聚合溶液pH值对染料敏化太阳电池中聚吡咯对电极结构和性能的影响

电化学合成聚吡咯(PPy)时,聚合电解液的pH值对PPy薄膜的形貌和性质有较大的影响,进而影响PPy薄膜对I-/I3-的电催化活性以及基于PPy对电极(CE)的染料敏化太阳电池(DSSCs)的光电转换性能.本文采用电化学恒电位方法,在掺杂氟的SnO2(FTO)导电玻璃上合成出了对甲苯磺酸根离子掺杂的聚吡咯(PPyTsO)电极,并将其作为DSSCs的对电极.通过改变吡咯聚合时聚合电解液的pH值,借助扫描电镜(SEM)、紫外-可见(UV-Vis)吸收光谱、X-射线光电子能谱(XPS)和循环伏安(CV)等表征技术,详细探讨了聚合溶液pH值对PPy CE形貌、结构及其对I-/I3-的电催化性能的影响.研究发现在pH 2.0下合成的聚吡咯对阴离子掺杂率最高且链共轭性最佳,具有对I-/I3-氧化还原介质最强的催化能力,基于此PPy CE的电池光电转化效率也最高.pH值太大或太小都不利于生成具有高掺杂率和高催化活性的PPy电极,组装成DSSCs后的光电转换效率也较低.     

Fe/Cu修饰氮掺杂碳纳米管的构筑及催化性能

通过简单的原位化学合成法结合离子交换法制备了Cu修饰氮掺杂碳（Cu-N-C）和Fe/Cu修饰氮掺杂碳纳米管（Fe/Cu-N-C/CNT）,并系统评估了2种催化剂作为染料敏化太阳能电池（dye-sensitized solar cells,DSSCs）对电极在I₃^-/I^-体系中的电化学特性和光伏性能。采用X射线衍射（XRD）、拉曼（Raman）、X射线光电子能谱（XPS）和场发射扫描电镜（FESEM）对合成的催化剂进行组分和形貌表征。结果表明：纳米管状的Fe/Cu-N-C/CNT的石墨化程度比纳米颗粒状的Cu-N-C更高,更有利于I₃^-还原反应中电荷的传输。光伏性能测试结果表明：基于Fe/Cu-N-C/CNT对电极的DSSCs的光电能量转换效率（power conversion efficiency,PCE）达到7.55%,高于相同测试条件下Cu-N-C（6.99%）和Pt（6.76%）对电极的PCE。50圈连续循环伏安测试结果表明：Fe/Cu-N-C/CNT催化剂具有比Cu-N-C更好的电化学稳定性。     

聚合时间对染料敏化太阳能电池中聚苯胺对电极结构和性能的影响

采用恒电压方法, 以掺杂氟的SnO₂ (FTO)导电玻璃为基底, 采用不同的聚合时间制备SO₄^2?掺杂的聚苯胺对电极(PANI CEs). 利用扫描电子显微镜(SEM)、紫外-可见(UV-Vis)吸收光谱、循环伏安法(CV)和电化学阻抗谱(EIS)等技术详细研究了聚合时间对PANI CEs的表面形貌、结构(如掺杂度、共轭性、氧化态等)和对I^?/I^3?的催化活性的影响. SEM结果表明PANI在FTO上的生长分两个阶段. 适当增加聚合时间可以增加PANI CEs的比表面积, 为催化I^?/I^3?反应提供更多的活性位点, 同时聚苯胺链的共轭性、半氧化态聚苯胺(EB)结构的含量和对阴离子SO₄^2?的掺杂度会随着增加, 进而PANI 的导电率也逐渐增大. 然而, 聚合时间过长会引起薄膜厚度的增加和氧化结构的过多, 使PANI CEs的导电率降低, 电子在PANI 薄膜中的传输阻抗增加, 进而影响其对I^?/I^3?的催化性能. 聚合时间为300 s 时制备出的PANI 薄膜作为染料敏化太阳能电池(DSSCs)对电极和以D149 为染料时, 获得的最高电池光电转换效率为5.30%, 可达到基于Pt 对电极电池效率的88%. 因此, 通过电化学方法制备的PANI CEs有望代替贵金属Pt CEs用于DSSCs中.     

氧化石墨烯/聚吡咯插层复合材料的制备和电化学电容性能

以FeCl₃-甲基橙(MO)为模板, 通过化学原位聚合法成功制备出氧化石墨烯/聚吡咯(GO/PPy)插层复合材料. 采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、扫描电镜(SEM)和透射电镜(TEM)等测试技术对复合材料进行物性表征. 此外, 利用循环伏安、恒电流充放电和交流阻抗测试方法对复合材料在两种不同水系电解液(1 mol·L^-1 Na₂SO₄和1 mol·L^-1 H₂SO₄)中的电化学性能进行了研究. 结果显示: 氧化石墨烯和聚吡咯表现出各自优势并发挥协同作用, 使得GO/PPy插层复合材料在中性和酸性电解液中都显示出可观的比电容. 电流密度为0.5 A·g^-1时, GO/PPy 插层复合材料在Na₂SO₄和H₂SO₄电解液中的比电容分别为449.1 和619.0 F·g^-1, 明显高于纯PPy的比电容. 经过800 次循环稳定性测试后, 两种不同电解液中, 复合材料初始容量的保持率分别为92%和62%. 其中酸性电解液体系中初始容量更大, 而中性溶液中具有更稳定的循环性能.     

染料敏化太阳能电池中大孔TiO2薄膜电极的制备及应用

采用溶胶-凝胶水热法制备了TiO₂纳晶薄膜电极，晶型为锐钛矿型。为了提高电极的光电性能，利用聚苯乙烯小球做造孔剂，制备了含有大孔隙的TiO₂纳晶薄膜电极，孔径约为200 nm，该电极具有较好的光漫反射性能，更重要的是球形大孔的存在，提高了凝胶电解质在TiO₂薄膜电极中的渗透和I₃^-离子的扩散性能，与不含大孔的TiO₂电极相比，电池的短路光电流提高约2 mA·cm^-2，光电转换效率提高0.6%。     

于离子液体和介孔SBA-15为支架的准固态染料敏化太阳能电池

利用介孔SBA-15作为支架材料制备了一类准固态电解质。离子电导测试表明SBA-15的引入增加了准固态电解质的电导率。通过拉曼光谱证实了聚碘离子I₃^-和I₅ ^-的存在，并且通过计算表明聚碘离子的扩散系数是I^-的两倍。经过组装优化，基于该准固态电解质的电池在AM1.5，75 mW cm^-2的光强下可得到4.3%的光电转化效率。     

ZnFe2O4/CNFs钛网基对电极膜厚对染料敏化太阳能电池性能的影响

通过静电纺丝和简单的一步水热法合成了碳纳米纤维（CNFs）负载的ZnFe₂O₄纳米颗粒（ZnFe₂O₄/CNFs）,并将其刮涂在钛网基底上作为染料敏化太阳能电池（DSSCs）的对电极进行组装测试,电池表现出优异的电化学性能。我们着重研究了不同膜厚对电极对DSSCs光电性能的影响。经过反复测试结果表明,当ZnFe₂O₄/CNFs复合电极材料膜厚为12 μm时存在最高的光电转换效率8.60%。     

球形微粒Co3O4电极催化氧化硫离子

尝试用氨蒸发诱导合成方法在石墨小片上生长球形Co₃O₄微粒, 并用其制备电极且进行S^2-的电化学氧化研究. 用极化曲线、恒电位技术等电化学方法考察了Co₃O₄电极对S^2-的电化学氧化的催化性能, 发现Co₃O₄电极对电化学氧化S^2-具有优异的催化性能, 极大地促进了-0.40 V 附近S^2-向含硫的酸根离子和低级多硫离子的转变, 电流密度最大可以达到580 mA·cm^-2. 恒电位极化表明电极的电催化稳定性良好; 电化学阻抗谱(EIS)测试显示Co₃O₄在碱性S^2-电解液中的电荷转移电阻很小, 这从电化学动力学角度解释了它对S^2-具有良好的催化性能.     

染料敏化太阳能电池对电极La2Mo2O7复合MWCNTs非Pt催化剂的制备与性能

通过高温固相法对醋酸镧（C₆H₉O₆La·xH₂O）与高钼酸铵（（NH₄）₆Mo₇O₂₄·4H₂O）在一定条件下热解制备非Pt催化剂La₂Mo₂O₇（La₂O₃-2MoO₂）。进一步采用2种方法将La₂Mo₂O₇与多壁碳纳米管（MWCNTs）进行复合,一种是将La₂Mo₂O₇喷涂到MWCNTs表层之上得到La₂Mo₂O₇/MWCNTs,另一种是将两者均匀混合掺杂得到La₂Mo₂O₇@MWCNTs,再将上述2种复合材料应用于染料敏化太阳能电池对电极进行相应研究。通过扫描电子显微镜（SEM）表征了复合催化材料的微观形貌,X射线衍射（XRD）确定了微观结构。采用电流密度-光电压曲线、循环伏安,交流阻抗以及塔菲尔极化分析了材料的光电性能。实验结果表明在电解液I₃^-/I^-中,基于La₂Mo₂O₇/MWCNTs与La₂Mo₂O₇@MWCNTs的对电极,相同的条件下在光电池中获得的光电转换效率分别为6.09%和4.84%,明显高于MWCNTs的3.94%和La₂Mo₂O₇的0.87%。电极性能的提高可归因于La₂Mo₂O₇复合催化剂相对大的比表面积和高导电性。     

MoS2/CNFs对电极膜厚对染料敏化太阳能电池性能影响

通过静电纺丝技术和水热法成功获得了碳纳米纤维负载二维层状硫化钼（MoS₂/CNFs）,将其作为对电极组装的染料敏化太阳能电池（DSSCs）表现出优异的电化学特性。在DSSCs制备过程中,对电极膜厚对电池性能有很大影响,所以本文重点探究了喷涂法制备的对电极膜厚对其组装的染料敏化电池光电性能影响,获得最佳对电极膜厚。实验结果表明当MoS₂/CNFs复合对电极材料膜厚为8 μm时,电池光电转换效率达到最大值7.78%。     

Transparent Metal Selenide Alloy Counter Electrodes for High‐Efficiency Bifacial Dye‐Sensitized Solar Cells

The exploration of cost‐effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye‐sensitized solar cells (DSSCs). Transparent counter electrodes based on binary‐alloy metal selenides (M‐Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution‐based method and employed in efficient bifacial DSSCs. Owing to superior charge‐transfer ability for the I^?/I₃^? redox couple, electrocatalytic activity toward I₃^? reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30 % and 4.63 % for Co_0.85Se, 7.85 % and 4.37 % for Ni_0.85Se, 6.43 % and 4.24 % for Cu_0.50Se, 7.64 % and 5.05 % for FeSe, and 9.22 % and 5.90 % for Ru_0.33Se in comparison with 6.18 % and 3.56 % for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels.     

Highly Catalytic Carbon Nanotube/Pt Nanohybrid‐Based Transparent Counter Electrode for Efficient Dye‐Sensitized Solar Cells

Low‐cost transparent counter electrodes (CEs) for efficient dye‐sensitized solar cells (DSSCs) are prepared by using nanohybrids of carbon nanotube (CNT)‐supported platinum nanoparticles as highly active catalysts. The nanohybrids, synthesized by an ionic‐liquid‐assisted sonochemical method, are directly deposited on either rigid glass or flexible plastic substrates by a facile electrospray method for operation as CEs. Their electrochemical performances are examined by cyclic voltammetry, current density–voltage characteristics, and electrochemical impedance spectroscopy (EIS) measurements. The CNT/Pt hybrid films exhibit high electrocatalytic activity for I^?/I₃^? with a weak dependence on film thickness. A transparent CNT/Pt hybrid CE film about 100 nm thick with a transparency of about 70 % (at 550 nm) can result in a high power conversion efficiency (η) of over 8.5 %, which is comparable to that of pyrolysis platinum‐based DSSCs, but lower cost. Furthermore, DSSC based on flexible CNT/Pt hybrid CE using indium‐doped tin oxide‐coated polyethylene terephthalate as the substrate also exhibits η=8.43 % with J_sc=16.85 mA cm^?2, V_oc=780 mV, and FF=0.64, and this shows great potential in developing highly efficient flexible DSSCs.     

Multi-wall carbon nanotube counter electrodes for dye-sensitized solar cells prepared by electrophoretic deposition

In this study, electrophoretic deposition (EPD) was employed to fabricate multi-wall carbon nanotube (MWCNT) counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Firstly, raw MWCNTs were functionalized by means of an acid mixture solution and then subjected to EPD. The results obtained from Raman spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscope, and cyclic voltammogram demonstrated that the defects and open ends on the MWCNTs can be obtained via chemical functionalization and thus facilitate the enhancement in the electrocatalytic activity for I₃⁻ reduction of MWCNT CEs. In addition to optimizing chemical functionalization of MWCNTs surface, the optimal thickness of MWCNT CEs prepared by EPD was also investigated. Additionally, consecutive cyclic voltammetric tests demonstrated that the MWCNT CE fabricated by EPD possessed excellent electrochemical stability. In comparison with MWCNT CEs fabricated by tape-casting approach, MWCNT CEs prepared by EPD presented a superior adhesion between MWCNT deposits and conducting glass substrates. Therefore, MWCNT CEs fabricated by EPD can be of great potential for use in low-cost plastic DSSCs.     

Electrocatalytic Reduction of Oxygen at Anthraquinonedisulfonate/Polypyrrole Composite Film Modified Electrodes and Its Application to the Electrochemical Oxidation of Azo Dye

We report here the electrocatalytic reduction of oxygen on thin anthraquindisulfonate (AQDS)/poplypyrrole (PPy) composite film modified electrodes and its application to the electrooxidation of azo dye‐amaranth. The polymer‐coated cathode exhibited good electrocatalytic activity towards oxygen reduction reaction (ORR), and allowed the formation of strong oxidant hydroxyl radical (^.OH) in the medium via Electro‐Fenton's reaction between cathodically generated H₂O₂ and added or regenerated Fe²⁺. The electrochemical behaviors of ORR in various pH solutions were described using cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometric (CA) techniques. The effect of solution pH on amaranth mineralization by the Fe²⁺/H₂O₂ and Fe³⁺/H₂O₂ electrooxidation systems was studied. In addition, the long‐term electrocatalytic activity and stability of the AQDS/PPy composite film during multiple experimental runs were also examined electrochemically.     

Efficient Counter Electrode Manufactured from Ag2S Nanocrystal Ink for Dye‐Sensitized Solar Cells

It is generally believed that silver or silver‐based compounds are not suitable counter electrode (CE) materials for dye‐sensitized solar cells (DSSCs) due to the corrosion of the I^?/I₃^? redox couple in electrolytes. However, Ag₂S has potential applications in DSSCs for catalyzing I₃^? reduction reactions because of its high carrier concentration and tiny solubility product constant. In the present work, CE manufactured from Ag₂S nanocrystals ink exhibited efficient electrocatalytic activity in the reduction of I₃^? to I^? in DSSCs. The DSSC consisting of Ag₂S CE displayed a higher power conversion efficiency of 8.40 % than that of Pt CE (8.11 %). Moreover, the devices also showed the characteristics of fast activity onset, high multiple start/stop capability and good irradiated stability. The simple composition, easy preparation, stable chemical property, and good catalytic performance make the developed Ag₂S CE as a promising alternative to Pt CE in DSSCs.     

简易合成Cu2SnSe3作染料敏化太阳能电池对电极

采用简易溶剂热法合成直径为150-250 nm的Cu2SnSe3纳米颗粒.以Cu2SnSe3"墨水"为前驱体采用滴落涂布法在掺氟二氧化锡基板上沉积Cu2SnSe3薄膜作为染料敏化太阳能电池(DSSC)对电极.利用场发射扫描电镜(FESEM)、透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、能谱仪(EDS)等对Cu2SnSe3纳米颗粒的形貌、结构和组成进行表征.结果表明:产物纯净无杂项且符合化学计量比.以Cu2SnSe3为对电极的DSSC转化效率为7.75%,与铂对电极DSSC效率相当(7.21%).研究表明,DSSC的光电流密度和影响因子与Cu2SnSe3薄膜厚度密切相关,这是由于不同厚度的Cu2SnSe3薄膜作对电极所对应的催化位置数目和电阻值不同.电化学阻抗谱研究说明,Cu2SnSe3因具有类似铂良好的电催化性能而适合用作染料敏化太阳能电池对电极材料.本文以Cu2SnSe3代替贵金属铂,提供了一种廉价制备高效染料敏化太阳能电池对电极的新方法.     

Preparation of polypyrrole/multi-walled carbon nanotube hybrids by electropolymerization combined with a coating method for counter electrodes in dye-sensitized solar cells

In this work, multi-wall carbon nanotubes coated with polypyrrole (PPy/MWCNT) have been used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). PPy was deposited onto fluorine-doped tin-oxide-coated glass by electrochemical polymerization of pyrrole. Three surfactants were used in the preparation of the hybrids: cationic cetyltrimethylammonium bromide, anionic sodium dodecylbenzenesulfonate (DBSNa), and non-ionic polyoxyethylene sorbitan monolaurate (Tween20). The morphologies of the PPy and PPy/MWCNT hybrids were investigated using scanning electron spectroscopy. Chemical composition of the prepared CEs was determined by X-ray photoelectron spectroscopy and Fourier-transformed infrared spectroscopy. The catalytic activity of the PPy and PPy/MWCNT layers was evaluated using cyclic voltammetry, and the photovoltaic properties of DSSCs with PPy and PPy/MWCNT CEs were characterized using I–V measurements. PPy/MWCNT samples that were prepared by electrochemical polymerization showed the best results when the anionic surfactant DBSNa was used during polymerization. The photoelectric conversion efficiency of PPy/MWCNT prepared by electrochemical polymerization was 2.9%, which was 59% of that of Pt CE (4.9%).     

Copper doped manganese dioxide as counter electrode for dye-sensitized solar cells

Many materials have been tried as the counter electrode (CE) material as a substitute to the noble metal Pt in dye-sensitized solar cells (DSSCs). The CE property is critical to the operation of a DSSC as it catalyzes the reduction of I₃^- ions and retrieves the electrons from the photoanode. Here we have explored the application of manganese dioxide (MnO₂) and copper-doped manganese dioxide (Cu-MnO₂) nanoparticles as CE candidates for DSSCs mainly as low-cost alternatives to Pt. A simple hydrothermal method was followed to synthesize α-MnO2 and Cu-MnO2 nanoparticles at a temperature of 140 °C for 14 h. The nanoparticles were characterized to prove its electrocatalytic abilities for DSSCs. DSSC devices fabricated with 10 wt% Cu-MnO₂ as CE showed the best V_OC of 781 mV, I_SC of 3.69 mA/cm², FF of 0.50, and %PCE of 1.7 whereas Pt as CE showed V_OC of 780 mV, I_SC of 14.8 mA/cm², FF of 0.43, and %PCE of 5.83 under 0.85 Sun. The low-cost feature of using Cu-MnO₂ is encouraging to further study the factors that can improve the efficiency of DSSCs with alternative CEs to conventional Pt electrodes.     

[SiCu(H2O)W11O39]6-在玻碳电极上的多层组装及电催化性能

The electrochemical behavior of SiCu W11 heteropolyacide in acidic aqueous solution was studied. The effect of solution pH on the electrochemical behavior of SiCu W11 was discussed and the mechanism was suggested. New electrode was modified by muhilayer films composed of heteropolyanion (SiCu W11 and cationic polymer poly (diallyldimethylammonium chloride). Cyclic vohammetry showed the uniform growth of the film. The modified electrodes exhibited some special electrochemical properties in the films, different from those in homogeneous aqueous solutions. The effect of pH on the redox behavior of SiCu W11 in the films was discussed in details. The muhilayer film electrodes have an excellent electrocatalytic response to the reduction of BrO3^- and NO2^-.