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In Situ Microwave-Assisted Fabrication of Hierarchically Arranged Metal Sulfide Counter Electrodes to Boost Stability and Efficiency of Quantum Dot-Sensitized Solar Cells
摘要： This study describes preparation of metal sulfide counter electrodes (CEs) through one-pot microwave-assisted route to improve power conversion efficiency (PCE) of quantum dot-sensitized solar cells at a lower cost. The CuS nanorods, Ni0.96S nanoparticles, and PbS nanocubes are synthesized and deposited in situ on fluorine-doped tin oxide substrate to serve as CEs without further post-treatment. Effects of several reaction parameters including sulfur precursor (Na2S, C2H5NS, CH4N2S), Cu concentration, reaction time, and choice of cation (Cu, Ni, Pb) on the CEs morphology, electrochemical characteristics, and PCE are studied. Furthermore, nanostructure formation and thin film growth are studied and correlated with PCE, from which morphology- and composition-performance relationships can be inferred. Hierarchically assembled nanorod CuS CEs exhibit higher electrochemical stability in the S2–/Sn2– redox reaction. Together with the efficient charge transfer and higher diffusion coefficient of polysulfide redox at the electrode/electrolyte interface, deduced from electrochemical impedance spectroscopy and Tafel analyses, a PCE of 8.32% is achieved for the CuS CE. The enhanced photovoltaic performance is ascribed to the 1D CuS nanorods forming a diffusive structure which decreases charge transfer impedance and facilitates regeneration of polysulfide redox leading to a higher short-circuit current density and fill factor.
关键词： In situ deposition,quantum dot-sensitized solar cells,counter electrode,CuS,microwave-assisted synthesis
更新于2025-11-14 17:04:02
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Hierarchical ZnO microspheres embedded in TiO2 photoanode for enhanced CdS/CdSe sensitized solar cells
摘要： Control of structural and compositional characteristics of photoanodes is a crucial step toward rapid transport of charges and high efficiency loading of dye or quantum dots in case of solar cell application. A hierarchical ZnO microspheres (ZMS) and TiO2 hybrid photoanode film was prepared for improved CdS/CdSe quantum dot sensitized solar cells (QDSCs). The addition of ZMS into TiO2 electrode films resulted in both increased short circuit current density (Jsc) and open circuit voltage (Voc). Such an improvement is ascribed to the increased light harvesting owing to scattering by ZMS and the reduced charge recombination due to the surface modification. TiO2/ZMS hybrid photoanode displays superior charge injection/transport performance due to the ZMS with unique hierarchical structure, providing charge transfer continuity and multiple electron transport channels for timely electron transport. As a result, the Jsc, Voc, and the photovoltaic conversion efficiency (PCE) were all remarkably enhanced with the insertion of hierarchical ZMS though varied appreciably with the amount of ZMS. Thus, the designed TiO2/ZMS heterostructure based QDSCs with an optimizing ZMS ratio of 20 wt% achieved a PCE of 5.99%, which is about 35% increase of the efficiency for the devices without ZMS (4.45%).
关键词： electron transport,ZnO microspheres,charge injection,quantum dot-sensitized solar cells,photoanode,light scattering
更新于2025-11-14 17:04:02
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Surface Plasmon Resonance Enhancement of PbS Quantum Dot-Sensitized Solar Cells
摘要： Lead sulfide (PbS)-sensitized quantum dot solar cells (QDSC) were fabricated using TiO2 and TiO2–Au plasmonic nanocomposite films by successive ionic layer adsorption and reaction (SILAR) method. The average size of gold nanoparticles (GNPs) used for fabricating nanocomposite films was ~ 15 nm. Thin plasmonic QDSC, with a film thickness of 10 μm, showed an increase of ~ 11% in photocurrent and ~ 6% in overall energy conversion efficiency compared to the device without GNPs. The improved performance of QDSCs is attributed to the increased absorption due to the plasmonic near-field effects of the incorporated GNPs. High-efficiency PbS/CdS-co-sensitized thick cells with 16 μm bilayer TiO2 also showed improvement in photocurrent and efficiency. The results show that the plasmonic-enhanced absorption can be used to augment efficiency of QDSC devices in much the same fashion as that of dye-sensitized solar cells.
关键词： Gold nanoparticles,Quantum dot-sensitized solar cells,Plasmonics,Photovoltaics
更新于2025-10-22 19:40:53
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Bi-Exciton Dissociation Dynamics in Nano-Hybrid Au-CuInS <sub/>2</sub> Nanocrystals
摘要： Multiexciton harvesting from semiconductor quantum dot has been a new approach for improving the solar cell efficiency in Quantum Dot Sensitized Solar Cells (QDSC). Till date, relation between multiexciton dissociation in metal?semiconductor nanohybrid system and boosting the power conversion efficiency (PCE) of QDSC were never discussed. Herein we report a detailed spectroscopic investigation of biexciton dissociation dynamics in copper indium sulfide (CuInS2, also referred as CIS) and Au-CIS nanohybrid, utilizing both time-resolved PL and ultrafast transient absorption (TA) techniques. Ultrafast transient absorption suggests the formation of bi-exciton in CIS NCs which efficiently dissociates in Au-CIS nanohybrids. Maximum multiexciton dissociation (MED) efficiency is determined to be ~ 80% at higher laser fluency, however it was observed to be 100% at lower laser fluency. Prior to exciton dissociation electrons are captured by Au NP in the nanohybrid from the conduction band of CIS NCs which is energetically higher than Fermi level of Au. Here we demonstrate the proof-of-concept in multi-electron dissociation which may provide a new approach for improving the efficiency in QDSSCs, where we found power conversion efficiency (PCE) of Au-CIS nanohybrids up to 2.49% as compared to ~1.06% ~for pure CIS NCs in similar condition. This finding can be an efficient approach towards the design and development of efficient solar cell and optoelectronic devices using the principles of multiexciton generation and extracting multiexcitons in metal-semiconductor nanohybrid system.
关键词： copper indium sulfide,biexciton dissociation dynamics,Quantum Dot Sensitized Solar Cells,power conversion efficiency,ultrafast transient absorption,Multiexciton harvesting,Au-CIS nanohybrid
更新于2025-09-23 15:21:21
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Effect of PbS quantum dot-doped polysulfide nanofiber gel polymer electrolyte on efficiency enhancement in CdS quantum dot-sensitized TiO2 solar cells
摘要： Quantum dot-sensitized solar cells (QDSSCs) are among the most promising low cost third generation solar cells. Semiconductor quantum dots have unique properties such as high molar extinction coefficients, tunable energy gap by the quantum confinement effect and the ability of multiple exciton generation. In this study, stable CdS QDSSCs were fabricated by using polysulfide liquid electrolytes and also by using cellulose acetate nanofiber-based gel electrolytes. Incorporation of PbS Q dots to the liquid or gel electrolyte showed a significant enhancement in solar cell efficiency. Under the simulated light of 100 mW cm-1 the efficiency of the polysulfide liquid electrolyte based CdS QD solar cells increased from 1.19% to 1.51% and the efficiency of the nanofibre gel electrolyte based CdS QD solar cells increased from 0.94 % to 1.46% due to the incorporation of 5% (wt/wt) PbS Q dots into the respective electrolytes. The efficiency increase has been attributed to the increase in short circuit photocurrent density due to increased sulfide ion (S2-) conductivity evidently caused by indirect ionic dissociation facilitated by PbS QDs.
关键词： Sulfide ion conductivity,Nanofibre gel electrolyte,Efficiency enhancement,Quantum dot sensitized solar cells,Quantum dot doped electrolyte
更新于2025-09-23 15:21:01
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One-pot fabrication of mesoporous g-C3N4/NiS co-catalyst counter electrodes for quantum-dot-sensitized solar cells
摘要： The nickel sulfide (NiS) nanoparticles were anchored on the mesoporous graphitic carbon nitride (g-C3N4) by one-pot calcination with sulfur powder as sulfur source and pore-forming agent. It is the first attempt to use the g-C3N4/NiS as a counter electrode (CE) for quantum-dot-sensitized solar cells. The g-C3N4/NiS co-catalyst based on 0.74 wt% NiS loading for Sn2- reduction obtained a low interface charge transfer resistance (Rct) of 1.08 Ω. The power conversion efficiency of the QDSSC assembled with ZnSe/CdS/CdSe/ZnSe-sensitized TiO2 photoanode and g-C3N4/NiS CE is up to 5.64%, which is 3.05 times as high as that of pure g-C3N4 CE. The enhancement of cell efficiency is attributed to the synergistic effects of excellent morphology of g-C3N4 and its co-catalysis with NiS nanoparticles. The mesoporous architecture contributes a large specific surface area and fast electrolyte transfer channels, and the coupling of g-C3N4 with NiS promotes the transfer of charge between the interface g-C3N4/NiS and electrolytes. The presented strategy for fabricating mesoporous architecture with g-C3N4/NiS uses low-cost raw materials and a simple preparation method, which provides a feasible route to enhance the electrocatalytic activity of g-C3N4.
关键词： g-C3N4/NiS,electrocatalytic activity,mesoporous architecture,counter electrode,quantum-dot-sensitized solar cells
更新于2025-09-23 15:21:01
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Improvement of Power Conversion Efficiency of Quantum Dot-Sensitized Solar Cells by Doping of Manganese into a ZnS Passivation Layer and Cosensitization of Zinc-Porphyrin on a Modified Graphene Oxide/Nitrogen-Doped TiO <sub/>2</sub> Photoanode
摘要： It is vital to acquire power conversion efficiencies comparable to other emerging solar cell technologies by making quantum dot-sensitized solar cells (QDSSCs) competitive. In this study, the effect of graphene oxide (GO), nitrogen, manganese, and a porphyrin compound on the performance of QDSSCs based on a TiO2/CdS/ZnS photoanode was investigated. First, adding GO and nitrogen into TiO2 has a conspicuous impact on the cell efficacy. Both these materials reduce the recombination rate and expand the specific surface area of TiO2 as well as dye loading, reinforcing cell efficiency value. The maximum power conversion efficiency of QDSSC with a GO N-doped photoelectrode was 2.52%. Second, by employing Mn2+ (5 and 10 wt %) doping of ZnS, we have succeeded in considerably improving cell performance (from 2.52 to 3.47%). The reason for this could be for the improvement of the passivation layer of ZnS by Mn2+ ions, bringing about to a smaller recombination of photoinjected electrons with either oxidized dye molecules or electrolyte at the surface of titanium dioxide. However, doping of 15 wt % Mn2+ had an opposite effect and somewhat declined the cell performance. Finally, a Zn-porphyrin dye was added to the CdS/ZnS by a cosensitization method, widening the light absorption range to the NIR (near-infrared region) (>700 nm), leading to the higher short-circuit current density (JSC) and cell efficacy. Utilizing an environmentally safe porphyrin compound into the structure of QDSSC has dramatically enhanced the cell efficacy to 4.62%, which is 40% higher than that of the result obtained from the TiO2/CdS/ZnS photoelectrode without porphyrin coating.
关键词： graphene oxide,nitrogen doping,manganese doping,quantum dot-sensitized solar cells,cosensitization,Zn-porphyrin,power conversion efficiency
更新于2025-09-23 15:21:01
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Effect of co-sensitization of InSb quantum dots on enhancing the photoconversion efficiency of CdS based quantum dot sensitized solar cells
摘要： The effect of co-sensitization of CdS and InSb Quantum Dots (QDs) on the enhancement of efficiency of Quantum Dots Sensitized Solar Cells (QDSSCs) has been investigated. InSb is synthesized by a facile solvothermal method using indium metal particles and antimony trichloride as precursors. From TEM images the average particle size of InSb was found to be less than 25 nm. The I–V data showed photoconversion efficiency (PCE) of 0.8% using InSb QDs as a sensitizer layer for QDSSC. However, co-sensitization of InSb QDs and CdS QDs on the TiO2 photoanode in QDSSCs showed an enhanced PCE of 4.94% compared to that of CdS sensitized solar cells (3.52%). The InSb QD layer broadens the light absorption range with reduced spectral overlap causing an improvement in light harvesting along with suppression of surface defects which reduced the recombination losses. As a result, co-sensitized TiO2/CdS/InSb QDSSC exhibits a greatly improved PCE of 4.94%, which is 40% higher than that of TiO2/CdS (3.52%) based QDSSCs due to improved light absorption with low recombination losses.
关键词： quantum dot sensitized solar cells,co-sensitization,photoconversion efficiency,CdS,InSb quantum dots
更新于2025-09-23 15:19:57
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Application of ZnxLayFezO4 spinel nanomaterial in quantum dot sensitized solar cells
摘要： A novel inorganic spinel nanomaterial with formula Zn0.6093La1.3979Fe0.8650O4 (ZLF) was synthesized and characterized by the X-ray photoelectron spectroscopy (XPS) to determine its stoichiometric formula. The Filed-Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) images displayed that the ZLF nanoparticles (NPs) had a very fine spherical morphology and average particle sizes in the range of about 5–30 nm. Quantum dot-sensitized solar cells (QDSSCs) were fabricated using the ZLF NPs which were incorporated into the TiO2 pastes of photoanodes. The photoluminescence (PL) spectra of the ZLF NPs and the photoanodes exhibited three maxima plus a weak broad peak at around 420, 460 and 485 plus 530 nm. The lowest intensity of the PL peak for the CdSe cell fabricated using 0.4 %ZLF suggested that it had the least charge recombination and the easiest electron transfer. The photovoltaic parameters of the optimized champion cell containing 0.4 % of ZLF NPs (η = 3.50 %, JSC = 13.11 mA/cm2, VOC = 0.58 V) were boosted compared to those of the ZLF-free reference cell (η = 2.18 %, JSC = 8.70 mA/cm2, VOC = 0.57 V) demonstrating a high improvement of approximately 61 % in the efficiency. The Electrochemical Impedance Spectra (EIS) revealed that the charge transfer resistance (RCT) in the optimum cell was dropped by adding the ZLF NPs into the TiO2 compared to that of the reference ZLF-free cell. Thus, upon adding 0.4 %ZLF, appropriate photocurrent efficiency was attained for the QDSSC because the ZLF nanoparticles were used in a minimum amount in order to speed up the electron transport, decline the recombination and enhance the cell efficiency.
关键词： Photoluminescence spectra,Spectra,ZnLaFeO4nanoparticles,Quantum dot sensitized solar cells,Electrochemical impedance (EIS),XPS
更新于2025-09-23 15:19:57
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Poly(acrylamide- <i>co</i> -acrylic acid) gel polymer electrolyte incorporating with water-soluble sodium sulfide salt for quasi-solid-state quantum dot-sensitized solar cell
摘要： Rapid decay of photoanode, leakage from sealant, and evaporation of electrolyte are always the major concerns of quantum dot-sensitized solar cells (QDSCs) based on liquid electrolyte. Subsequently, gel polymer electrolyte (GPE) appears as an attractive solution in addition to lower cost, lighter weight, and flexibility. Poly(acrylamide-co-acrylic acid) (PAAm-PAA) is of special interest to act as a polymer host to entrap liquid electrolyte because it provides high transparency, good gelatinizing properties, and excellent compatibility with the liquid electrolyte. In this work, the electrical and transport properties of PAAm-PAA GPE incorporating with water-soluble sodium sulfide were characterized by impedance spectroscopy. An increment of ionic conductivity was observed with the incorporation of ethylene carbonate (EC) and potassium chloride (KCl). The highest room temperature ionic conductivity of PAAm-PAA GPE is 70.82 mS·cm?1. QDSC based on PAAm-PAA GPE with the composition of 1.3 wt% of KCl, 0.9 wt% of EC, 55.3 wt% of PAAm-PAA, 38.5 wt% of sodium sulfide, and 4.0 wt% of sulfur can present up to 1.80% of light-to-electricity conversion efficiency.
关键词： gel polymer electrolyte,additive,Poly(acrylamide-co-acrylic acid),quantum dot-sensitized solar cells
更新于2025-09-23 15:19:57