Cu2S Counter Electrode Research Articles

Controlled growth of Cu3Se2 nanosheets array counter electrode for quantum dots sensitized solar cell through ion exchange

Copper selenide (Cu x Se) has great potential as counter electrode for quantum dots sensitized solar cell (QDSSC) due to its excellent electrocatalytic activity and lower charge transfer resistance. A novel ion exchange method has been utilized to fabricate Cu3Se2 nanosheets array counter electrode. CdS layer was first deposited by sputtering and used as a template to grow compact and uniform Cu3Se2 film in a typical chemical bath. The morphology and thickness of the Cu3Se2 nanosheets were controlled by the deposition time. The final products (2h-Cu3Se2) showed significantly improved electrochemical catalytic activity and carrier transport property, leading to a much increased power conversion efficiency (4.01%) when compared with the CuS counter electrode CdS/CdSe QDSSC (3.21%).

Improving the efficiency of quantum-dot-sensitized solar cells by optimizing the growth time of the CuS counter electrode

CuS counter electrodes (CEs) were prepared to fabricate efficient quantum-dot-sensitized solar cells (QDSSCs) based on a CdS/CdSe photo sensitizer. The CEs were prepared on a fluorine-doped tin oxide (FTO) glass substrate by a facile chemical bath deposition (CBD) method by dissolving CuSO4·5H2O and CH3CSNH2 in water, followed by adding 0.25mM polyvinylpyrrolidone (PVP). The CBD was performed at 60°C for 1h, 2h, and 3h, and the samples were labeled as CuS 1h, CuS 2h, and CuS 3h, respectively. The QDSSCs were assembled using prepared CuS CEs and a TiO2/CdS/CdSe/ZnS photoanode, and the effect of the growth time of CuS CEs on the QDSSC performance was investigated. As the CuS growth time increases, the short-circuit current density (Jsc), fill factor (FF), and open-circuit voltage (Voc) of the QDSSCs gradually increases, leading to an enhanced power conversion efficiency (η). QDSSCs that use the CuS 2h CE exhibit a high Jsc of 14.31mAcm−2, Voc of 0.603V, and FF of 0.49, which are higher than that using conventional Pt electrodes as well as CuS 1h and CuS 3h electrodes. The electrochemical impedance spectroscopy results show that the CuS 2h CE exhibits an inferior charge transfer resistance of only 2.93Ω, which is 33 times lesser than that of the Pt CE. The enhanced device performance of CuS 2h is ascribed to the high catalytic activity and low charge transfer resistance of the CuS CE in the reduction process of oxidized polysulfide. Consequently, a superior power conversion efficiency of 4.27% is achieved for QDSSCs utilizing CuS 2h.

Fabrication of solar cells made with CuInTe2−xSex quantum dots sensitized hierarchical TiO2 sphere having a CuS counter electrode: Dependence on the Te/Se ratio

In this study, we have succeeded in fabricating quantum dot sensitized solar cells (QDSSC’s) which utilize the semiconductor CuInTe2−xSex (of different Te/Se ratios) quantum dots sensitized hierarchical TiO2 sphere (HTS) having CuS as the photoanode. The solar to electric energy conversion performance of the resulting QDSSC depends strongly on the Te/Se ratios in the ternary chalcopyrite compound. In this study, the assembled device exhibiting the highest energy conversion efficiency η of 3.751% (Voc=0.683V, Jsc=11.707mAcm−2, FF=0.516) is the one having CuInTe1.2Se0.8 quantum dots. This value is quite an improvement over those of the CuInTe2 (η=1.970%) and CuInSe2 (η=2.286%). The efficiency of the devices decreases as the Se increases.

Optimization of performance and stability of quantum dot sensitized solar cells by manipulating the electrical properties of different metal sulfide counter electrodes

Fabrication of low cost and high catalytic active counter electrode (CE) for quantum dot sensitized solar cells is one of the dynamic ways to enhance the performance of quantum dot solar cell. In this investigation, different CE materials such as copper sulfide (Cu2S), cobalt sulfide (CoS) and nickel sulfide (NiS) were deposited on fluorine doped tinoxide (FTO) glass and brass plate by single step electrophoretic deposition technique and solar cell performance and stability of three different CEs were tested. Electrochemical deposition parameters were optimized for the optimization of CEs performance. Electrical properties of Cu2S, CoS and NiS CEs were investigated by electrochemical impedance spectroscopy and electrical properties were compared with the observed solar cell performances and stability. Of the tested CEs materials, enhanced solar cell performance was observed with Cu2S CE than the CoS or NiS CEs while brass substrae was found to be a better substrate than FTO for these CE materials. The optimized Cu2S/brass plate CE showed current density of (Jsc) 17.9mA.cm−2, open circuit voltage of (Voc) 494.5mV, fill factor of (FF) 59.0% and efficiency of 5.2% with the solar cell fabricated with PbS/CdS q-dot anode. While Cu2S/FTO glass plate CE showed Jsc of 16.1mA.cm−2, Voc of 489.4mV, FF of 52.9% and efficiency of 4.2% of with the same q-dot anode. A higher electrocatalytic activity together with the lower charge transfer resistance (Rct) and good inter-connected Cu2S particles on brass electrodes were found to be the major CE properties that decides the performance of CE.

Improving the stability of CdS quantum dot sensitized solar cell using highly efficient and porous CuS counter electrode

Thin films from copper sulfide (CuxS) are the most commonly used electrocatalyst counter electrodes (CEs) for high-efficiency quantum dot sensitized solar cells (QDSSCs) because of its superior electrocatalytic activity in the presence of polysulfide electrolytes. In addition to the stability issues, the CuxS CEs are usually prepared by complicated, costly, time consuming, and less productive methods, which are inadequate for practical applications of QDSSCs. In this work, we present a simple approach for fabricating an efficient and stable CE for QDSSCs using pure covellite phase CuS nanoparticles (NPs) pre-prepared via a cheap, fast, and scalable chemical method. The catalyst ink was obtained by mixing the as-prepared CuS NPs with polyvinylidene fluoride, as a polymeric binder, which was then directly applied to a conductive fluorine-doped tin oxide substrate without any further high temperature post treatment. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements were used to investigate the electrocatalytic activity of the CuS NPs CE. The power conversion efficiency of 2.6% was achieved from CdS QDSSC assembled with CuS NPs CE, which was higher than 1.57% for conventional Cu2S/brass and 1.33% for Pt CEs under one-sun illumination. The CdS QDSSC with CuS NPs CE was also able to supply a constant photocurrent value without any obvious decrease under light soaking test, in contrast to the devices with Cu2S/brass and Pt CEs, which showed inferior stability. This remarkable photovoltaic performance was attributed to the nanoporous morphology and the excellent electrocatalytic activity of CuS NPs CE.

Enhanced photovoltaic performance of quantum dot-sensitized solar cells with a progressive reduction of recombination using Cu-doped CdS quantum dots

In this article, we have systematically probed the effect of Cu-doping in CdS quantum dots (QDs) to enhance the photovoltaic performance of the quantum dot-sensitized solar cells (QDSSCs). The Cu-doped CdS photoanodes were prepared by successive ionic layer adsorption and reaction (SILAR) method and the corresponding cell devices were fabricated using CuS counter electrodes with a polysulfide electrolyte. The photovoltaic performance results demonstrate that 3mM Cu-doped CdS QDs based QDSSCs exhibit the efficiency (η) of 3% including JSC=9.40mAcm−2,VOC=0.637V, FF=0.501, which are higher than those with bare CdS (η=2.05%, JSC=7.12mAcm−2, VOC=0.588V, FF=0.489). The structural, topographical and optical properties of the thin films have been studied with the help of X-ray diffraction pattern (XRD), atomic force microscopy (AFM) and UV–vis spectrophotometer. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements indicate that Cu-dopant can inhibit the charge recombination at the photoanode/electrolyte interface and extend the lifetime of electrons. These results reveal that incorporation of copper metal in CdS QDs is a simple and effective method to improve the photovoltaic properties of QDSSCs.

Hierarchical ZnO nanorod-on-nanosheet arrays electrodes for efficient CdSe quantum dot-sensitized solar cells

Two-dimensional (2D) ZnO nanosheet arrays were prepared via vanadium (V)-doping assisted hydrothermal method, and then the nanosheet was successfully converted to a nanorod-on-nanosheet ZnO hierarchical structure by treating with Na2S solution and subsequent hydrothermal reaction. Hierarchical films with different nanorod growth time (1–8 h) were prepared and their photovoltaic properties were also investigated after electrodeposition of CdSe quantum dots. For the hierarchical nanorod-on-nanosheet ZnO films, increasing the ZnO nanorod growth time can enormously enlarge the length of branched nanorods and light-scattering ability, resulting in better light-harvesting efficiency and higher photo-generated electron concentration, which leads to higher short-circuit current density ( J sc) and open-circuit voltage ( V oc). However, further increasing nanorod growth time to 8 h leads to the over-dense coverage of nanorods, which is harmful for light-harvesting efficiency and leads to severe electron recombination, eventually diminishes the power conversion efficiency (PCE). With the optimized nanorod modification and Cu2S counter electrode, the PCE reaches a maximum value of 4.26%, which to the best of our knowledge, is among the highest PCE record for CdSe sensitized solar cells based on ZnO photoanodes.

Designing Three-Dimensional Nanowire Arrays As Efficient Counter Electrodes for Quantum-Dot-Sensitized Solar Cells

Quantum-dot-sensitized solar cell (QDSSC) has been considered as an alternative to new generation photovoltaics, but it still presents very low conversion efficiency. Besides the continuous effort on improving photoanodes and electrolytes, the focused investigation on charge transfer at interfaces and rational design for counter electrodes are recently receiving much attention. Rationally designing nanostructures aiming at solving the critical issues on counter electrodes would be possible to shed light on how to break through the conversion efficiency record of QDSSCs and push this field to move forward. In this presentation, the effort in this group on designing new nanostructures as efficient counter electrodes for QDSSCs will be discussed. For example, tunnel junction arrays configured with degenerate n-type tin-doped indium oxide nanowire (ITO) core and degenerate p-type Cu2S nanocrystal shell (ITO@Cu2S) was designed and fabricated as new efficient counter electrode for QDSSCs. ITO nanowire array core provided a three dimensional conductive network. ITO core and Cu2S nanocrystal shell formed effective tunnel junctions with carrier transport path shorter than 100 nm. It was found that sheet resistance (Rh) was not only dependent on the electron conductivity of the substrate but also related to the semiconductor-electrode interface between CTO and catalysts. The high-quality tunnel junctions resulted in the considerable decrease in Rh of the device, and facilitated electron transfer from CTO to Cu2S. Moreover, the chemical inert nature of ITO made this type of counter electrode stable in liquid electrolyte with no intrinsic issue like copper dissolution in state-of-the-art Cu/Cu2S counter electrode. Compared with planar structures, the three-dimensional nanowire arrays presented higher surface area and easy accessibility of electrolyte, leading to higher catalytic activity of counter electrode as evidenced by apparently decreased charge transfer resistance. As a result, the power conversion efficiency of QDSSCs with the designed ITO@Cu2S nanowire counter electrodes increased by 84.5% and 33.5% compared to that with Au and Cu2S counter electrodes, respectively.[1] Furthermore, the influence of the interface of ITO/Cu2S on the conversion efficiency of QDSSCs was further investigated by using different synthetic route and the following post-treatment to fabricate the ITO@Cu2S nanowire counter electrodes.[2] More interestingly, the hierarchical ITO@Cu2S nanowire arrays were further fabricated and found to be able to further reduce the sheet resistance and charge transfer resistance between the electrolyte and the counter electrode. As a result, the QDSSCs with smaller series resistance, larger shunt resistance and thus the power conversion efficiency of over 6% has been achieved by using this kind of hierarchical ITO@Cu2S nanowire arrays as counter electrodes.[3] Finally, by combining a newly-developed high quality ∼4 nm Cd-, Pb-free Zn-Cu-In-Se alloyed QDs and a new three-dimensional counter electrode, we have achieved QDSSCs with a record certified efficiency of 11.6%.

3D Graphene Frameworks with Uniformly Dispersed CuS as an Efficient Catalytic Electrode for Quantum Dot-Sensitized Solar Cells

Three-dimensional (3D) graphene frameworks (GFs) loading CuS nanocrystals composite (GFs–CuS) are prepared by an in-situ hydrothermal process. We find that 3D graphene frameworks exhibit an excellent supporter for even growth and good distribution of CuS nanocrystals. Such 3D architecture composite could provide multi-direction channels that greatly facilitate electron transport and ion diffusion as well as offer more accessible catalytic active sites. These intrinsic factors are essential for an efficient counter electrode (CE) of quantum dot-sensitized solar cells (QDSSCs). As expected, the CdS/CdSe QDSSCs based on GFs-CuS CE achieves a high power conversion efficiency of 5.04%, which is higher than those of the traditional Pt CE (3.18%), GFs CE (3.60%) and CuS CE (3.75%), even better than 2D graphene–CuS composite CE (4.17%). The electrochemical impedance spectra and Tafel polarization curve analysis reveal that the 3D GFs–CuS composite counter electrode exhibits the lower charge-transfer resistance, faster ion diffusion ability and the higher electrocatalytic activity in comparison with the Pt, GFs, CuS and 2D graphene–CuS electrodes. Furthermore, the GFs–CuS CE exhibits excellent stability, demonstrating its promising potential application as effective counter electrode material in QDSSCs.

A new probe into thin copper sulfide counter electrode with thickness below 100 nm for quantum dot-sensitized solar cells

Currently, most of CuS counter electrodes (CEs) used in quantum dot-sensitized solar cells (QDSSCs) are provided with a thickness of hundreds of nanometers or even several microns. Considering the CE with low thickness having many advantages, thin CuS films with thickness ranging from 47nm below to 115nm have been synthetized in this paper via chemical bath deposition (CBD) method with different bath concentrations. A power conversion efficiency (PCE) of 3.25% has been achieved utilizing CuS thin films a thickness of only 64nm as CEs in QDSSCs without any structural optimization, which is higher than the value of the cell employing CuS CE with thickness of 2.8μm. Electrochemical impedance spectroscopy, Tafel polarization, and two-point current-voltage measurements are used to investigate the electrocatalytic and conductive performance of CuS CEs with different thickness. Owing to the highest electrocatalytic capacity and good conductivity of the 64 nm-thick CuS CE, QDSSC assembled with this CE has reached relatively high PCE under one sun illumination (100mWcm−2, AM 1.5). In addition, cyclic voltammetry measurements indicate that the thin CuS CE has a good stability against the polysulfide electrolyte.

Ternary CuBiS2 nanoparticles as a sensitizer for quantum dot solar cells

This work investigates the synthesis and application in solar cells of a novel solar absorber material CuBiS2. Ternary copper chalcogenide CuBiS2 nanoparticles were grown on a mesoporous TiO2 electrode by the chemical bath deposition (CBD) method. The synthesized CuBiS2 nanoparticles, size 5–10nm, have an energy gap Eg of 2.1eV. Liquid-junction quantum dot-sensitized solar cells were fabricated from the CuBiS2-sensitized electrode using a polysulfide electrolyte. Three types of counter electrodes (CEs) – Pt, Au and Cu2S – were tested. The photovoltaic performance depends on the CBD reaction time and the CE. The best cell, obtained with the Cu2S CE, exhibited the photovoltaic performance of a short-circuit current density Jsc of 6.87mA/cm2, an open-circuit voltage Voc of 0.25V, a fill factor FF of 36% and a power conversion efficiency η of 0.62%. The present work demonstrates the feasibility of CuBiS2 as a solar energy material.

Preparation of high-efficiency CdS quantum-dot-sensitized solar cells based on ordered TiO2 nanotube arrays

Highly ordered TiO2 nanotube arrays are synthesized and utilized in preparing front-side illuminated photoelectrodes of CdS quantum-dot-sensitized solar cells (QDSSCs). The CdS quantum dots (QDs) are adsorbed on the ordered TiO2 nanotube arrays by successive ionic layer adsorption and reaction method (SILAR). Taking the advantages of high surface area and large size of ordered pores of the TiO2 nanotube arrays, the reaction solutions for SILAR processes can easily penetrate into the photoelectrodes; and the formed CdS QDs can be homogeneously dispersed on the TiO2 nanotube walls with high coverage. In order to improve photovoltaic performance of QDSSCs, the other important components including counterelectrode, polysulfide (S2−/Sx2-) electrolyte, and cycles of SILAR processes for preparing CdS QDs sensitized photoelectrodes are optimized. With thermally treated CuS counterelectrode, pure deionized water based polysulfide (S2−/Sx2-) electrolyte, and 15 cycles of SILAR processes prepared CdS QDs sensitized photoelectrode, the QDSSC can achieve the highest power conversion efficiency about 3.22% under full sunlight illumination (100mWcm−2, AM 1.5G), which is a comparative value among the pure CdS QDs sensitized solar cells.

Fabricating CuS counter electrode for quantum dots-sensitized solar cells via electro-deposition and sulfurization of Cu2O

CuS/FTO counter electrode (CE) with flower-like nonosheets structure was fabricated through electro-deposition of Cu2O followed by sulfurization. This electrochemical method has better control over the morphology of CuS/FTO CE. And the application of FTO can avoid the continuous corrosion of Cu substrate in polysulfide electrolyte. Besides, through the optimization of electro-deposition, the CuS/FTO CE obtains excellent photoelectrochemical performance (photoelectric conversion efficiency (PCE)=4.07%, fill factor (ff)=0.50) which is much higher than Pt CE (PCE=1.90%) and Cu2S/Cu CE (PCE=3.76%) prepared by directly immersing copper into polysulfide electrolyte. Therefore, the CuS/FTO CE prepared by electro-deposition of Cu2O followed by sulfurization has shown much promise.

Quantum dot-sensitized solar cells having 3D-TiO2 flower-like structures on the surface of titania nanorods with CuS counter electrode.

The photovoltaic performance of a quantum dot (QD)-sensitized solar cell consisting of CdS/CdSe/ZnS QDs loaded onto the surface of the three-dimensional (3D) flower-like TiO2 structure grown on an array (1D) of TiO2 nanorods (FTiR) is studied. The flower-like structure on the rod-shaped titania was synthesized using a double-step hydrothermal process. The FTiR array exhibited a 3D/1D composite structure with a specific surface area of 81.87 m2/g. Using CuS as the counter electrode instead of Pt offers the best performance and leads to an increase in the conversion efficiency (η). The efficiency of the CdS/CdSe/ZnS QD-loaded FTiR assembling CuS counter electrode cell improved from η = 2.715% (Voc = 0.692 V, Jsc = 5.896 mA/cm2, FF = 0.665) to η = 0.703% (Voc = 0.665 V, Jsc = 2.108 mA/cm2, FF = 0.501) for the QD-loaded FTiR assembling Pt counter electrode cell. These studies reveal a synergistically beneficial effect on the solar-to-current conversion of these QD-sensitized solar cells when a CuS counter electrode is used instead of the usual Pt counter electrode.

Three-dimensional TiO2/ZnO hybrid array as a heterostructured anode for efficient quantum-dot-sensitized solar cells.

The development of a novel nanoarray photoanode with a heterostructure on a transparent conducting oxide substrate provides a promising scheme to fabricate efficient energy conversion devices. Herein, we successfully synthesize the vertically aligned hierarchical TiO2 nanowire/ZnO nanorod or TiO2 nanowire/ZnO nanosheet hybrid arrays, which are proven to be excellent anode candidates for superior light utilization. Consequently, the quantum-dot-sensitized solar cells based on such hybrid arrays exhibit an impressive power conversion efficiency (PCE) under AM 1.5G one sun illumination with improved short-circuit current density (JSC) and fill factor compared to pristine TiO2 nanowire arrays. Combined with the chemical-bath-deposited Cu2S counter electrode, the eventual PCE can be further optimized to as high as 4.57% for CdS/CdSe co-sensitized quantum dot solar cells.

Formation and Characterization of Pb<sub>x</sub>Cd<sub>1-x</sub>S Interlayer for PbS/CdS/ZnS Quantum Dots Sensitized Solar Cells

PbxCd1-xS quantum dots (QDs) was successfully deposited on TiO2 mesoporous film as TiO2 mesoporous photoanode using successive ionic layer adsorption and reaction (SILAR) method for quantum dot sensitized solar cells (QDSSCs). Quantum dot sensitized solar cells (QDSSCs) were prepared by sandwiching the TiO2 mesoporous photoanode with Cu2S counter electrode. Single layer of PbxCd1-xS, PbS and CdS and multilayer of PbS/CdS/ZnS as well as multilayer PbS/PbxCd1-xS/CdS/ZnS were prepared for characterizations. The characterizations including X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscopy (FESEM), UV-visible spectrophotometer and Current-density voltage (J-V) measurement were carried out to study the effects of number of SILAR cycles of PbxCd1-xS interlayer for molar fraction, x of 0.2 in QDSSCs. PbxCd1-xS interlayer with four SILAR cycles is incorporated between PbS and CdS layer will increase the efficiency in QDSSCS.

Enhanced photovoltaic performance and time varied controllable growth of a CuS nanoplatelet structured thin film and its application as an efficient counter electrode for quantum dot-sensitized solar cells via a cost-effective chemical bath deposition.

For the first time we report a simple synthetic strategy to prepare copper sulfide counter electrodes on fluorine-doped tin oxide (FTO) substrates using the inexpensive chemical bath deposition method in the presence of hydrochloric acid (HCl) at different deposition times. CuS nanoplatelet structures were uniformly grown on the FTO substrate with a good dispersion and optimized conditions. The growth process of the CuS nanoplatelets can be controlled by changing the deposition time in the presence of HCl. HCl acts as a complexing agent as well as improving S(2-) concentration against S atoms in this one-step preparation. The photovoltaic performance was significantly improved in terms of the power conversion efficiency (PCE), short-circuit density (J(sc)), open-circuit voltage (V(oc)), and the fill factor (FF). The optimized deposition time of CuS 60 min resulted in a higher PCE of 4.06%, J(sc) of 12.92 mA cm(-2), V(oc) of 0.60 V, and a FF of 0.52 compared to CuS 50 min, CuS 70 min, and a Pt CE. The superior performance of the 60 min sample is due to the greater electrocatalytic activity and low charge transfer resistance at the interface of the CE and the polysulfide electrolyte. The concentration of Cu/S also had an important role in the formation of the CuS nanoplatelet structures. The optical bandgaps for the CuS with different morphologies were measured to be in the range of 1.98-2.28 eV. This improved photovoltaic performance is mainly attributed to the greater number of active reaction sites created by the CuS layer on the FTO substrate, which results large specific surface, superior electrical conductivity, low charge transfer resistance, and faster electron transport in the presence of HCl. Cyclic voltammetry, electrochemical impedance spectroscopy and Tafel-polarization measurements were used to investigate the electrocatalytic activity of the CuS and Pt CEs. This synthetic procedure not only provides high electrocatalytic activity for QDSSCs but could also be a cost-effective way to fabricate flexible electrodes in dye-sensitized solar cells or supercapacitor applications.

Highly efficient and stable quantum dot-sensitized solar cells based on a Mn-doped CuS counter electrode

A maximum efficiency of 5.46% was achieved with low thickness of 10% Mn–CuS counter electrode.

Cost-effective and morphology controllable PVP based highly efficient CuS counter electrodes for high-efficiency quantum dot-sensitized solar cells.

Currently, copper sulfide (CuS) is the most commonly used counter electrode (CE) in high-efficiency quantum dot-sensitized solar cells (QDSSCs) because of its superior electrocatalytic activity in the presence of polysulfide electrolyte. For the first time, CuS thin films were prepared by a facile chemical bath deposition method with different concentrations of polyvinylpyrrolidone (PVP) and directly used as CEs in QDSSCs without any further post treatment. The quantum dot photoanode with the optimized 0.25 mM PVP-based CuS CE exhibits higher short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) of 17.57 mA cm(-2), 0.578 V, 0.514, and 5.22%, respectively, which are much higher values than those of a bare CuS CE (Jsc: 12.36 mA cm(-2); Voc: 0.591 V; FF: 0.436; PCE: 3.18%) and Pt CE (Jsc: 11.25 mA cm(-2); Voc: 0.464 V; FF: 0.296; PCE: 1.54%) under one-sun illumination (AM 1.5 G, 100 mW cm(-2)). Moreover, the 0.25 mM PVP-based CuS CE produces a charge-transfer resistance of only 4.39 Ω with the aqueous polysulfide electrolyte commonly applied in QDSSCs. This value is several orders of magnitude lower than that of a typical Pt electrode (69.75 Ω) and bare CuS electrode (9.27 Ω). This enhancement is mainly attributed to the improved morphology of the 0.25 mM CuS CE with high catalytic activity, which plays a main role in the reduction processes of the oxidized polysulfide electrolyte, as well as the increased sulfur atomic percentage with Cu vacancies. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization were performed to study the underlying reasons behind the efficient CE performance.

Graphite powder film-supported Cu2S counter electrodes for quantum dot-sensitized solar cells

A graphite powder (GP) film-supported Cu2S counter electrode (CE) has been prepared by an accessible and low-temperature method.