration and type, namely hexadecyltrimethylammonium bromide (CTAB), sodium dodecylsulfate (SDS), and polyoxyethylene octyl phenyl ether (Triton X-100) on the properties of PEDOT:PSS were investigated. For the effect of EDOT : PSS weight ratio, at the EDOT : Na₂S₂O₈ mole ratio of 1 : 1, the EDOT : PSS weight ratio of 1 : 11 was the optimal condition to obtain electrical conductivity of 999.74 ± 10.86 S cm⁻¹ due to the high amount of PSS⁻ and SO₄²⁻ available to interact with the PEDOT chain with a low % PSSNa. For the effect of EDOT : Na₂S₂O₈ mole ratio, at the EDOT : PSS weight ratio of 1 : 11, the EDOT : Na₂S₂O₈ mole ratio of 1 : 2 was the best condition as it provided the highest dopant (PSS⁻ and SO₄²⁻) amount, while the % PSSNa was relatively low. For the effect of surfactant type and concentration, at the EDOT : PSS weight ratio of 1 : 11 and EDOT : Na₂S₂O₈ mole ratio of 1 : 2, Triton X-100 at 2.5CMC provided electrical conductivity higher than with CTAB and SDS. The thermal stability of PEDOT:PSS obtained from various conditions was investigated, and PEDOT:PSS without surfactant showed the highest thermal stability since it produced the highest char yield. In this study, the highest electrical conductivity of PEDOT:PSS, which was obtained in the presence of Triton X-100 to reduce the PSSNa amount, was 1879.49 ± 13.87 S cm⁻¹, the highest value reported to date.

The electrical conductivity of 1879.49 ± 13.87 S cm⁻¹ was achieved for PEDOT:PSS, which is the highest value reported to date.     

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.     

Effect of molecular weight distribution of PSSA on electrical conductivity of PEDOT:PSS

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most successful conductive polymer. In this study, we investigated the electrical properties of PEDOT:PSS prepared using poly(styrenesulfonic acid) (PSSA) having different molecular weight distributions. Herein PSSA with different molecular weight distributions were successfully polymerized by free radical polymerization and atom-transfer radical polymerization (ATRP). Polydispersity index values of PSSA obtained by the free radical process and ATRP process were 2.3–2.8 and 1.2–1.6 respectively. The electrical conductivity of PEDOT:PSS was enhanced from 376 S cm⁻¹ (prepared using free radical PSSA) to 422 S cm⁻¹ (prepared using ATRP PSSA) when PSSA of Mn 35 000 g mol⁻¹ PSSA was used and was enhanced from 234 S cm⁻¹ (prepared using free radical PSSA) to 325 S cm⁻¹ (prepared using ATRP PSSA) when PSSA of Mn 55 000 g mol⁻¹ was used, by a factor of 15–30%. The greater the regularity of PSSA, the greater the packing density of PEDOT:PSS and consequently, charge carrier density. The improvement of packing density of PEDOT:PSS was confirmed by improvement in crystallinity of PEDOT:PSS by X-ray diffraction (XRD) analysis.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most successful conductive polymer.     

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.     

Improving the performance of proton exchange membrane water electrolyzers with low Ir-loaded anodes by adding PEDOT:PSS as electrically conductive binder

Reducing the iridium catalyst loading in the anode of polymer electrolyte membrane electrolyzers is a major goal to bring down the cost. However, anodes with low Ir-loading can suffer from poor electrical connectivity and hence lower the efficiency of the electrolyzer. In this work, we replace parts of the Nafion binder in the anode with an electrically conductive polymer (poly-3,4-ethylenedioxythiophene and polystyrene sulfonate acid complex, PEDOT:PSS) to counter this effect. At the optimal 50 : 50 blend we achieve a 120 mV lower overpotential (2.02 V) at 3 A cm⁻² compared to a pure Nafion reference (2.14 V). This corresponds to a 6% better efficiency. Ex situ resistivity measurements and high frequency resistance measurements indicate that the major cause for this improvement lies in the reduced electrical in-plane resistance due to the electrical conductivity of PEDOT:PSS.

Partial substitution of the Nafion binder with PEDOT:PSS resulted in higher efficiency of proton exchange membrane water electrolyzers thanks to the improved in-plane electrical conductivity in the electrode.     

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.     

Detection of xanthine in food samples with an electrochemical biosensor based on PEDOT:PSS and functionalized gold nanoparticles

An innovative biosensor assembly relying on glassy carbon electrodes modified with nanocomposites consisting of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a host matrix with functionalized gold nanoparticles (GCE/PEDOT:PSS-AuNPs) is presented for the selective and sensitive detection of xanthine (XA). The developed sensor was successfully applied for the quantification of XA in the presence of significant interferents like hypoxanthine (HXA) and uric acid (UA). Different spectroscopy and electron microscopy analyses were done to characterize the as-prepared nanocomposite. Calibration responses for the quantification of XA was linear from 5.0 × 10⁻⁸ to 1.0 × 10⁻⁵ M (R² = 0.994), with a detection limit as low as 3.0 × 10⁻⁸ (S/N = 3). Finally, the proposed sensor was applied for the analyses of XA content in commercial fish and meat samples and satisfactory recovery percentage was obtained.

An innovative biosensor with glassy carbon electrodes modified with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate nanocomposites as a host matrix with functionalized gold nanoparticles for the selective and sensitive detection of xanthine.     

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.     

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.     

Electrocatalytic reduction of oxygen at platinum nanoparticles dispersed on electrochemically reduced graphene oxide/PEDOT:PSS composites

Composites of commercially available graphene oxide (GO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with solvent additive ethylene glycol (EG) were investigated as an alternative support for Pt nanoparticles towards the electrocatalytic reduction of oxygen. The surface characteristics of the materials were examined using atomic force microscopy (AFM), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS). Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) at rotating disk electrodes (RDEs) and rotating ring-disk electrodes (RRDEs) were used to characterise the electrocatalytic activities of the composites materials. The structural and electrochemical studies reveal that the addition of EG favours the homogeneous distribution of Pt particles with reduced particle size and improves the electrocatalytic properties. A 30% and 16% increase in electrochemically active surface area (ECSA), a 1.2 and 1.1 fold increase in specific area activity (SA), and a 1.5 and 1.2 fold increase in mass activity (MA) were observed for 30% and 40% Pt loading on PEDOT:PSS after the addition of EG. A composite of rGO and PEDOT:PSS(EG) was investigated for different (w/w) ratios of PEDOT:PSS and rGO. The 1 : 2 w/w ratio showed an enhanced catalytic activity with high limiting current, more positive onset potential, higher SA and MA with lower H₂O₂ yield compared to PEDOT:PSS(EG) and rGO and previously reported values for PEDOT:PSS.

Composites of commercially available graphene oxide and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) with solvent additive ethylene glycol were investigated as an alternative support for Pt nanoparticles towards the electrocatalytic reduction of oxygen.     

Highly stretchable transparent bar coated Ag NW/PEDOT:PSS hybrid electrode for wearable and stretchable devices

In this study, we demonstrated poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) as a composite with Ag nanowire (Ag NW) to enhance the stretchability of the Ag NW network electrode. The composite Ag NW/PEDOT:PSS hybrid ink (AP ink) was prepared at a ratio of 1 : 10, 1 : 20, and 1 : 30, respectively and bar coated on polyurethane substrate. The different ink ratios were studied and optimized with a sheet resistance of 14.93 Ω sq⁻¹. and a transmittance of 88.6% showing a high performance in mechanical stress tests such as bending, folding, rolling, twisting, and stretching. It also showed a conductive bridge effect where the PEDOT:PSS acted as an anchor or support to Ag NW during mechanical strain and PEDOT:PSS also enhanced the electrical conductivity of the Ag NW. Therefore, to prove the real time performance of the electrode as a wearable device, we fabricated transparent electroluminescence devices and thin film heater devices which are highly flexible and demonstrated excellent performance proving that the AP electrode is more suitable candidate for future wearable transparent devices.

PEDOT:PSS, the highly stretchable and conductive polymer, can enhances the stretchability of Ag NW electrodes when mixed with Ag NW. Because PEDOT:PSS is still connected to the disconnected Ag NWs, the electrode has enhanced stretchability.     

Improving the efficiency of n-Si/PEDOT:PSS hybrid solar cells by incorporating AuNP-decorated graphene oxide as a nanoadditive for conductive polymers

A gold nanoparticle-decorated graphene oxide (GO-AuNP) hybrid material was prepared by using the chemical reduction method. The obtained results showed that the AuNPs of about of 15 nm are well bound on the surface of GO. The GO-AuNP hybrid material was used for transparent conductive film (TCF) and organic/inorganic hybrid solar cells. The TCF based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) containing GO-AuNPs was fabricated at room temperature. The obtained results show that the TCF containing 0.5 wt% GO-AuNPs has a high transmittance of 69.7% at 550 nm, a low sheet resistance of 50.5 Ω □⁻¹ and a conductivity that increased to 3960 S cm⁻¹, which is three times higher than those of the PEDOT:PSS and PEDOT:PSS/GO film. The power conversion efficiency (PCE) of the n-Si/PEDOT:PSS hybrid solar cell containing GO-AuNPs was 8.39% and is higher than pristine PEDOT:PSS (5.81%) and PEDOT:PSS/GO (7.58%). This is a result of the increased electrical conductivity and localized surface plasmon resonance of the PEDOT:PSS coating layer containing the GO-AuNP hybrid material.

A GO-AuNP hybrid material was successfully prepared and used for improving the performance of the optoelectronics devices.     

Consequences of gamma-ray irradiation on structural and electronic properties of PEDOT:PSS polymer in air and vacuum environments

In this work, the effects of gamma-ray irradiation (up to 3 kGy) on the structural and electronic properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), irradiated in air and vacuum environments are systematically investigated. Raman spectroscopy indicates that there is no significant change in structural conformation of PEDOT:PSS film after gamma-ray irradiation. However, the conductivity of the film decreases as a function of dose in both air and vacuum environments, which can be deduced as a result of defects created in the structure. Hall effect measurements showed higher carrier concentration when the samples are irradiated under vacuum in comparison to the air environment, whereas mobility decreases as a function of dose irrespective of the environment. Furthermore, the electron spin resonance spectra provided evidence of the evolution of polaron population after gamma-ray exposure of 3 kGy, due to the decrease in charge delocalization and molecular ordering of the molecules. This decrease in conductivity and mobility of the PEDOT:PSS films irradiated in air and vacuum environments can be mainly ascribed to the defects and radical formation after gamma-ray exposure, favoring chain scission or cross-linking of the polymers.

Effects of gamma-ray irradiation (up to 3 kGy) on the structural and electronic properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), irradiated in air and vacuum environments are systematically investigated.     

Electronic performance of printed PEDOT:PSS lines correlated to the physical and chemical properties of coated inkjet papers

PEDOT:PSS organic printed electronics chemical interactions with the ink-receiving layer (IRL) of monopolar inkjet paper substrates and coating color composition were evaluated through Raman spectroscopy mapping in Z (depth) and (XY) direction, Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDS). Other evaluated properties of the IRLs were pore size distribution (PSD), surface roughness, ink de-wetting, surface energy and the impact of such characteristics on the electronics performance of the printed layers. Resin-coated inkjet papers were compared to a multilayer coated paper substrate that also contained an IRL but did not contain the plastic polyethylene (PE) resin layer. This substrate showed better electronic performance (i.e., lower sheet resistance), which we attributed to the inert coating composition, higher surface roughness and higher polarity of the surface which influenced the de-wetting of the ink. The novelty is that this substrate was rougher and with somewhat lower printing quality but with better electronic performance and the advantage of not having PE in their composite structure, which favors recycling.

PEDOT:PSS ink chemical interactions with the coated surface of inkjet papers and their composition were evaluated through Raman, FTIR and EDS. Morphology of the pores and surface energy were also evaluated and how these impact sheet resistance.     

Correction: Consequences of gamma-ray irradiation on structural and electronic properties of PEDOT:PSS polymer in air and vacuum environments

Correction for ‘Consequences of gamma-ray irradiation on structural and electronic properties of PEDOT:PSS polymer in air and vacuum environments’ by Aswin kumar Anbalagan et al., RSC Adv., 2021, 11, 20752–20759, DOI: 10.1039/D1RA03463D.

The authors regret that incorrect details were given for ref. 18. The correct version of ref. 18 is given here as ref. 1.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

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.     

Organic–inorganic hybrid perovskite quantum dot light-emitting diodes using a graphene electrode and modified PEDOT:PSS

Perovskite quantum dot (PQD) light-emitting diodes (LEDs) have rapidly developed in the past several years due to the excellent optoelectronic properties of lead halide perovskites. However, PQD LEDs using graphene electrodes have not been reported despite their huge potential for applications in flexible displays and lighting sources. Herein, graphene was first used as the electrode of PQD LEDs. To overcome graphene''s limitations such as hydrophobicity and graphene-induced film nonuniformity, the modification of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with Triton X-100 and dimethyl sulfoxide (DMSO) codoping was reported, which not only improved the wettability of the graphene surface and the sequent film quality, but also reduced the dissolution of the PQD solvent to the bottom poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine] and PEDOT:PSS. More importantly, the synergistic effect of Triton X-100 and DMSO altered the PEDOT:PSS morphology from a coiled structure to a nanofibril conductive network, sufficiently enhancing the electrical conductivity of PEDOT:PSS. With this modification strategy, green PQD LEDs with CH₃NH₃PbBr₃ emission layers were successfully fabricated on graphene anodes, with 3.7- and 4.4-fold enhancements in luminance and current efficiency, respectively, compared to those of their counterparts without PEDOT:PSS modification. The film modification strategy and graphene-based PQD LEDs in this work are expected to shed light on the further design and manufacture of flexible highly efficient PQD display and lighting devices.

A graphene electrode together with modified PEDOT:PSS was first applied into perovskite quantum dot light-emitting diodes to improve the device performance.     

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.