ZnO纳米棒光阳极的制备及其天然染料敏化研究

采用溶胶-凝胶法和旋转涂覆法在FTO导电玻璃上制备ZnO种子层,以Zn(NO3)2和六亚甲基四胺(HMT)的混合溶液为生长液在ZnO种子层上制备出ZnO纳米棒薄膜,利用X射线衍射(XRD)、扫描电镜(SEM)对ZnO种子层及纳米棒薄膜的晶相及表面微观形貌进行了表征;研究了生长液浓度、生长时间对ZnO纳米棒薄膜生长的影响。实验表明,制备排列整齐的ZnO纳米棒阵列薄膜最佳条件为90℃环境下,基底竖直放置在0.025mol/L的生长液中,生长4h,纳米棒平均直径80nm左右。从新鲜草莓、桑葚中提取天然色素,对ZnO纳米棒电极进行敏化,组装成光电池;测试敏化电极的吸收光谱及光电池的伏安特性曲线。结果表明,桑葚色素在可见光区有更强的吸收特性,由桑葚色素敏化的电极组装的光电池,在模拟太阳光下,得到开路电压为228.75mV,短路电流为189μA,填充因子为0.37,光电转换效率为5.5×10-4。     

TiO_2光阳极染料敏化太阳能电池的研究进展

通过介绍染料敏化太阳能电池(dye-sensitized solar cells,简称DSSC)的研究背景,指出了DSSC的研究意义。从光阳极、染料敏化剂、电解质和对电极等基本构成要素方面综述了DSSC的研究现状,并展望了其未来的发展方向。     

29种天然染料敏化的太阳电池的性能研究

采用超声波萃取法从29种天然植物中提取染料, 测试天然染料的紫外-可见光(UV-vis)吸收光谱,探讨天然染料所 含的色素种类。采用水热法制备了TiO₂薄膜电极,用所提取的29种天然染料敏化TiO₂光 电极并将其组装成染料敏化太阳电池(DSSCs)。测试天然染料敏化的DSSCs 的光电性能结果显示,天然染料敏化的DSSCs的开路 电压Voc为0.46~0.64 V,短路电流I_sc为0.07~3.61mA· cm－2,其中山竹皮敏 化的DSSCs光电性能最佳,对应的I_sc和光电转换 效率η分 别为3.61mA·cm－2和2.13%。从天然 染料中挑选出7种不同吸收波段色素的染料进行协同敏化,UV-vis吸收光谱测试结 果显示混合染料的吸收峰一般有微小偏移。光电性能测试结果表明,协同敏化后的DSSCs的 性能一般都介于天然染料单独敏 化的两个DSSCs的性能之间,其中山竹皮和芥蓝协同敏化的DSSCs的η最高,为1.70%。对实验结果进行深入分析,探讨提高天然染料 敏化的DSSCs光电性能的途径。     

酰化黑枸杞染料光谱分析及其光电性能的研究

目前染料敏化太阳能电池的天然染料主要以花青 素为主,但花青素敏化太阳能电池的 光电转换效率比较低。本研究从黑枸杞中提取花青素,利用阿魏酸、草酸和咖啡酸对黑枸杞 染料进行酰化改性,并将其作为敏化剂组装染料敏化太阳能电池。利用紫外-可见吸收光谱 , 循环伏安测试对染料的光谱吸收特性及光电性能进行了表征。结果表明:黑枸杞经酰化后光 谱范围有效扩宽,酰化黑枸杞染料均能将电子注入到TiO₂导带边缘,并且咖啡酸酰化后的 光吸收效率最大。在100 mW/cm²入射光照下,黑枸杞经酰化后光电 转换效率提高,其中咖 啡酸酰化后光电转换效率最大为1.01%。采用电化学阻抗进一步分析 电子在电池界面的传 输,酰化黑枸杞染料能够有效的抑制TiO₂与离子电解液之间的复合率。     

染料共敏化纳米晶太阳能电池的性能研究

采用罗丹明-B与香豆素混合的方法,配制成敏化剂修饰纳米晶薄膜.实验结果证明,这种共敏化的方法可以在可见光范围内有效提高电池的吸光度,使得电池的性能比单独使用罗丹明-B敏化有了大幅度提高.实验中,罗丹明-B与香豆素共敏化的电池的开路电压达到了550mV,短路电流达到了0.1375mA/cm^2.     

叶绿素与4种天然染料共敏化太阳电池的光电化学性能研究

利用紫外-可见吸收光谱 对提取的叶绿素和4种天然染料(茶多酚、靛蓝、 红花黄、栀子黄)以及叶绿素与4种染料的共敏化 进行比较。通过电化学方法,研 究单一染料和共敏化染料的氧化还原电位。结果表明,杨树叶子中叶绿素最佳的提取 工艺条件为:提取料液比1∶50,提取温度60 ℃,提取时间3.5h。叶绿素与4种天然染料共敏化后不仅拓宽光谱吸 收波长范围,而且染 料激发态氧化电位与TiO₂导带能级相匹配。其中叶绿素与栀子黄染料共敏化后,光电化学 性能最好。在太阳光模拟下,叶绿素与栀子黄对电池进行共敏化后光电转换 效率提高到0.67%,是叶绿素染料单独敏化的2.91倍。     

基于硫化镍的染料敏化太阳能电池光伏性能研究

在典型的染料敏化太阳能电池中，基于铂金属的对电极用于收集外电路的电子，并催化氧化态电解质还原。然而，由于铂金属为贵金属，因此需要开发廉价材料的对电极，从而降低生产成本。低温沉积法是一种简单的制备方法，它的主要优点是，在不需要高温加热的条件下，可以直接在导电衬底上沉积，制备出拥有优异催化性能的硫化镍薄膜，然后直接用作染料敏化太阳能电池的对电极。结果显示，基于硫化镍薄膜对电极的染料敏化太阳能电池的最佳光电转换效率为6.12%，这与基于铂对电极的染料敏化太阳能电池的转换效率(6.16%)非常接近。上述实验结果表明低温沉积法制备的硫化镍薄膜具有优异的电催化性能，有利于染料敏化太阳能电池的光伏性能提升。     

TiO2薄膜染料敏化太阳电池的性能北大核心

采用旋涂法、提拉法、水热法、涂覆法制备了TiO2薄膜,利用紫葡萄皮染料分子敏化了TiO2薄膜电极,制备出太阳电池。测试结果表明涂覆法制备的太阳电池的效率最好,初始短路电流密度、开路电压分别为2.840 m A/cm2和0.594 m V,而稳定性最差。相同条件下,其电池短路电流密度、开路电压与初始短路电流密度、开路电压的偏差百分比分别为13.3%和10%。旋涂法、提拉法、水热法制备的电池初始短路电流密度分别为0.619,1.071和0.901 m A/cm2,初始开路电压分别为0.447,0.481和0.488 m V,稳定性基本一样,短路电流密度与初始短路电流密度的偏差百分比分别为9.3%,9.8%和9.3%,开路电压与初始开路电压的偏差百分比分别为8.2%,7.3%和6.9%。电池的不稳定性在初期很强,衰退很快,后期趋于缓和。     

新型色素增感型太阳能电池提高发电效率

日本产业技术综合研究所(AIST)新开发出一种高性能色素增感型太阳能电池,其发电效率高,耐久性好,而且生产成本低.     

红外控温材料丙烯酸接枝石蜡的酰化研究

以丙烯酸(AA)极性单体与石蜡接枝得到的丙烯酸接枝石蜡与酰胺反应生成酰化的接枝石蜡.用红外光谱仪和差示扫描量热仪对酰化的丙烯酸接枝石蜡的结构和热性能进行了分析.与未改性石蜡相比,酰化的丙烯酸接枝石蜡相变温度提高了16.3％,相变潜热提高了59.07％,在三种改性石蜡中酰化的丙烯酸接枝石蜡相变温度最高,相变潜热最大.分析三种改性石蜡的分子结构与其相变温度相变潜热的关系.     

Significant improvement of phenothiazine organic dye-sensitized solar cell performance using dithiafulvenyl unit as additional donor

The simple D-π-A phenothiazine organic dye (C₆PTZ) was modified by introducing excellent electron donor dithiafulvenyl unit with alkyl chains as additional donor to form novel D-D-π-A organic dyes WD14 and WD15 for the first time. These organic dyes were successfully applied in dye-sensitized solar cells and the photovoltaic properties were investigated. Compared with the reference dye C₆PTZ, the power conversion efficiencies increased significantly from 4.16% to 5.87% (WD14) and 6.63% (WD15). The performance improvement is due to the following advantages of the introduction of dithiafulvenyl unit with alkyl chains. Firstly, the light-harvesting capability is improved by increasing electron-donating ability. Secondly, it leads to more efficient inhibition of aggregation between dye molecules. Thirdly, the charge recombination between photoelectrons injected into the conduction band of TiO₂ and the oxidized form $\left({{\text{I}}_3}^{-}\right)$ of the redox couple is restricted due to the double blocking effect originating from the long hexyl chains of the dithiafulvenyl unit and hexyl side chain attached to phenothiazine unit. This work indicates that the incorporation of dithiafulvenyl unit into the simple phenothiazine organic dye greatly improves the solar cell performance, and it will be an effective approach to develop high-performance metal-free organic dyes.     

An oligothiophene dye with triphenylamine as side chains for efficient dye-sensitized solar cells

A novel oligothiophene-cyanoacrylic acid photosensitizer with two triphenylamine side chains (7T-2TPA) is designed and synthesized for dye-sensitized solar cells. 7T-2TPA exhibits broad (250-600 nm) and strong absorption (ε = 5.0 × 10⁴ L mol⁻¹ cm⁻¹ at 496 nm). The optical band gap (E_g) is estimated from the onset absorption edge to be 2.07 eV. The oxidation potential E_ox and reduction potential E_red vs NHE of the dye is 0.93 and −1.14 V, respectively. Dye-sensitized solar cell (DSSC) based on 7T-2TPA exhibits an open-circuit voltage (V_oc) of 724 mV, a short-circuit current density (J_sc) of 16.28 mA cm⁻², a fill factor (FF) of 0.684 and a power conversion efficiency of 8.06%. The efficiency of 8.06% is similar to that for widely used N719-based cell fabricated and measured under the same conditions.     

Effect of imidazole derivatives in triphenylamine-based organic dyes for dye-sensitized solar cells

In order to study the influence of imidazole derivatives in triphenylamine-based organic dyes, two different imidazole derivatives are introduced into the phenyl ring of the triphenylamine core, coded as TPA-B5 and TPA-B6, respectively. The photophysical and electrochemical properties of the dyes are investigated by UV–vis spectroscopy and cyclic voltammetry. TPA-B5 increases the molar extinction coefficients and λ_max because of the extension of the π-conjugation structure of the dye and non-planar structure of imidazole derivative. However, TPA-B6 does not increase the molar extinction coefficients and λ_max compared with a simple triphenylamine derived dye (TPA-1), which may be due to the planar structure of imidazole derivative and benzene ring. The structure of TPA-B6 is in favor of the formation of dye aggregates on the semiconductor surface and the recombination of conduction band electrons with triiodide in the electrolyte. Overall conversion efficiencies of 3.13% and 1.21% under full sunlight (AM 1.5G, 100 mW cm^?2) irradiation are obtained for DSSCs based on the two new dyes, under the same conditions, the dye TPA-1 and di-tetrabutylammonium cis-bis(isothiocyanato) bis(2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium(II) (N719) give overall conversion efficiencies of 2.23% and 5.38%, respectively. Although the overall conversion efficiencies of these dyes are not very high, the results will still afford significant value for future development of efficient D–π–A sensitizers.     

Synthesis and photovoltaic property of pyrrole-based conjugated oligomer as organic dye for dye-sensitized solar cells

A new pyrrole-based conjugated oligomer (P1) was obtained with phenyl-linked triphenylamine moieties as an isolation group. Little aggregations were observed whether oligomer P1 was absorbed on titanium dioxide (TiO2) surface or in solid state. Since the pyrrole-based moieties in donor-π-acceptor type was the core component ofoligomer P1 for light absorption, the corresponding dyesensitized solar cell (DSSC) demonstrated the efficiency of light-to-electrical conversion by 0.48%. Higher conversion efficiency could be achieved by tuning the size of the isolation groups and the structure of the donor-π-acceptor type dyes.     

Novel organic dyes containing N-bridged oligothiophene coplanar cores for dye-sensitized solar cells

Three novel organic dyes adopting fully-fused coplanar heteroarene as the donor moieties end-capped with two cyanoacrylic acids as acceptors and anchoring groups have been synthesized, characterized, and used as the sensitizers for dye-sensitized solar cells (DSSCs). The photophysical and electrochemical properties of the novel dyes and the characteristics of the DSSCs based on the novel organic dyes were investigated. The incorporation of the coplanar cores with electron-donating N-bridges are beneficial for the better intramolecular charge transfer (ICT), giving these new dyes good light-harvesting capability. The LUMO energy levels of these coplanar heteroacene-based dyes are sufficiently high for the efficient electron injection to TiO₂ upon photo-excitation, while the suitable HOMOs allow the regeneration of oxidized dyes with the electrolyte redox (I⁻/I₃⁻). The structural features of the coplanar cores (penta vs. hexa heteroarene) as well as the alkyl substitutions play crucial roles in governing the physical properties and device performance. Among these three novel organic sensitizers, the EHTt dye composed of a fully fused hexa-arene core and less bulky N-alkyl groups caused the DSSC to show the best photovoltaic performance with an open-circuit voltage (V_OC) of 0.58 V, a short-circuit photocurrent density (J_SC) of 13.72 mA/cm², and a fill factor (FF) of 0.69, yielding an overall power conversion efficiency (PCE) of 5.52% under AM 1.5G solar irradiation.     

Effect of deoxycholic acid on performance of dye-sensitized solar cell based on black dye

The effect of coadsorption with deoxycholic acid (DCA) on the performance of dye-sensitized solar cell (DSSC) based on [(C4H9)4N]3[Ru(Htcterpy)(NCS)3](tcterpy= 4,4′,4"-tricarboxy-2,2′:6′,2"-terpyridine), a socalled black dye, had been investigated. Results showed that the coadsorption of DCA with the black dye results in significant improvement in the photocurrent and mild increase in the photovoltage, which leads to an enhancement of overall power conversion efficiency by 9%. The enhancement of photocurrent was attributed to the increased efficiency of charge collection and/or electron injection. The coadsorption with DCA suppressed charge recombination and thus improved open-circuit photovoltage.     

天然染料作为Zn2TiO4太阳能电池敏化剂的研究

从植物的叶、花、果实和果皮中提取出7种天然染料,通过对它们的UV-vis吸收光谱比较发现,从月季叶中提取的染料表现出较好的光响应性.采用溶胶-凝胶法制备了纳米晶Zn2TiO4薄膜电极,并利用X射线衍射(XRD)、扫描电镜(SEM)对其晶相及表面形貌进行了表征;制备了月季叶染料敏化Zn2TiO4电极,并以此为光阳极组装了...     

Investigation of benzo(1,2-b:4,5-b′)dithiophene as a spacer in organic dyes for high efficient dye-sensitized solar cell

Two benzo(1,2-b:4,5-b′)dithiophene (denoted as BDT) based organic dyes, Dye 1 and Dye 2, containing triphenylamine and carbazole in the molecular frameworks respectively, were synthesized, characterized and applied in dye-sensitized solar cells (DSSCs). The photo-physical, photovoltaic, and electrochemical properties of the two dyes were analyzed in this work. The two dyes exhibit strong charge transfer absorption bands in the visible region. The dyes were applied in dye sensitized solar cells obtaining 11.34 mA/cm², 0.75 V and 0.74, for the short-circuit photocurrent density (J_sc), open-circuit voltage (V_oc), and fill factor (FF) respectively, corresponding to an overall power conversion efficiency of 6.3%. These results revealed that BDT-based dyes are promising dyes for DSSCs.     

Low glass transition temperature hole transport material in enhanced-performance solid-state dye-sensitized solar cell

A new triarylamine-based hole transport materials (HTM) with branched side chain giving low glass transition temperature (T_g) is synthesized and incorporated into a solid state dye sensitized solar cell. This designing of molecular structure of HTM for lowering the T_g along with viscosity and surface tension of the casting solution effectively increases the pore-filling fraction (PFF) as the cell is heated during the fabrication, leading to an 8 fold increasing in cell efficiency over cells without heat treatment. We relate the cell performance improvement not only due to the PFF of TiO₂ by the (HTM), but also because of morphological and thickness changes in the hole transport material (HTM) capping layer.     

Electrochemical analysis of dye adsorption on aligned carbon nanofiber arrays coated with TiO2 nanoneedles for dye-sensitized solar cell

An electrochemical method has been developed to analyze dye absorption on the aligned carbon nanofiber arrays coated with TiO2 nanoneedles for dyesensitized solar cell. The unique nanostructure with the roughness factor of 90.6 provides a large effective surface area for dye adsorption. The experimental results showed that the dye molecules cover 39.7% of the TiO2 surface area which influences the performance of dye-sensitized solar cell. The electrochemical method provides the information of the coverage of dye molecules which is a key issue to optimize solar cell performance.