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TiO2 hierarchical nanowire-P25 particulate composite photoanodes in combination with N-doped mesoporous carbon/Ti counter electrodes for high performance quantum dot-sensitized solar cells
摘要： The time-consuming transport of photo-generated electrons across conventional photoanode film, composed of disordered P25 TiO2 nanoparticulates, is one of the main bottlenecks to improve the performance of quantum dot-sensitized solar cells (QDSCs). A convenient and effective method was developed for the preparation of high performance photoanodes based on composite paste composed of conventional P25 TiO2 nanoparticulates and TiO2 hierarchical nanowires (HNW) for QDSCs. The shortened transport path in the composite photoanode brings forward suppressed charge recombination processes at the interfaces between photoanode and electrolyte, and improved photovoltaic performance of the resulting solar cells. Through optimizing the composite photoanode and the adoption of N-doped mesoporous carbon/Ti counter electrodes, average power conversion efficiency of Zn-Cu-In-Se (ZCISe) QDSCs was increased from 12.77% corresponding to conventional P25 photoanodes to 13.43% (Jsc = 27.38 mA cm?2, Voc = 0.764 V, and FF = 0.642) corresponding to photoanodes with HNW/P25 weight ratio of 0.1%. Furthermore, this composite photoanode is also effective in improving the photovoltaic performance of QDSCs under different QD sensitizers (such as Zn-Cu-In-S (ZCIS) QDs) as well as different counter electrodes (such as Cu2S/brass).
关键词： TiO2 hierarchical nanowires,Quantum dot-sensitized solar cells,Composite photoanode,High efficiency
更新于2025-09-16 10:30:52
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Aqueous synthesis of Mn-doped CuInSe <sub/>2</sub> quantum dots to enhance the performance of quantum dot sensitized solar cells
摘要： Herein, we present the direct aqueous synthesis of manganese (Mn) doped CuInSe2 (Mn-CISe) quantum dots (QDs) under microwave irradiation to improve the photochemical properties of solar cells. As a result of Mn doping, the narrower bandgap energy of Mn-CISe leads to higher visible light absorption. The Mn-CISe QDs are therefore used as photosensitizers in quantum dot sensitized solar cells (QDSSCs), exhibiting enhanced performance which is dependent on Mn concentration. To the best of our knowledge, this is the ?rst time to construct an Mn-CISe sensitized-TiO2 photoanode to boost the photovoltaic performance of QDSSCs. The incorporation of Mn into CISe increases short-circuit current, which is ascribed to the e?ective injection of the excited electrons from QDs into TiO2 and the consequent higher electron lifetime, likely through a newly formed Mn midgap in the CISe band structure. Compared to the undoped QDs, Mn-CISe QDSSCs show a shorter electron transport time (τt) and a longer electron recombination time (τr) which are studied by intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy, respectively. In fact, a combination of higher light-harvesting e?ciency, slower charge recombination, and a longer electron lifetime gives rise to a maximum photovoltaic performance of 6.28%.
关键词： aqueous synthesis,Mn-doped CuInSe2,quantum dots,photovoltaic performance,quantum dot sensitized solar cells
更新于2025-09-12 10:27:22
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Nanostructured Ni-doped CuS thin film as an efficient counter electrode material for high-performance quantum dot-sensitized solar cells
摘要： High electrocatalytic activity and low charge transfer resistance are the key factors of coutner electrodes (CEs) for high-performance quantum dot-sensitized solar cells (QDSSCs). Hence, it is challenging and highly deisrable to fabricate the CEs with high catalytic activity and low charge transfer resistance for QDSSCs. To address these issues, here, we design and prepare a new catalytic electrode by doping of nickel (Ni) ion in CuS for use as CEs in QDSSCs. The Ni-doped CuS CEs are fabricated via a facile chemcial bath deposition method. Scanning electron microscope study reveals that the Ni-doped CuS exhibits the surface morphology of nanoparticles over nanoflake structrues, while the CuS delivers the nanoflake structures. The Ni-doped CuS provides abundant active sites for reduction of polysulfide redox couple, higher electrical conductivity and offers excellent pathways for electron transfer, which yields the high electrocatalytic activity and delivers the lower charge transfer resistance at the interface of CE/electrolyte. As a result, the TiO2/CdS/CdSe QDSSCs with Ni–CuS yield a power conversion efficiency (η) of 4.36% with short circuit current density (JSC) of 13.78 mA cm?2, open-circuit voltage (VOC) of 0.567 V, and fill factor (FF) of 0.558, which are much superior to that of device with CuS CE (η = 3.24%; JSC = 10.63 mA cm?2; VOC = 0.567; FF = 0.546) under one sun illumination (AM 1.5G, 100 mW cm?2). Present work determines that Ni-doped CuS could be a promising CE material for QDSSCs due to its high electrical conductivity, excellent electrocatalytic activity, and lower charge transfer resistance.
关键词： Charge transfer resistance,Nanostructured Ni-doped CuS,Quantum dot-sensitized solar cells,Counter electrode,Electrocatalytic activity
更新于2025-09-12 10:27:22
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Copper sulfide/ cuprous selenide as a new counter electrode for quantum-dot-sensitized solar cells
摘要： In this paper, the copper sulfide/copper selenide (Cu2S/Cu2Se) composite is presented as a new counter electrode (CE) in the quantum-dot-sensitized solar cells (QDSSCs), for the first time. This novel CE shows a higher electrocatalytic performance towards the polysulfide electrolyte. The obtained results show that, with the change of the CE material from the CuS to the (Cu2S/Cu2Se) composite, the short-circuit current and the cell efficiency are increased from 7.22 to 19.18 mA/cm2 and 1.36 to 4.60%, respectively. The electrochemical impedance spectroscopy (EIS) study and the Tafel polarization analysis demonstrate that the (Cu2S/Cu2Se) CE shows a lower charge transfer resistance in the electrolyte–CE interface, 6.2 ? for the (Cu2S/Cu2Se (5)) CE, in comparison with the pure Cu2S CE, 142.1 ?.
关键词： Cuprous selenide,Copper sulfide,Electrocatalytic performance,Counter electrode,Quantum-dot-sensitized solar cells
更新于2025-09-12 10:27:22
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Bandgap Tunable Ternary Cd <sub/><i>x</i> </sub> Sb <sub/> 2– <i>y</i> </sub> S <sub/>3?δ</sub> Nanocrystals for Solar Cell Applications
摘要： We report the synthesis and photovoltaic performance of a new nonstoichiometric ternary metal sulfide alloyed semiconductor?CdxSb2?yS3?δ nanocrystals prepared by the two-stage sequential ionic layer adsorption reaction technique. The synthesized CdxSb2?yS3?δ nanocrystals retain the orthorhombic structure of the host Sb2S3 with Cd substituting a fraction (x = 0?0.15) of the cationic element Sb. The CdxSb2?yS3?δ lattice expands relative to the host, Sb2S3, with its lattice constant a increasing linearly with Cd content x. Optical and external quantum efficiency (EQE) spectra revealed that the bandgap Eg of CdxSb2?yS3?δ decreased from 1.99 to 1.69 eV (i.e., 625?737 nm) as x increased from 0 to 0.15. Liquid-junction CdxSb2?yS3?δ quantum dot-sensitized solar cells were fabricated using the polyiodide electrolyte. The best cell yielded a power conversion efficiency (PCE) of 3.72% with the photovoltaic parameters of Jsc = 15.97 mA/cm2, Voc = 0.50 V, and FF = 46.6% under 1 sun. The PCE further increased to 4.86%, a respectable value for a new solar material, under a reduced light intensity of 10% sun. The PCE (4.86%) and Jsc (15.97 mA/cm2) are significantly larger than that (PCE = 1.8%, Jsc = 8.55 mA/cm2) of the Sb2S3 host. Electrochemical impedance spectroscopy showed that the ZnSe passivation coating increased the electron lifetime by three times. The EQE spectrum of CdxSb2?yS3?δ has a maximal EQE of 82% at λ = 350 nm and covers the spectral range of 300?750 nm, which is significantly broader than that (300?625 nm) of the Sb2S3 host. The EQE-integrated current density yields a Jph of 11.76 mA/cm2. The tunable bandgap and a respectable PCE near 5% suggest that CdxSb2?yS3?δ could be a potential candidate for a solar material.
关键词： ternary metal sulfide,CdxSb2?yS3?δ nanocrystals,photovoltaic performance,quantum dot-sensitized solar cells,bandgap tunable
更新于2025-09-12 10:27:22
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Improved light-harvesting and suppressed charge recombination by introduction of a nanograss-like SnO <sub/>2</sub> interlayer for efficient CdS quantum dot sensitized solar cells
摘要： Quantum dot sensitized solar cell (QDSSC) performance is primarily limited by the recombination of charges at the interfaces of TiO2/quantum dot (QD) sensitizer/electrolyte. Hence, blocking or suppressing the charge recombination is an essential requirement to elevate the QDSSC performance to the next level. To retard the charge recombination, herein, we propose the introduction of a SnO2 nanograss (NG) interlayer on the surface of TiO2 using the facile chemical bath deposition method. The SnO2 NG interlayer not only inhibits the interfacial recombination processes in QDSSCs but also enhances the light-harvesting capability in generating more excitons. Hence, the TiO2/SnO2 NG/CdS QDSSCs can achieve the power conversion efficiency of 3.15%, which is superior to that of a TiO2/CdS device (2.16%). Electrochemical impedance spectroscopy, open-circuit voltage decay and dark current analyses confirm that the photoanode/electrolyte interface is suppressed and the life time is improved by introducing the SnO2 NG interlayer between the TiO2 and CdS QD sensitizer.
关键词： Charge recombination,SnO2 nanograss,Light-harvesting,Chemical bath deposition,Quantum dot sensitized solar cells
更新于2025-09-12 10:27:22
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Development of solid polymer electrolytes based on sodium-carboxymethylcellulose (NaCMC)-polysulphide for quantum dot-sensitized solar cells (QDSSCs)
摘要： Sodium-carboxymethylcellulose (NaCMC) films have been developed by solution casting technique. The films were soaked into an optimized aqueous polysulphide electrolyte containing 4 M sodium sulphide (Na2S) and 1 M sulphur (S). The optimized aqueous polysulphide electrolyte has the ambient conductivity of (1.46 ± 0.02) × 10-1 S cm-1. The NaCMC films were soaked for different durations of 30, 60, 68 and 75 s. The highest room temperature ionic conductivity (RTIC) of (2.79 ± 0.09) × 10-5 S cm-1 is exhibited by NaCMC film soaked in polysulphide electrolyte for 68 s. The conductivity-temperature relationship of NaCMC-based polysulphide solid polymer electrolytes (SPEs) follows the Arrhenius rule. The highest conducting SPE exhibits the lowest activation energy (EA) value of 0.38 eV. Ionic coefficient of diffusion (D), ionic mobility (μ) and free ions concentration (n) of the SPEs were determined. The newly developed SPEs are used as electrolyte in quantum dot-sensitized solar cells (QDSSCs) application with the configuration FTO/TiO2/CdS/ZnS/SPE/Pt/FTO. Under 1000 W m-2 illumination, QDSSC with CMC-68 SPE exhibits the highest power conversion efficiency (PCE) of 0.90%. The values of short circuit current (JSC) and PCE are closely related to electron lifetime and recombination rate.
关键词： Solid polymer electrolyte,Sodium-carboxymethylcellulose,Quantum dot-sensitized solar cells,Transport properties,Polysulphide
更新于2025-09-11 14:15:04
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Effect of CuS nanocrystalline particles on counter electrodes of multi-wall carbon nanotubes for QDSCs
摘要： CuS nanocrystalline particles are deposited into the acid-treated multi-wall carbon nanotubes (MWCNTs) film on the fluorine-doped tin oxide glass substrate through the successive ionic layer adsorption and reaction combined with spin-coating technology to form MWCNTs/CuS composite counter electrode (CE). The CuS adding amount is changed in different cycles to discuss its effect mechanism on the photoelectric properties of MWCNTs/CuS composite CE based quantum dot sensitized solar cells (QDSCs). The TiO2 photoanodes are prepared by the electrospinning technique with CdS and ZnS as co-sensitizer. QDSCs are assembled with photoanodes, the polysulfide electrolyte and abovementioned CEs. The CEs are characterized by X-ray diffraction, transmission electron microscope and energy dispersed X-ray detector, which verifies CuS nanocrystalline particles are attached to MWCNTs successfully. The photoelectric properties are analyzed by Nyquist, Tafel and J–V curves. The results show that the introduction of CuS nanocrystalline particles can promote reduction rate of polysulfide species and the short circuit current density (Jsc) to improve catalytic activity, leading to a higher power conversion efficiency (PCE). The MWCNTs based CE with deposition CuS in eight cycles exhibits the best photoelectric performance within all CE samples and the electrical conductivity of MWCNTs/8CuS CE is superior to that of Pt CE according to Nyquist and Tafel curve analysis. PCE of QDSCs with MWCNTs/8CuS CE is up to 5.186%, which is a little lower than that of Pt CE (5.250%), but it possesses a higher Jsc value (18.028?mA cm?2) than that of Pt CE (16.057?mA cm?2). The low-cost MWCNTs/CuS composite CE with simple preparation is more suitable than Pt CE for commercial application of QDSCs.
关键词： multi-wall carbon nanotubes,quantum dot sensitized solar cells,CuS nanocrystalline particles,photoelectric properties,counter electrode
更新于2025-09-10 09:29:36