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。     

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。     

TiO2基染料敏化太阳能电池的表面修饰及性能研究

采用水热法制备TiO₂浆料,用La(NO₃)₃溶 液浸泡TiO₂薄膜获得修饰电极。用X射线光电子能谱(XPS) 和扫描电子显微镜(SEM)对修饰电极的主要成分及形貌进行表征的结果显示,电极薄膜分为 上下两层,表 面包覆层粒径较大,为La₂O₃颗粒;下层颗粒粒径较小,为TiO₂颗粒。电流-电压测 试结果显示,与修饰 前相比,用La(NO₃)₃溶液浸泡30min获得的膜电极性能最优,使 开路电压和短路电流分别提高了6.8%和 18.5%。电化学阻抗谱(EIS)测试结果表明,相同偏压下,TiO₂/La ₂O₃电极界面复合电阻比TiO₂要大,说明 La₂O₃包覆层在一定程度上抑制了界面的电子复合,改善了电池的光电化学性能。     

染料敏化太阳电池染料协同敏化及其吸附机理

提取了菠菜、藏红花、金银花、雪菊、山楂5种光谱吸收区间不同的植物染料,根据光谱吸收互补性的原则以不同类型、不同比例进行了混合,用于染料敏化太阳电池(DSSC)光阳极的协同敏化,测定了各种染料、染料与TiO_2吸附后的UV-vis吸收光谱及不同染料敏化后的DSSC光电性能。实验结果表明:光谱吸收区间不同的染料混合后能有效拓宽光谱吸收范围和峰值吸光度,5种染料以相应比例协同敏化后的电池性能最佳,与单一染料敏化性能中最好的菠菜敏化电池相比,开路电压提升0.023 V,短路电流提升0.342 mA·cm~(-2),光电转换效率提升0.94%(相比提升2.68倍)。最后从染料的有效色素类型与TiO_2薄膜之间的吸附机理入手解释了造成几种染料电池光电性能差异的原因,从而提出了混合染料协同敏化DSSC应遵循的几项基本原则。     

TiO_2纳米管阵列对染料敏化太阳能电池性能的影响

通过恒压阳极氧化法在Ti箔表面制备了结构规整的TiO2纳米管阵列,研究了氧化时间和退火温度对纳米管阵列的尺寸和晶体结构的影响。用制得的纳米管阵列电极组装了染料敏化太阳能电池(DSSC),研究了纳米管长度、退火温度和电极面积对DSSC光电性能的影响。结果表明,纳米管管径和壁厚均与氧化时间无关,而纳米管长度则随着氧化时间延长而增加。在450℃及更低温度退火时,纳米管中只出现锐钛矿相;而在500℃退火时,纳米管中则又出现了金红石相。由厚度为27μm、退火温度为450℃的纳米管阵列电极组装成的DSCC具有最佳的光电转化性能。DSCC的光电转化效率随电极面积的增加而降低。     

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。     

一种柔性染料敏化太阳能电池的初步研究

染料敏化太阳能电池(DSSC)与商用硅电池相比,由于具有转化效率较高、制作成本低等一系列优点,近年来已受到人们的广泛关注.简要介绍了DSSC太阳能电池的结构和基本原理,重点分析了DSSC太阳能电池的关键组成和影响光电转化效率的因素.采用胶带涂覆法在柔性ITO衬底上制备了多孔纳米TiO2薄膜,通过给其配置相应的染料和电解...     

染料敏化TiO_2单晶纳米棒阵列太阳电池的性能

采用水热法一步合成出TiO2单晶纳米棒有序阵列,进而制备出染料敏化太阳电池。重点探讨了退火时间变化对电池光电转化效率的影响。研究结果表明,与未退火的纳米棒组装而成的电池相比,退火后的纳米棒电池显示出更高的光电转化效率。并且当退火时间为7 min时,光电转化效率最高(5.05%),提高到未退火电池光电转化效率的300%以上。电池性能提高的原因有:TiO2纳米棒阵列与衬底间结合力的增强有利于电子传输;表面态缺陷的减少有利于抑制光生载流子的复合。结合SEM,TEM和J-V曲线等表征手段探讨了这一现象背后的物理机制。     

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...     

用于染料敏化太阳电池的新型碳纳米管材料

介绍了利用简单有效的电泳沉积工艺制备新型碳纳米管薄膜材料,并应用于染料敏化太阳电池。通过场发射扫描电子显微镜(FESEM)和透射电子显微镜(TEM)等表征手段发现,制备的新型碳纳米管薄膜材料直径均匀分布,且形成一种均匀的网状结构,这种均匀的网状结构有利于电子的传输。循环伏安法测试其电化学性能,并且对制备的染料敏化太阳电池的光电性能进行测试。实验结果表明,电泳沉积制备的碳纳米管薄膜具有良好的导电和催化性能,作为对电极组装的染料敏化太阳电池光电转换效率达到6.54%,有希望替代传统的铂对电极。     

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.     

Highly efficient dye‐sensitized solar cells using phenothiazine derivative organic dyes

Two novel organic dyes have been synthesized using electron rich phenothiazine as electron donors and oligothiophene vinylene as conjugation spacers. The two dyes (2E)‐2‐cyano‐3‐(5‐(5‐((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐7‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)acrylic acid (PTZ‐1) and (2E)‐3‐(5‐(5‐(4,5‐bis((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐3‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)thiophen‐2‐yl)‐2‐cyanoacrylic acid (PTZ‐2) were fully characterized and employed in dye‐sensitized solar cells (DSCs) to explore the effect of disubstituted donors on photovoltaic (PV) performance. The solar cells sensitized by the PTZ1 dye have a high IPCE plateau of 80% and achieve a short‐circuit photocurrent density of 12.98 mA/cm², an open‐circuit voltage of 0.713 V, and a fill factor (ff) of 66.6%, corresponding to a conversion efficiency of 6.17% under AM 1.5 100 mW/cm² illumination. The different performance of the solar cells based on the two dyes can be understood from the studies of the electron kinetics by electrochemical impedance spectroscopy (EIS). These investigations reveal that disubstituted donors in the organic sensitizers of three or more conjugation units deteriorate the PV performance due to enhanced recombination. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of using multi‐component electrolytes on the stability and properties of solar cells sensitized with simple organic dyes

In this paper we present experimental results for electrochemical (dye‐sensitized) solar cells that were prepared in our laboratory in order to examine some of the major factors affecting the efficiency and the stability of such cells. Nanostructured TiO₂ thin films were prepared and sensitized using an organic dye. For the purpose of this study three different types of electrolytes were developed: a standard‐type electrolyte containing potassium iodide and iodine in propylene carbonate (PC) and two novel, multi‐component electrolytes containing potassium iodide and iodine dissolved in varying mixtures of PC and EG (ethylene glycol). It was demonstrated that the combined properties of the two solvents in the multi‐component electrolytes enhance the efficiency and improve considerably the stability of the cells. Copyright © 2010 John Wiley & Sons, Ltd.     

Uses of new natural dye photosensitizers in fabrication of high potential dye-sensitized solar cells (DSSCs)

In the present study, dye-sensitized solar cells (DSSCs) were fabricated by sensitizing TiO₂ P25-based electrodes using a series of natural dye extracted from plant sources of Reseda luteola, Berberis integerrima, Panica granatum Pleniflora, Consolida orientalis, Reseda gredensis, Clemetis orientalis, Adonis flammea, Salvia sclarea, and Consolida ajacis. The optical properties of the natural dye extracts were investigated by UV–vis spectroscopy. The crystalline structure and morphological characteristic of TiO₂ electrode were analyzed by XRD and SEM, respectively. Our findings showed that due to Delphinidin is the main pigment of C. ajacis and interaction between the hydroxyl groups of the Delphinidin and the TiO₂ surface is very efficient, this sensitizer owns the best photovoltaic performance among the all natural dyes. Photoelectrochemical performance of the natural dyes based-DSSCs illustrated short-circuit photocurrent (Jsc) and open-circuit voltages (Voc) ranging from 0.004 to 0.68 mA and 0.37 to 0.64, respectively.     

Enhancement of dye sensitized solar cell efficiency via incorporation of upconverting phosphor nanoparticles as spectral converters

Upconverting NaYF₄:Yb³⁺,Er³⁺/NaYF₄ core‐shell (CS) nanoparticles (NPs) were synthesized by thermal decomposition of lanthanide trifluoroacetate precursors and mixed with TiO₂ NPs to fabricate dye‐sensitized solar cells (DSSCs). The CS geometry effectively prevents the capture of electrons because of the surface states and improves photo‐emission. The as‐synthesized CS NPs show upconversion (UC) luminescence, converting near infrared (NIR) light into visible light (450–700 nm), making the photon absorption by the ruthenium‐based dyes (which have little or no absorption in the NIR region) possible. The champion DSSCs fabricated using CS UC NPs (average size = 25 nm) show enhancements of ~12.5% (sensitized with black/N749 dye) and of ~5.5% (sensitized with N719 dye) in overall power conversion efficiency under AM 1.5G illumination. This variation in the enhancement of the DSSC efficiencies for black and N719 dyes is attributed to the difference in the extinction coefficient and the absorption wavelength range of dyes. Incident photon‐to‐current conversion efficiency measurements also evidently showed the photocurrent enhancement in the NIR region of the spectrum because of the UC effect. The results prove that the augmentation in efficiency is primarily due to NIR to visible spectrum modification by the fluorescent UC NPs. Copyright © 2015 John Wiley & Sons, Ltd.     

Enhanced photovoltaic performance of cross‐linked ruthenium dye with functional cross‐linkers for dye‐sensitized solar cell

Photovoltaic performance of cross‐linkable Ru(2,2′‐bipyridine‐4,4′‐bicarboxylic acid)(4,4′‐bis((4‐vinyl benzyloxy)methyl)‐2,2′‐bipyridine)(NCS)₂ (denoted as RuS dye) adsorbing on TiO₂ mesoporous film was enhanced by polymerizing with either ionic liquid monomer, 1‐(2‐acryloyloxy‐ethyl)‐3‐methyl‐imidazol‐1‐ium iodide (AMImI), to form RuS‐cross‐AMImI or di‐functional acrylic monomer with ether linkage, triethyleneglycodimethacrylate (TGDMA), to form RuS‐cross‐TGDMA. Their cross‐linking properties were investigated by UV–vis spectroscopy by rinsing with 0.1 N NaOH aqueous solution. The power conversion efficiencies (PCEs) of dye‐sensitized solar cells (DSSCs) with RuS‐cross‐AMImI and RuS‐cross‐TGDMA both reached over 8% under standard global air mass 1.5 full sunlight. The increased PCE for DSSCs with RuS‐cross‐AMImI comparing with cross‐linked RuS was attributed to the I⁻ counterion of AMImI increasing the charge regeneration rate of RuS dye, whereas that with RuS‐cross‐TGDMA was attributed to the Li⁺ coordination property of TGDMA. The photovoltaic performance of RuS‐cross‐TGDMA was also slightly better than that of RuS‐cross‐AMImI because of higher open‐circuit photovoltage (V_oc) and short‐circuit photocurrent (J_sc). Its higher V_oc was supported by the Bode plot of impedance under illumination and Nyquist plots at dark, whereas higher J_sc was supported by the incident monochromatic photon‐to‐current conversion efficiency spectra and charge extraction experiments. Copyright © 2013 John Wiley & Sons, Ltd.