苯基磷酸联吡啶钌络合物敏化纳晶多孔TiO2薄膜电极光电性能研究

用有机光敏染料敏化半导体,通过染料分子的吸附功能基团与半导体相互作用,使染料分子与半导体表面之间建立电性耦合,进行有效的电荷转移,可以形成有机-半导体复合新型光电功能材料。联吡啶钌络合物有较强的可见光吸收、氧化还原性能可逆、氧化态稳定性高,是一类性能优越的有机光敏染料。近来许多研究发现,羧酸联吡啶钌的强吸附与TiO₂纳晶薄膜的大比表面相结合,导致光生电荷快速注入TiO₂导带达到有效的电荷分离,得到了接近100%的单色光光电流效率^[1]。为研究联吡啶钌分子的不同吸附功能基团与TiO₂纳晶薄膜表面的相互作用对提高光电性能的影响,本文报道苯基磷酸取代的联吡啶钌络合物敏化纳晶多孔TiO₂薄膜的光电性能。     

N3敏化Ho3+离子修饰TiO2纳米晶电极的光电化学性质

研究了Ho3+离子表面修饰对TiO2纳米晶电极光电性能的影响. TiO2表面氧化钬的存在一方面降低了染料和TiO2之间的电子注入速率, 而另一方面它也能够抑制电荷复合. 结果表明, 在TiO2纳米晶薄膜表面修饰一定厚度的Ho3+离子层, 在电极表面就形成了一个势垒, 能够有效抑制电极表面的电荷复合, 从而提高了染料敏化太阳能电池的光电压和光电转化效率. 在93.1 mW·cm-2白光照射下, TiO2/Ho-0.1 和TiO2/Ho-0.2(0.1 和0.2分别是修饰TiO2电极的Ho3+溶液的浓度, 单位是mol·L-1)两个电极的光电转化效率分别达到8.3%和7.6%, 与TiO2电极(7.2%)比较, 分别增大了15%和5%.     

N3敏化Ho~（3＋）离子修饰TiO2纳米晶电极的光电化学性质

研究了Ho3+离子表面修饰对TiO2纳米晶电极光电性能的影响.TiO2表面氧化钬的存在一方而降低了染料和TiO2之间的电子注入速率,而另一方面它也能够抑制电荷复合.结果表明,在TiO2纳米晶薄膜表面修饰一定厚度的HO3+离子层,在电极表面就形成了一个势垒,能够有效抑制电极表面的电荷复合,从而提高了染料敏化太阳能电池的光电压和光电转化效率.在93.1 mW·cm-2白光照射下,TiO2/Ho-0.1和TiO2/Ho-0.2(0.1和0.2分别是修饰TjO2电极的Ho3+液的浓度,单位是mol·L-1)两个电极的光电转化效率分别达到8.3%和7.6%,与TiO2电极(7.2%)比较,分别增大了15%和5%.     

纳米结构TiO2/聚3-己基噻吩多孔膜电极光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了ITO/聚3-己基噻吩(ITO/ P3HT)膜和纳米结构TiO2/聚3-己基噻吩(TiO2/P3HT)复合膜的光电转换性质. 结果表明, P3HT膜的禁带宽度为1.89 eV, 价带位置为－5.4 eV. 在ITO/TiO2/ P3HT复合膜电极中存在p-n异质结, 在一定条件下异质结的存在有利于光生电子-空穴对的分离. P3HT修饰ITO/TiO2电极可使光电流发生明显的红移, 从而提高了宽禁带半导体的光电转换效率.     

柔性TiO2纳米管薄膜电极的制备及其光电性能

采用水热合成法制备出TiO₂纳米管,通过XRD、TEM和氮气等温吸附-脱附仪等测试手段对TiO₂纳米管进行了表征.用烧结的TiO₂纳米管和P25粉末混合制成薄膜电极,并研究了薄膜电极的表面形貌、染料吸附量和光电性能.研究表明,加入TiO₂纳米管可以制备出机械稳定的薄膜;掺杂TiO₂纳米管的含量越多,薄膜电极的染料吸附量越大;掺杂5%烧结纳米管粉末的薄膜电极的光电性能最好,其短路电流可达3.25mA,光电转换效率达到1.67%.     

卟啉衍生物敏化纳米TiO2多孔膜电极的光电性质研究

采用中位-四[邻-(3-磺酸基丙氨基)苯基]卟啉(TArP1)和中位-四[对-(3-磺酸基丙氨基)苯基]卟啉(TArP2)分别对纳米TiO2多孔膜电极进行敏化。对两种敏化电极进行了UV-V is光谱测试,结果表明,TiO2与TArP2的作用比与TArP1的作用强。在相同浸泡条件下,TiO2电极吸附TArP2的量大于吸附TArP1的量。将两种敏化电极分别组装成光电化学电池,从光电化学电池的I-V曲线计算TArP2敏化的光电化学电池的总光电转换效率(η)为0.15%,而TArP1敏化的光电化学电池的η为0.09%。     

基于TiO2纳米管阵列的高效正面透光型染料敏化太阳能电池的制备及其光电性能

报道了一种基于TiO2纳米管(TNT)阵列正面透光型光阳极的高效染料敏化太阳能电池.将TNTs在450°C烧结后能避免其有序结构在HF处理过程中被破坏,使膜内高速电子传输通道被保留,有利于染料敏化太阳能电池(DSSC)实现高速电荷传输.再用HF、TiCl4、HF和TiCl4混合等溶剂对TNTs进行处理,提高其表面粗糙度以吸附更多染料.染料吸附量的增加能提高光阳极在300-570 nm波段光子捕获效率,该波段是染料吸收光子的主要区域.然而,在染料吸收光子较弱的长波段区域(570-800 nm)光子捕获效率的增加主要源于光阳极光散射率的提高.光阳极光子捕获效率的提高使DSSC的内外量子效率在全波段(300-800 nm)均有所增加,从而使短路电流明显提高.从电化学阻抗数据可知,与电子传输性能密切相关的电化学参数如电荷传输电阻、界面电荷复合电阻、电容、电子寿命、电子扩散长度和电子收集效率等在含处理过的TNTs光阳极DSSC中均有所改善,从而提高电池光电转换效率.含HF和TiCl4混合溶剂处理TNTs光阳极的DSSC最高光电转换效率能达到7.30%,比未处理的DSSC(5.38%)提高35.69%.     

染料敏化纳米晶体TiO2太阳能电池的对电极结构

通过对染料敏化纳米晶体TiO₂太阳能电池的对电极的结构进行改进,设计了一种可大容量储存电解质和补充电解质的新型对电极结构.当染料敏化纳米晶体TiO₂太阳能电池因液态电解质挥发泄漏而失效时,可以对其进行液态电解质的及时补充,从而使失效的染料敏化纳米晶体TiO₂太阳能电池重新恢复工作.该新型对电极结构为解决染料敏化纳米晶体TiO₂太阳能电池由于液态电解质泄漏导致的寿命降低问题提供了一种新的解决方法.     

染料敏化TiO2纳米晶多孔膜电极的带边移动

染料敏化ＴｉＯ２纳米晶多孔膜电极的带边移动郝彦忠李卫华何君勇杨迈之＊蔡生民（北京大学化学与分子工程学院１００８７１）郝彦忠男，３０岁，讲师，研究领域：光电化学太阳能转换＊联系人国家自然科学基金资助项目１９９８－０３－１６收稿，１９９８－０５－１４修回...     

La3+-SiO2掺杂纳米TiO2的合成及其光催化降解甲基橙的研究

以三嵌段非离子表面活性剂P123为模板,采用水热法合成了La3+-SiO2掺杂纳米TiO2,通过X射线衍射(XRD)、红外光谱(FT-IR)、紫外-可见漫反射吸收光谱(DRS)等手段,考察了La3+-SiO2掺杂纳米TiO2的结构与光学特性.实验结果表明,La3+和SiO2掺杂使TiO2的晶粒在生长过程中受到阻碍.Ti-O-Si键和Ti-O-La键的形成抑制了金红石相的形成和晶粒长大,提高了TiO2的热稳定性,有利于获得高纯度锐钛矿相纳米TiO2.La3+-SiO2掺杂将TiO2的光响应范围拓宽至可见光区,提高了纳米TiO2的光催化性能.与纯纳米TiO2相比,La3+-SiO2掺杂纳米TiO2光催化降解甲基橙的性能显著提高.     

Adsorption of 4‐tert‐Butylpyridine on TiO2 Surface in Dye‐Sensitized Solar Cells

4‐tert‐Butylpyridine (4‐TBP) has been widely used as additive in dye‐sensitized solar cells (DSC), owing to its improvement of the fill factor and the open circuit voltage of DSC. In this paper, the adsorption of 4‐TBP on the rutile TiO₂(110) surface in DSC was studied by using the density functional theory at DFT/B3LYP level. By comparing the results with those attained from experiments, it was concluded that the 4‐TBP could chemiadsorb on the incompletely covered surface Ti atoms in the electrode. The probable mechanism of compressed recombination by coordinated 4‐TBP in DSC was proposed.     

New Amphiphilic Polypyridyl Ruthenium（Ⅱ） Sensitizer and Its Application in Dye-Sensitized Solar Cells

Amphiphilic polypyridyl mthenium（Ⅱ） complex cis-di（isothiocyanato）（4,4＇-di-tert-butyl-2,2＇-bipyridyl）（4,4＇- dicarboxy-2,2＇-bipyridyl）ruthenium（Ⅱ）（K005） has been synthesized and characterized by cyclic voltammetry, ^1H NMR, UV-Vis, and FT-IR spectroscopies. The sensitizer sensitizes TiO2 over a notably broad spectral range due to its intense metal-to-ligand charge-transfer （MLCT） bands at 537 and 418 nm. The photophysical and photochemical studies of K005 were contrasted with those of cis-Ru（dcbpy）2（NCS）2, known as the N3 dye, and the amphiphilic ruthenium（Ⅱ） dye Z907. A reversible couple at E1/2=0.725 V vs. saturated calomel electrode （SCE） with a separation of 0.08 V between the anodic and cathodic peaks, was observed due to the Ru^Ⅱ/Ⅲ couple by cyclic voltammetry. Furthermore, this amphiphilic ruthenium complex was successfully used as sensitizers for dye-sensitized solar cells with the efficiency of 3.72% at the 100 mW·cm^-2 irradiance of air mass 1.5 simulated sunlight without optimization of TiO2 films and the electrolyte.     

Enhanced Anodic Electrochemiluminescence of Dissolved Oxygen with 2‐(Dibutylamino) ethanol at TiO2 Nanoparticles Modified Platinum Electrode for Dopamine Detection

The anodic electrochemiluminescence (ECL) of dissolved oxygen with 2‐(dibutylamino) ethanol (DBAE) on platinum electrode has been reported previously by our group. Interestingly, the ECL intensity can be greatly amplified at TiO₂ nanoparticles modified platinum electrode (TiO₂/Pt), which is due to the catalytic effect of TiO₂ nanoparticles to electrochemical oxidation of DBAE. It is the first case to obtain the enhanced ECL from luminophor by electrochemical catalysis of co‐reactant. The enhanced anodic ECL intensity can be quenched by dopamine sensitively. And the ECL intensity versus the logarithm of concentration of dopamine was linear over the 4.0×10^?12–1.8×10^?8 M (R²=0.9957), with the limit of detection of 2.7×10^?12 M (S/N=3).     

Fabrication of Heterostructured Fe2TiO5–TiO2 Nanocages with Enhanced Photoelectrochemical Performance for Solar Energy Conversion

Photocatalysts with well‐designed compositions and structures are desirable for achieving highly efficient solar‐to‐chemical energy conversion. Heterostructured semiconductor photocatalysts with advanced hollow structures possess beneficial features for promoting the activity towards photocatalytic reactions. Here we develop a facile synthetic strategy for the fabrication of Fe₂TiO₅–TiO₂ nanocages (NCs) as anode materials in photoelectrochemical (PEC) water splitting cells. A hydrothermal reaction is performed to transform MIL‐125(Ti) nanodisks (NDs) to Ti–Fe–O NCs, which are further converted to Fe₂TiO₅–TiO₂ NCs through a post annealing process. Owing to the compositional and structural advantages, the heterostructured Fe₂TiO₅–TiO₂ NCs show enhanced performance for PEC water oxidation compared with TiO₂ NDs, Fe₂TiO₅ nanoparticles (NPs) and Fe₂TiO₅–TiO₂ NPs.     

Photoinduced Charge Separation in an Aqueous Phase Using Nanoporous TiO2 Film and a Quasi‐Solid Made of Natural Products

Solar cells comprised of nanoparticulate TiO₂ porous film photosensitized with an adsorbing dye have been utilized as photoinduced charge separation systems in aqueous media with the view to forming future artificial photosynthetic systems able to create fuels from solar energy and water. The photoinduced charge separation of the sensitized TiO₂ cell in a quasi‐solid, made from agarose or κ‐carrageenan, was investigated.

I–V curves under 98 mW · cm⁻² irradiation of ITO/TiO₂/Ru(dcbpy)₂(NCS)₂. Electrolyte: 0.1 M LiI/0.01 M I₂ in a quasi‐solid of 0.2 wt.‐% gelatin containing a large excess of water.     

染料敏化太阳能电池TiO2电极的制备及电解质的影响

采用溶胶-凝胶水热法制备了锐钛矿型纳米晶TiO₂薄膜电极,在乙二醇碳酸酯(EC)/1,2-丙二醇碳酸酯(PC)电解液体系中,研究了I₂和KI含量对电极光电性能的影响,发现随着电解液中I₂含量的增加,电池的短路光电流呈现先增加后减小的趋势,但光电流增加和减少的幅度并不大,同时体系的暗电流不断增加,光电压不断下降;随着电解液中KI含量的增加,电池的短路光电流也不断增加,当KI的含量大于0.2 mol/L时,电池的短路光电流的增加的趋势减缓.并对电解液中I₂和KI含量对电池光电性能影响的原因进行了初步的探讨.     

Brookite TiO2 Nanoparticle Films for Dye‐Sensitized Solar Cells

Brookite TiO₂ nanoparticles have been synthesized at low temperature by a soft solution growth method and have been used as building blocks to prepare pure brookite nanoparticle porous films. The film brookite structure was confirmed by XRD and Raman spectroscopy. By spectrophotometry, it was shown that the films had a direct band gap of 3.4 eV. After sensitization by the N719 dye, efficient cells have been produced. A best overall conversion efficiency of 5.97 %, without a scattering layer, was found for the larger TiO₂ starting nanoparticles. The cell open‐circuit voltage was improved compared with that of anatase cells and a lower electron diffusion coefficient was found in the photoanodes made of smaller brookite particles. Lanthanum‐doped brookite nanoparticle films were also studied. They showed a marked decreased in the amount of dye loading, and hence, the solar cells had a reduced current density that was not compensated for by the increased open‐circuit voltage of the cells.     

Cyclometalated Ruthenium(II) Complexes Featuring Tridentate Click‐Derived Ligands for Dye‐Sensitized Solar Cell Applications

A series of heteroleptic bis(tridentate) Ru^II complexes featuring N^C^N‐cyclometalating ligands is presented. The 1,2,3‐triazole‐containing tridentate ligands are readily functionalized with hydrophobic side chains by means of click chemistry and the corresponding cyclometalated Ru^II complexes are easily synthesized. The performance of these thiocyanate‐free complexes in a dye‐sensitized solar cell was tested and a power conversion efficiency (PCE) of up to 4.0 % (J_sc=8.1 mA cm^?2, V_oc=0.66 V, FF=0.70) was achieved, while the black dye ((NBu₄)₃[Ru(Htctpy)(NCS)₃]; Htctpy=2,2′:6′,2′′‐terpyridine‐4′‐carboxylic acid‐4,4′′‐dicarboxylate) showed 5.2 % (J_sc=10.7 mA cm^?2, V_oc=0.69 V, FF=0.69) under comparable conditions. When co‐adsorbed with chenodeoxycholic acid, the PCE of the best cyclometalated dye could be improved to 4.5 % (J_sc=9.4 mA cm^?2, V_oc=0.65 V, FF=0.70). The PCEs correlate well with the light‐harvesting capabilities of the dyes, while a comparable incident photon‐to‐current efficiency was achieved with the cyclometalated dye and the black dye. Regeneration appeared to be efficient in the parent dye, despite the high energy of the highest occupied molecular orbital. The device performance was investigated in more detail by electrochemical impedance spectroscopy. Ultimately, a promising Ru^II sensitizer platform is presented that features a highly functionalizable “click”‐derived cyclometalating ligand.     

Enhanced Visible‐Light‐Induced Photoelectrocatalytic Degradation of Methyl Orange by CdS Sensitized TiO2 Nanotube Arrays Electrode

In this work, CdS sensitized TiO₂ nanotube arrays (CdS/TiO₂NTs) electrode was synthesized with the CdS deposition on the highly ordered titanium dioxide nanotube arrays (TiO₂NTs) by sequential chemical bath deposition method (S‐CBD). The as‐prepared CdS/TiO₂NTs was characterized by field‐emission scanning electron microscopy (FE‐SEM) and X‐ray diffraction (XRD). The results indicated that the CdS nanoparticles were effectively deposited on the surface of TiO₂NTs. The amperometric I‐t curve on the CdS/TiO₂NTs electrode was also presented. It was found that the photocurrent density was enhanced significantly from 0.5 to 1.85 mA/cm² upon illumination with applied potential of 0.5 V at the central wavelength of 253.7 nm. The photoelectrocatalytic (PEC) activity of the CdS/TiO₂NTs electrode was investigated by degradation of methyl orange (MO) in aqueous solution. Compared with TiO₂NTs electrode, the degradation efficiencies of CdS/TiO₂NTs electrode increased from 78% to 99.2% under UV light in 2 h, and from 14% to 99.2% under visible light in 3 h, which was caused by effective separation of the electrons and holes due to the effect of CdS, hence inhibiting the recombination of electron/hole pairs of TiO₂NTs.     

Enhanced Charge Separation Efficiency in Pyridine‐Anchored Phthalocyanine‐Sensitized Solar Cells by Linker Elongation

A series of zinc phthalocyanine sensitizers ( PcS22 – 24 ) having a pyridine anchoring group are designed and synthesized to investigate the structural dependence on performance in dye‐sensitized solar cells. The pyridine‐anchor zinc phthalocyanine sensitizer PcS23 shows 79 % incident‐photon to current‐conversion efficiency (IPCE) and 6.1 % energy conversion efficiency, which are comparable with similar phthalocyanine dyes having a carboxylic acid anchoring group. Based on DFT calculations, the high IPCE is attributed with the mixture of an excited‐state molecular orbital of the sensitizer and the orbitals of TiO₂. Between pyridine and carboxylic acid anchor dyes, opposite trends are observed in the linker‐length dependence of the IPCE. The red‐absorbing PcS23 is applied for co‐sensitization with a carboxyl‐anchor organic dye D131 that has a complementary spectral response. The site‐selective adsorption of PcS23 and D131 on the TiO₂ surface results in a panchromatic photocurrent response for the whole visible‐light region of sun light.