Synergistic effect of ZnS outer layers and electrolyte methanol content on efficiency in TiO(2)/CdS/CdSe sensitized solar cells

The effect of methanol content in water based polysulfide electrolytes in TiO(2)/CdS/CdSe quantum dot sensitized solar cells (QDSSCs) prepared by the SILAR method was studied. In addition, the effect of coating the mesoporous QD sensitized films with ZnS outer layers was investigated. Charge recombination reactions were measured using time resolved spectroscopic measurements. These studies reveal a synergistically beneficial effect from using ZnS layers and methanol in the polysulfide electrolyte on the control of charge transfer processes within these devices and ultimately on overall cell performance.     

CdSe量子点敏化纳米二氧化钛太阳电池的电化学交流阻抗谱

量子点敏化纳米TiO2太阳电池(QDSSCs)具有诱人的发展前景,但是与传统的染料敏化太阳电池(DSSCs)相比,其目前的光电转换效率还非常低(仅为3%左右).为了寻找QDSSCs光电转换效率低的原因,本文主要采用外加偏压下的交流阻抗谱技术对通常以S2-/S-x离子对为电解质的CdSe胶体量子点敏化纳米TiO2电极的准...     

Highly efficient CdS quantum dot-sensitized solar cells based on a modified polysulfide electrolyte

A modified polysulfide redox couple, [(CH(3))(4)N](2)S/[(CH(3))(4)N](2)S(n), in an organic solvent (3-methoxypropionitrile) was employed in CdS quantum dot (QD)-sensitized solar cells (QDSSCs), and an unprecedented energy conversion efficiency of up to 3.2% was obtained under AM 1.5 G illumination. The QDs were linked to nanoporous TiO(2) via covalent bonds by using thioglycolic acid, and chemical bath deposition in an organic solvent was then used to prepare the QDSSCs, facilitating high wettability and superior penetration capability of the TiO(2) films. A very high fill factor of 0.89 was observed with the optimized QDSSCs.     

CuInS2量子点敏化太阳能电池中尺寸依赖的电子注入和光电性质

研究了CuInS₂（CIS）量子点敏化太阳能电池（QDSSCs）的电子注入和器件性能与粒子尺寸之间的依赖关系. 首先合成了不同尺寸的CuInS₂量子点（QDs）,制备了CuInS₂量子点敏化的TiO₂薄膜,并组装了量子点敏化太阳能电池. 通过循环伏安法确定了CuInS₂量子点的能级位置. 采用时间分辨荧光光谱分析测量了CuInS₂量子点到TiO₂薄膜的电子转移速率和效率. 结果发现,随着粒子尺寸从4.0 nm减小到2.5 nm,电子注入速率略微增加而电子注入效率减小,同时量子点敏化太阳能电池的开路电压基本不变,而光电转换效率、短路电流和填充因子（FF）均减小. 上述研究结果表明量子点敏化太阳能电池性能的优化可以通过改变量子点的尺寸来实现.     

CuInS_2量子点敏化太阳能电池中尺寸依赖的电子注入和光电性质

研究了CuInS2(CIS)量子点敏化太阳能电池(QDSSCs)的电子注入和器件性能与粒子尺寸之间的依赖关系.首先合成了不同尺寸的CuInS2量子点(QDs),制备了CuInS2量子点敏化的TiO2薄膜,并组装了量子点敏化太阳能电池.通过循环伏安法确定了CuInS2量子点的能级位置.采用时间分辨荧光光谱分析测量了CuInS2量子点到TiO2薄膜的电子转移速率和效率.结果发现,随着粒子尺寸从4.0 nm减小到2.5 nm,电子注入速率略微增加而电子注入效率减小,同时量子点敏化太阳能电池的开路电压基本不变,而光电转换效率、短路电流和填充因子(FF)均减小.上述研究结果表明量子点敏化太阳能电池性能的优化可以通过改变量子点的尺寸来实现.     

Quantum dot-sensitized solar cells incorporating nanomaterials

Quantum dot-sensitized solar cells (QDSSCs) are interesting energy devices because of their (i) impressive ability to harvest sunlight and generate multiple electron/hole pairs, (ii) ease of fabrication, and (iii) low cost. The power conversion efficiencies (η) of most QDSSCs (typically <4%) are, however, less than those (up to 12%) of dye-sensitized solar cells, mainly because of narrow absorption ranges and charge recombination occurring at the QD-electrolyte and TiO(2)-electrolyte interfaces. To further increase the values of η of QDSSCs, it will be necessary to develop new types of working electrodes, sensitizers, counter electrodes and electrolytes. This Feature Article describes the nanomaterials that have been used recently as electronic conductors, sensitizers and counter electrodes in QDSSCs. The nature, size, morphology and quantity of these nanomaterials all play important roles affecting the efficiencies of electron injection and light harvesting. We discuss the behavior of several important types of semiconductor nanomaterials (sensitizers, including CdS, Ag(2)S, CdSe, CdTe, CdHgTe, InAs and PbS) and nanomaterials (notably TiO(2), ZnO and carbon-based species) that have been developed to improve the electron transport efficiency of QDSSCs. We point out the preparation of new generations of nanomaterials for QDSSCs and the types of electrolytes, particularly iodide/triiodide electrolytes (I(-)/I(3)(-)), polysulfide electrolytes (S(2-)/S(x)(2-)), and cobalt redox couples ([Co(o-phen)(3)(2+)/(3+)]), that improve their lifetimes. With advances in nanotechnology, we foresee significant improvements in the efficiency (η > 6%) and durability (>3000 h) of QDSSCs.     

Sea urchin TiO2-nanoparticle hybrid composite photoelectrodes for CdS/CdSe/ZnS quantum-dot-sensitized solar cells

The sea urchin TiO(2) (SU TiO(2)) particles composed of radially aligned rutile TiO(2) nanowires are successfully synthesized through the simple solvothermal process. SU TiO(2) was incorporated into the TiO(2) nanoparticle (NP) network to construct the SU-NP composite film, and applied to the CdS/CdSe/ZnS quantum-dot-sensitized solar cells (QDSSCs). A conversion efficiency of 4.2% was achieved with a short-circuit photocurrent density of 18.2 mA cm(-2) and an open-circuit voltage of 531 mV, which corresponds to ～20% improvement as compared with the values obtained from the reference cell made of the NP film. We attribute this extraordinary result to the light scattering effect and efficient charge collection.     

Novel Quasi-solid-state Dye-sensitized Solar Cell Based on Monolayer Capped TiO2 Nanoparticles Framework Materials

Dodecylbenzenesulfonate (DBS)-capped TiO2 nanoparticles have been synthesized and employed in dye-sensitized solar cells to form a quasi-solid state electrolyte. Owing to the long alkyl-chain capping around the TiO2 nanoparticles interacting with the liquid solvent, the dye sensitized solar cell based on such DBS-capped TiO2 nanoparticle framework material gel electrolyte shows higher stability compared with the non-capped one in the long-term application and gives a comparable overall efficiency of 6.3% at AM 1.5 illumination.     

Easily manufactured TiO2 hollow fibers for quantum dot sensitized solar cells

TiO(2) hollow fibers with high surface area were manufactured by a simple synthesis method, using natural cellulose fibers as template. The effective light scattering properties of the hollow fibers, originating from their micron size, were observed by diffuse reflectance spectroscopy. In spite of the micrometric length of the TiO(2) hollow fibers, the walls were highly porous and high surface area (78.2 m(2) g(-1)) was obtained by the BET method. TiO(2) hollow fibers alone and mixed with other TiO(2) pastes were sensitized with CdSe quantum dots (QDs) by Successive Ionic Layer Adsorption and Reaction (SILAR) and integrated as a photoanode in quantum dot sensitized solar cells (QDSCs). High power conversion efficiency was obtained, 3.24% (V(oc) = 503 mV, J(sc) = 11.92 mA cm(-2), FF = 0.54), and a clear correspondence of the cell performance with the photoanode structure was observed. The unique properties of these fibers: high surface area, effective light scattering, hollow structure to facile electrolyte diffusion and the rather high efficiencies obtained here suggest that hollow fibers can be introduced as promising nanostructures to make highly efficient quantum dot sensitized solar cells.     

Environmentally Benign and Efficient Ag2S‐ZnO Nanowires as Photoanodes for Solar Cells: Comparison with CdS‐ZnO Nanowires

In this work, we develop a low‐temperature, facile solution reaction route for the fabrication of quantum‐dot‐sensitized solar cells (QDSSCs) containing Ag₂S‐ZnO nanowires (NWs), simultaneously ensuring low manufacturing costs and environmental safety. For comparison, a CdS‐ZnO NW photoanode was also prepared using the layer‐by‐layer growth method. Ultraviolet photoelectron spectroscopy analysis revealed type‐II band alignments for the band structures of both photoanodes which facilitate electron transfer/collection. Compared to CdS‐ZnO QDSSCs, Ag₂S‐ZnO QDSSCs exhibit a considerably higher short‐circuit current density (J_sc) and a strongly enhanced light‐harvesting efficiency, but lower open‐circuit voltages (V_oc), resulting in almost the same power‐conversion efficiency of 1.2 %. Through this work, we demonstrate Ag₂S as an efficient quantum‐dot‐sensitizing material that has the potential to replace Cd‐based sensitizers for eco‐friendly applications.     

染料敏化La~(3+)掺杂的TiO_2纳晶薄膜制备及其光电性能

采用溶胶-凝胶法制备出La3+掺杂的TiO2纳米粉体材料,通过料浆喷涂工艺制得掺杂La3+的TiO2薄膜并将其以N719染料敏化制成染料敏化太阳能电池(DSSC)。以X射线衍射(XRD)、扫描电镜(SEM)和DSSC测试系统对制得的La3+掺杂的TiO2纳米粉体材料、相应的La3+掺杂的TiO2薄膜以及制成的DSSC分别进行测试表征,研究了La3+掺杂对TiO2晶型和染料敏化太阳能电池性能的影响。XRD测试结果表明,La3+的掺杂改善了TiO2的颗粒分布;电池的测试结果说明,La3+掺杂量为0.5%,煅烧温度为450℃时制备的纳米TiO2膜DSSC电池性能最佳,光电转换效率达1.926%。     

Surface-treated TiO2 nanoparticles for dye-sensitized solar cells with remarkably enhanced performance

Dye-sensitized solar cells (DSSCs) were prepared by capitalizing on mesoporous P-25 TiO(2) nanoparticle film sensitized with N719 dyes. Subjecting TiO(2) nanoparticle films to TiCl(4) treatment, the device performance was improved. More importantly, O(2) plasma processing of TiO(2) film that was not previously TiCl(4)-treated resulted in a lower efficiency; by contrast, subsequent O(2) plasma exposure after TiCl(4) treatment markedly enhanced the power conversion efficiency, PCE, of DSSCs. Remarkably, with TiCl(4) and O(2) plasma treatments dye-sensitized TiO(2) nanoparticle solar cells produced with 21 μm thick TiO(2) film illuminated under 100 mW/cm(2) exhibited a PCE as high as 8.35%, twice of untreated cells of 3.86%.     

SnS-quantum dot solar cells using novel TiC counter electrode and organic redox couples

Low-cost quantum-dot sensitized solar cells (QDSSCs) were fabricated by using the earth-abundant element SnS quantum dot, novel TiC counter electrodes, and the organic disulfide/thiolate (T(2)/T(-)) redox couple, and reached an efficiency of 1.03?%. QDSSCs based on I(-)/I(3)(-), T(2)/T(-), and S(2-)/S(x)(2-) redox couples were assembled to study the role of the redox couples in the regeneration of sensitizers. Charge-extraction results reveal the reasons for the difference in J(SC) in three QDSSCs based on I(-)/I(3)(-), T(2)/T(-), and S(2-)/S(x)(2-) redox couples. The catalytic selectivity of TiC and Pt towards T(2)/T(-) and I(-)/I(3)(-) redox couples was investigated using Tafel polarization and electrochemical impedance analysis. These results indicated that Pt and TiC show a similar catalytic selectivity for I(-)/I(3)(-). However, TiC possesses better catalytic activity for T(2)/T(-) than for I(-)/I(3)(-). These results indicate the great potential of transition metal carbide materials and organic redox couples used in QDSSCs.     

Nanocrystalline TiO2 solar cells sensitized with InAs quantum dots

We report nanocrystalline TiO2 solar cells sensitized with InAs quantum dots. InAs quantum dots of different sizes were synthesized and incorporated in solar cell devices. Efficient charge transfer from InAs quantum dots to TiO2 particles was achieved without deliberate modification of the quantum dot capping layer. A power conversion efficiency of about 1.7% under 5 mW/cm2 was achieved; this is relatively high for a nanocrystalline metal oxide solar cell sensitized with presynthesized quantum dots, but this efficiency could only be achieved at low light intensity. At one sun, the efficiency decreased to 0.3%. The devices are stable for at least weeks under room light in air.     

CdSe/ZnS量子点敏化太阳能电池电子注入与光伏性能表征

合成了CdSe/ZnS核壳结构量子点(QDs), 将其作为光敏剂吸附在TiO2纳米晶薄膜上, 组装成量子点敏化太阳能电池(QDSSCs), 从电子注入速率和电池性能两方面对QDSSCs进行了表征. 为了定量研究ZnS层包覆对电子注入的影响, 运用飞秒瞬态光谱技术, 测试了包覆ZnS前后, CdSe-TiO₂体系的电子注入速率. 实验测得ZnS包覆前后电子注入速率分别为7.14×10¹¹s^-1和2.38×10^-11s^-1, 可以看出包覆后电子注入速率明显降低, 仅为包覆前的1/3. 电池器件J-V性能测试表明, ZnS作为绝缘层包覆在CdSe的表面有效提高了QDSSCs的填充因子和稳定性, 但同时也导致了效率的降低. 上述结果说明了电子注入速率的降低是导致电池电流和效率下降的重要原因, 为今后优化核壳结构QDSSCs的电流和效率提供了依据.     

三芳基咪唑富勒烯吡咯烷衍生物的合成及在CdSe量子点敏化太阳能电池中的应用

本文合成了两个结构新颖的三芳基咪唑类化合物5(Im)和6(Bn-Im),然后通过1,3-偶极化反应合成了C60吡咯烷衍生物7(Im-C60)和8(Bn-Im-C60),用MS, NMR, IR 等对其结构进行了表征。初次组装了七个太阳能电池,结构分别为FTO/TiO2/CdSe/Pt, FTO/TiO2/C60/Pt,FTO/TiO2/Im-C60/Pt,FTO/TiO2/ Bn-Im-C60/Pt, FTO/TiO2/C60-CdSe/Pt,FTO/TiO2/Im-C60-CdSe/Pt和FTO/TiO2/Bn-Im-C60-CdSe /Pt,对其光电性能进行了表征,结果表明：与CdSe敏化太阳能电池相比,以Im-C60-CdSe和Bn-Im-C60-CdSe为敏化剂的电池效率分别增加了5.28%和40.08%。     

Highly efficient,PbS:Hg quantum dot–sensitized,plasmonic solar cells with TiO2 triple-layer photoanode

Journal of Solid State Electrochemistry - Highly efficient, PbS:Hg quantum dot–sensitized, plasmonic solar cells with TiO2 triple-layer photoanode were fabricated by successive ionic layer...     

Development on Solid Polymer Electrolytes for Electrochemical Devices

Electrochemical devices, especially energy storage, have been around for many decades. Liquid electrolytes (LEs), which are known for their volatility and flammability, are mostly used in the fabrication of the devices. Dye-sensitized solar cells (DSSCs) and quantum dot sensitized solar cells (QDSSCs) are also using electrochemical reaction to operate. Following the demand for green and safer energy sources to replace fossil energy, this has raised the research interest in solid-state electrochemical devices. Solid polymer electrolytes (SPEs) are among the candidates to replace the LEs. Hence, understanding the mechanism of ions’ transport in SPEs is crucial to achieve similar, if not better, performance to that of LEs. In this paper, the development of SPE from basic construction to electrolyte optimization, which includes polymer blending and adding various types of additives, such as plasticizers and fillers, is discussed.     

染料敏化太阳能电池的二氧化钛膜性能研究

以二氧化钛(TiO₂)纳米粉(P25)为原料,把它研磨成胶状,用涂敷法制得TiO₂纳米多孔膜,并组装成太阳能电池,用100W氙灯作为模拟太阳光,对电池进行光电性能测试.根据电池的短路电流(I_sc)、开路电压(V_oc)和填充因子(ff)等指标来反映电池的性能.研究表明,分散剂乙酰丙酮、OP乳化剂、研磨时间和热处理后的保温时间长短对TiO₂膜的性能均有很大的影响.其结果是,乙酰丙酮0.15mL、OP乳化剂0.10mL、研磨时间1h和保温时间0.5h时,TiO₂膜的光电性能较好,I_sc、V_oc和ff分别为8.85mA、567mV和0.445.并用XRD和比表面及孔隙分析仪对TiO₂膜进行了表征.     

Composite Electrode SnO2／TiO2 for Dye-Sensitized Solar Cells

Composite nanoporous electrode SnO2/TiO2 was fabricated for the dye sensitized solar cell (DSSC) with N3 (Cis-Ru). After introducing of TiO2, the open-circuit photovoltage (Voc) was higher than that of the pure SnO2 electrode, while short-circuit photocurrent (Isc) was varied with the ratio of the TiO2. Appropriate content of the TiO2 can be beneficial to the efficiency of the solar cell, and it gives negative impact on the composite electrode when the content of TiO2 is higher.