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Synthesis of ZnxCd1-xSe@ZnO Hollow Spheres in Different Sizes for Quantum Dots Sensitized Solar Cells Application
摘要： ZnxCd1-xSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnxCd1-xSe@ZnO HS could be tuned from ~300 nm to ~800 nm using ZnO HS pre-synthesized by different sizes of carbonaceous spheres as templates. The photovoltaic performance of QDSSCs, especially the short-circuit current density (Jsc), experienced an obvious change when different sizes of ZnxCd1-xSe@ZnO HS are employed. The ZnxCd1-xSe@ZnO HS with an average size distribution of ~500 nm presented a better performance than the QDSSCs based on other sizes of ZnxCd1-xSe@ZnO HS. When using the mixture of ZnxCd1-xSe@ZnO HS with different sizes, the power conversion ef?ciency can be further improved. The size effect of the hollow spheres, light scattering, and composition gradient structure ZnxCd1-xSe@ZnO HS are responsible for the enhancement of the photovoltaic performance.
关键词： zinc oxide,alloyed quantum dots,sensitized solar cells,hollow spheres
更新于2025-11-14 17:04:02
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The Size Effect of TiO2 Hollow Microspheres on Photovoltaic Performance of ZnS/CdS Quantum Dots Sensitized Solar Cell
摘要： Size controllable TiO2 hollow microspheres (HMS) were synthesized by a carbonaceous spheres (CS) template method. Based on TiO2 HMS, the ZnS/CdS quantum dots (QDs) were loaded to form a ZnS/CdS@TiO2 HMS photoanode for quantum dots sensitized solar cell (QDSSC). The size effects of TiO2 HMS on photovoltaic performance were investigated, and showed that TiO2 HMS with sizes ~560 nm produced the best short-circuit current density (Jsc) of 8.02 mA cm?2 and highest power conversion efficiency (PCE) of 1.83%, showing a better photovoltaic performance than any other QDSSCs based on TiO2 HMS with size ~330 nm, ~400 nm, and ~700 nm. The improvement of photovoltaic performance based on ~560 nm TiO2 HMS which can be ascribed to the enhanced light harvesting efficiency caused by multiple light reflection and strong light scattering of TiO2 HMS. The ultraviolet-visible (UV-vis) spectra and incident photo to the current conversion efficiency (IPCE) test results confirmed that the size of TiO2 HMS has an obvious effect on light harvesting efficiency. A further application of ~560 nm TiO2 HMS in ZnS/PbS/CdS QDSSC can improve the PCE to 2.73%, showing that TiO2 HMS has wide applicability in the design of QDSSCs.
关键词： titanium dioxide,quantum dots sensitized solar cells,hollow microspheres
更新于2025-11-14 17:04:02
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Wavefunction engineering for efficient photoinduced-electron-transfer in CuInS2 quantum dots sensitized solar cells
摘要： The high-efficiency of quantum dots (QDs) sensitized solar cells benefits from the highly efficient photoinduced-electron-transfer (PET) to external electrodes. Here, we investigated how the efficiency of the PET. Though the electron trapping can be suppressed after the ZnS surface surface defects and conduction-band (CB) offsets between core and shell materials affect the PET from CuInS2 QDs by means of time-resolved femtosecond transient-absorption and nanosecond photoluminescence spectroscopy. The transfer of 1S excited electrons from CuInS2 QDs to TiO2 films is demonstrated and we find that the surface electron-trapping can significantly reduce the efficiency of CuInS2 QDs sensitized solar cells. CB offset, which allows us to achieve a quasi-type II carrier confinement in CuInS2/CdS core/shell QDs because of their low electron-density at QD surface. The surface delocalization of electron wavefunction from CuInS2 core to CdS shell. Finally, we demonstrate that these new mechanistic understandings of the PET processes are of great crucial for improving the efficiency of CuInS2 QDs sensitized solar cells.
关键词： quantum dots sensitized solar cells,photoinduced electron-transfer,quantum dots,CuInS2,wavefunction engineering
更新于2025-09-23 15:19:57
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TiO2 Passivation Layer on ZnO Hollow Microspheres for Quantum Dots Sensitized Solar Cells with Improved Light Harvesting and Electron Collection
摘要： Light harvesting and electron recombination are essential factors that influence photovoltaic performance of quantum dots sensitized solar cells (QDSSCs). ZnO hollow microspheres (HMS) as architectures in QDSSCs are beneficial in improving light scattering, facilitating the enhancement of light harvesting efficiency. However, this advantage is greatly weakened by defects located at the surface of ZnO HMS. Therefore, we prepared a composite hollow microsphere structure consisting of ZnO HMS coated by TiO2 layer that is obtained by immersing ZnO HMS architectures in TiCl4 aqueous solution. This TiO2-passivated ZnO HMS architecture is designed to yield good light harvesting, reduced charge recombination, and longer electron lifetime. As a result, the power conversion efficiency (PCE) of QDSSC reaches to 3.16% with an optimal thickness of TiO2 passivation layer, which is much higher when compared to 1.54% for QDSSC based on bare ZnO HMS.
关键词： TiO2 passivation layer,quantum dots sensitized solar cells,ZnO hollow microspheres
更新于2025-09-23 15:19:57
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S-alkylbenzothiophenium-based solid-state electrolyte for efficient quantum-dot sensitized solar cells
摘要： Developing cost-effective solid-state electrolyte is a urgent issue and a common request for (photo) electrochemical cells. In this work, a series of organic ionic conductors based on the S-substituted benzothiophenium salts have been synthesized via a simple and low-cost method. Research on the thermal behavior, optical absorption and ionic conductivity shows that S-methylbenzothiophenium tetrafluoroborate ([MBT]BF4) among them have the good thermal stability, high ionic conductivity and no absorption in the visible region. And the solid-state electrolyte using [MBT]BF4 as the matrix exhibits the good interfacial compatibility with photoanode. Applying this solid-state electrolyte into the quantum-dot sensitized solar cell (QDSSCs), the device achieves an open circuit voltage of 0.71 V, a short circuit current density of 20.73 mW cm?2, and a power conversion efficiency of 5.49% which is higher than those previously reported for the solid-state QDSSCs.
关键词： Organic ionic conductors,Quantum-dots sensitized solar cells,Solid-state electrolyte,Benzothiophene
更新于2025-09-16 10:30:52
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Doped quaternary metal chalcogenides Cu2ZnSnS4 nanocrystals as efficient light harvesters for solar cell devices
摘要： In this study, we report highly stable photoactive quaternary metal chalcogenide Cu2ZnSnS4 nanocrystals synthesis from low cost, ecofriendly, non-toxic and earth-abundant elements for photovoltaic devices. Their electro-optical properties such as, tunable band gap, high-absorption coefficient and wide absorption window make them highly suitable materials to be utilized as absorber layer and counter electrode in various types of solar cells. For this purpose, first we synthesized Cu2ZnSnS4 nanocrystals by colloidal, co-precipitation, wet chemical and hydrothermal methods using stabilizing agents under variable reaction conditions. Afterwards, hydrothermal method was employed to synthesize nanocrystals of Cu2CoSnS4, Cu2FeSnS4, Cu2SrSnS4 and Cu2NiSnS4 by replacing Zn with Co, Fe, Sr and Ni metals. The UV–Vis absorption spectra indicate the nanocrystals can absorb entire visible region of electromagnetic radiation and their band gaps range from 1.5 to 1.7 eV. The X-ray diffraction (XRD) patterns confirm the formation of kieserite phase of all nanocrystals with a crystallite size of approximately 6–10 nm. These nanocrystals are coated on surface of the synthesized ZnO nanoparticles to study their application as absorbing layer in quantum dots-sensitized solar cells (QDSSCs). Moreover, they were adsorbed on ITO substrate to study their utilization as counter electrode of dye-sensitized solar cells (DSSCs). The solar cells exhibit efficiencies of 1.2–1.8%, which prove the synthesized nanocrystals can perform excellent role as light absorber and counter electrode in any kind of solar cell device.
关键词： solar cell devices,light harvesters,photovoltaic devices,dye-sensitized solar cells,quantum dots-sensitized solar cells,Cu2ZnSnS4 nanocrystals
更新于2025-09-12 10:27:22
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A Layered Photo-Anode Prepared Using TiO <sub/>2</sub> ?Nanocrystals with Different Sizes for Enhanced Light-Trapping in Quantum Dots-Sensitized Solar Cells
摘要： Using TiO2 nanocrystals (NCs) with diameters of 20 nm (T20), 40 nm (T40) and 60 nm (T60) as starting materials, three TiO2 photo-anodes were constructed on FTO glass. Meanwhile, a triple-layered photo-anode was prepared by depositing the T20, the T40, and the T60 layer by layer on FTO glass (T60/T40/T20/FTO/glass). These four kinds of photo-anodes were sensitized with CdZn0.02S0.08Se0.92 QDs by successive ionic layer adsorption and reaction (SILAR). Based on these photo-anodes, four quantum dot-sensitized solar cells (QDSSCs) were ?nally obtained. The results indicated that the highest ef?ciency of 3.95% was obtained in the QDSSC with the triple-layered photo-anode. The short-circuit photocurrent density (Jsc) of the QDSSC with the triple-layered photo-anode was 1.25, 1.21 and 1.13-fold higher than that of the QDSSCs with T20-, T40- and T60-based photo-anode, respectively. Moreover, with the increase of the average size of the TiO2 NCs from 20 to 60 nm, the Jsc increased from 13.8 to 15.24 mA·cm?2. The optical properties, crystal structure and morphologies of the bare TiO2 ?lms and the CdZn0.02S0.08Se0.92 sensitized TiO2 photo-anodes were characterized by UV-Vis spectroscopy, XRD and SEM. The incident photon-to-electron conversion ef?ciency, the open circuit voltage decay and the electrochemical impedance spectroscopy of the QDSSCs were measured and discussed, so as to clarify the underlying mechanism of the property enhancement.
关键词： quantum dots-sensitized solar cells,TiO2 nanocrystals,light-trapping,CdZn0.02S0.08Se0.92 QDs,photo-anode
更新于2025-09-11 14:15:04