Synthesis and Computational Characterization of Organic UV-Dyes for Cosensitization of Transparent Dye-Sensitized Solar Cells

The fabrication of colorless and see-through dye-sensitized solar cells (DSCs) requires the photosensitizers to have little or no absorption in the visible light region of the solar spectrum. However, a trade-off between transparency and power conversion efficiency (PCE) has to be tackled, since most transparent DSCs are showing low PCE when compared to colorful and opaque DSCs. One strategy to increase PCE is applying two cosensitizers with selective conversion of the UV and NIR radiation, therefore, the non-visible part only is absorbed. In this study, we report synthesis of novel five UV-selective absorbers, based on diimide and Schiff bases incorporating carboxyl and pyridyl anchoring groups. A systematic computational investigation using density functional theory (DFT) and time-dependent DFT approaches was employed to evaluate their prospect of application in transparent DSCs. Experimental UV/Vis absorption spectra showed that all dyes exhibit an absorption band covering the mid/near-UV region of solar spectrum, with a bathochromic shift and a hyperchromic shifts for Py-1 dye. Computational results showed that the studied dyes satisfied the basic photophysical and energetics requirements of operating DSC as well as the stability and thermodynamical spontaneity of adsorption onto surface of TiO₂. However, results revealed outperformance of the thienothiophene core-containing Py-1 UV-dye, owing to its advantageous structural attributes, improved conjugation, intense emission, large Stokes shift and maximum charge transferred to the anchor. Chemical compatibility of Py-1 dye was then theoretically investigated as a potential cosensitizer of a reference VG20-C2 NIR-dye. By the judicious selection of pyridyl anchor-based UV-absorber (Py-1) and carboxyl anchor-based NIR-absorber (VG20), the advantage of the optical complementarity and selectivity of different TiO₂-adsorption-site (Lewis- and Bronsted-acidic) can be achieved. An improved overall PCE is estimated accordingly.     

2,6-位取代的BODIPY染料敏化剂的合成及其性能

设计合成了3种新型基于氟化硼络合二吡咯甲川(BODIPY)衍生物的D-π-A型光敏染料CB1~CB3,其结构为:BODIPY核为桥联基团、N-苯基咔唑以不同位点连接BODIPY的2-位作为电子给体单元、氰乙酸连接于BODIPY的6-位作为电子受体单元。运用1H,13C NMR以及MALDI-TOF-MS对所合成的染料CB1~CB3进行了结构表征和确证。对3种染料CB1~CB3进行了UV-Vis和荧光等光物理特性、电化学行为、光伏性能研究,并通过DFT理论计算深入研究了其分子的几何结构与性能之间的关系。3种染料的吸收光谱主要位于420~600 nm波段,LUMO能级在3.7 eV左右,HOMO能级在5.2 eV左右。N-苯基咔唑2-位与BODIPY相连的CB2,因更平整的分子结构和更为适合的共轭长度,具有更为优良的光谱吸收和分子内电荷迁移性能,因而表现出良好的光伏性能:在AM1.5(100 m W·cm-2)的光强下,CB2敏化电池的开路电压(Voc)为550 m V,电流密度(Jsc)为3.71 m A·cm-2,填充因子(FF)为0.73,总光电转换效率(PCE)为1.49%。     

2,6-位取代的BODIPY染料敏化剂的合成及其性能

设计合成了3种新型基于氟化硼络合二吡咯甲川(BODIPY)衍生物的D-π-A型光敏染料CB1~3,其结构为:BODIPY核为桥联基团、N-苯基咔唑以不同位点连接BODIPY的2-位作为电子给体单元、氰乙酸连接于BODIPY的6-位作为电子受体单元。运用1H,13C NMR以及MALDI-TOF-MS对所合成的染料CB1-CB3进行了结构表征和确证。对3种染料CB1~CB3进行了UV-Vis和荧光等光物理特性、电化学行为、光伏性能研究,并通过DFT理论计算深入研究了其分子的几何结构与性能之间的关系。3种染料的吸收光谱主要位于420~600 nm 波段,LUMO能级在3.7 eV左右,HOMO能级在5.2 eV左右。N-苯基咔唑2-位与BODIPY相连的CB2,因更平整的分子结构和更为适合的共轭长度,具有更为优良的光谱吸收和分子内电荷迁移性能,因而表现出良好的光伏性能:在AM1.5(100 mW·cm^-2)的光强下,CB2敏化电池的开路电压(V_oc)为550 mV,电流密度(J_sc)为3.71 mA· cm^-2,填充因子(FF)为0.73,总光电转换效率(PCE)为1.49%。     

一种含氧供电基团的染料合成及其光伏性能

以对溴苯酚为原料,经碘丁烷的烷基化后,与硼酸三甲酯反应生成对丁氧基苯硼酸.环戊二噻吩经N-溴代丁二酰亚胺(NBS)的溴化和Vilsmeier-Haack反应,再与对丁氧基苯硼酸偶联、氰基乙酸缩合,生成目标化合物环戊二噻吩基光敏染料(L1).该化合物是一种以含氧基团为给体,环戊二噻吩作为共轭桥的有机染料,将其制备成有机染料敏化太阳能电池,在AM 1.5,100 mW/cm2的光强下,电池的单色光的光电转换效率(IPCE)值达到62%,开路电压(Voc)为535mV,短路电流密度(Jsc)为6.4mA·cm-2,填充因子(FF)为0.60,总光电转换效率为2.1%.     

金属有机框架在染料敏化太阳能电池中的应用

为了获得高效率的染料敏化太阳能电池,其光阳极应该具有大的比表面积,以吸附足量的染料,获得很强的光捕获能力.从这个角度而言,将具有很大比表面积的金属有机框架材料引入到染料敏化太阳能电池的体系中,无疑是一种有益的探索.本文简介了金属有机框架材料在光伏领域的应用,并重点介绍了我们课题组在利用金属有机框架材料方面进行的一些探索,包括光阳极薄膜的处理、利用金属有机框架材料作为前驱体制备光阳极材料和光散射层.最后,本文对金属有机框架材料应用于染料敏化太阳能电池中的局限性及前景做了简要的展望.     

基于苯并噻二唑的菁染料敏化剂的合成与光伏性能研究

两个新型的基于三苯胺苯并噻二唑的菁染料(I～II)通过含有该单元的苯并[e]吲哚啉乙醛和1,1,2-三甲基-3-丁 基-5-羧基-3H-吲哚碘盐的Knoevenagel缩合反应合成, 其结构用核磁和高分辨质谱进行了表征|对两个菁染料敏化剂的光物理、电化学性能和太阳能电池的光伏性能进行了系统研究. 在AM1.5G标准光源下, 两个染料的最高入射单色光子-电子转化效率值(IPCE值)均超过57%, 其光电转换效率分别为2.59%和3.28%.     

染料敏化太阳电池电解质

染料敏化太阳电池是新一代的太阳电池,有着巨大的应用前景。其中电解质体系是电池组成的主要部分,对电池的性能有着重要的影响。本文介绍了染料敏化太阳电池的基本原理,详细评述了近几年国内外学者对染料敏化太阳电池用电解质体系的研究进展情况,根据电解质的存在状态将其分为液态、准固态和固态三大类并逐一进行介绍,最后对该领域的前景进行了展望。     

有机染料及其在染料敏化太阳电池中的应用

在染料敏化太阳电池中,染料敏化剂分成无机染料与有机染料两大类。无机染料受稀有金属钌的制约而成本较高,开发有机染料是降低染料敏化太阳电池成本的有效手段,成为目前研究的热点。本文从有机染料敏化剂的分子设计入手,简述了染料敏化太阳电池中有机染料敏化剂的基本结构,将有机染料敏化剂分为吲哚啉类染料、香豆素类染料、三苯胺类染料、菁...     

Naphthyl and Thienyl Units as Bridges for Metal-Free Dye-Sensitized Solar Cells

A series of new organic dyes, comprising a naphthyl moiety as a π-conjugated bridge, different amines as donors, and a cyanoacrylic acid group as an electron acceptor and anchoring group, have been designed and synthesized for applications in dye-sensitized solar cells (DSSCs). One of the compounds was also characterized by single-crystal X-ray structural analysis. All of the dyes exhibited maximum absorptions in the range of 371–441 nm. The short-circuit photocurrent density, open-circuit voltage, and fill factor (FF) values of the devices are in the range of 6.13–10.90 mA cm⁻², 0.62–0.69 V, and 0.62–0.67, respectively, corresponding to an overall conversion efficiency of 2.76–4.55 %. The conversion efficiency reached 38–62 % of that of a N719-based device (7.31 %) fabricated and measured under similar conditions. Steric congestion between the naphthyl and aromatic moieties jeopardizes charge transfer from the donor to the acceptor. Insertion of an alkenyl entity between the naphthyl entity and the aromatic ring alleviates steric congestion and leads to longer wavelength electronic absorption spectra.     

两种锌卟啉聚合物自组装染料敏化太阳能电池

合成了2种新型锌卟啉并与金属Mn构建配位聚合物(CPsx,x=1,2)。2种配位聚合物与锚定卟啉(ZnPA)通过金属-配体轴向配位自组装染料敏化太阳能电池(DSSC)。测试结果表明自组装电池具有较好的光电转换效率,特别是基于CPs2的装置具有较高的短路电流和转换效率。我们还对其光学、电化学及光电性能进行了研究,并通过透射电镜(TEM)对自组装体有效敏化在TiO_2电极上进行验证。     

Meso-Substituted Tetrabenzotriazaporphyrins for Dye-Sensitized Solar Cells

A novel tetrabenzotriazaporphyrin (TBTAP) bearing an anchoring carboxy-phenyl group at the meso-carbon position ( TT260 ) was synthesized by an efficient method, which involves the crossover condensation between phthalonitrile and aminoisoindoline precursors. Its optical and electrochemical properties were also investigated together with its use as sensitizer in dye-sensitized solar cells (DSSCs). The performance of TT260 was compared with a benchmark molecule TT1 , bearing similar bulky tert-butyl groups at the periphery. The device, which is the first ever example of meso-substituted TBTAP-based DSSC, exhibits a modest maximum power conversion efficiency of 2.4±0.1 % under one-sun conditions.     

Adamantyl Side Chains as Anti-Aggregating Moieties in Dyes for Dye-Sensitized Solar Cells

Designing and evaluating novel dye concepts is crucial for the development of the field of dye-sensitized solar cells (DSSCs). In our recent report, the novel concept of tethering the anti-aggregation additive chenodeoxycholic acid (CDCA) to dyes for DSSC was introduced. Based on the performance improvements seen for this modification, the aim of this study is to see if a simplified anti-aggregation unit could achieve similar results. The following study reports the synthesis and photovoltaic characterization of two novel dyes decorated with the steric ethyladamantyl moiety on the π-spacer, and on the triarylamine donor. This modification is demonstrated to be successful in increasing the photovoltages in devices employing copper-based electrolytes compared to the non-modified reference dye. The best photovoltaic performance is achieved by a device prepared with the adamantyl decorated donor dye and CDCA, this device achieves a power conversion efficiency of 6.1 % (Short-circuit current=8.3 mA cm⁻², Open-circuit voltage=1054 mV, Fill factor=0.69). The improved photovoltaic performance seen for the adamantyl decorated donor demonstrate the potential of ethyladamantyl side chains as a tool to ensure surface protection of TiO₂.     

染料敏化太阳能电池掺杂TiO2纳晶光阳极

染料敏化太阳能电池（dye-sensitized solar cells, DSC）效率高、制作简单、成本低,因此被认为是最有希望的第三代太阳能电池。DSC光阳极的主要作用是吸附染料、传输电子和提供电解质扩散通道,因此对DSC光电性能具有决定性作用。近年来,通过掺杂调控TiO₂光阳极的电子特性,从而提高DSC的光电效率受到广泛关注。本文对掺杂TiO₂光阳极的研究现状进行了综述,重点分析了非金属元素、过渡金属元素及主族元素的掺杂对TiO₂光阳极的能带结构、光吸收特性、染料吸附量、电子传输和界面复合过程以及所组装DSC光电性能的影响,分析了非金属元素共掺杂的协同效应。同时,对稀土元素掺杂TiO₂作为光谱转换材料提高DSC光吸收效率和光电转换效率进行了探讨,最后论文对掺杂TiO₂光阳极今后的研究重点和研究方向进行了展望。     

一种天线分子与卟啉染料自组装在染料敏化太阳能电池中的应用

以卟啉分子H2-pTCPP作为基础染料,通过配位自组装的方法将天线分子S3修饰到染料结构中。结果表明经天线分子修饰后染料敏化太阳能电池器件的整体性能得到了极大的改善。天线效应有效地提高了器件的光子捕获能力,光电流得到了显著的提高,并且电荷复合行为也得到了明显的抑制。基于H2-pTCPP的电池器件显示了1.18%的转换效率,而经过天线分子修饰后的Mn-pTCPP+S3显示了2.64%的转换效率,性能提高了1.2倍。     

锌卟啉自组装在染料敏化太阳能电池中的应用

制备了2种锌卟啉天线分子P2与P3,并通过自组装的方法成功地将这些天线分子应用到了染料敏化太阳能电池之中。与传统的D-π-A结构的染料相比,这种策略显示出了明显的优势：可以避免复杂的合成步骤,还可以通过调节天线分子和锚固基团的结构去改善染料的光子捕获能力并减少电荷复合行为。当4-吡啶-4-基苯甲酸（A）作为锚固基团时,经过分子自组装之后,基于A-P2的电池器件显示出了1.68%的转换效率,开路电压为526 mV,短路电流密度为5.39 mA·cm^-2,这充分说明了自组装策略在染料敏化太阳能电池中得到了很好的应用。而基于A-P3的电池器件能量转换效率只有0.79%,这可能主要是因为天线分子P3较大的位阻减小了染料吸附量的原因造成的。我们另外也测试比较了它们在光学、电化学、光伏性能等方面的差异。     

不同受体结构染料共敏化对染料敏化太阳电池性能的影响

为了拓宽染料敏化太阳电池对太阳光谱的响应范围,提高电池的光电转换效率,将两种含有不同受体结构（绕丹宁-3-乙酸基（RA）和氰基丙烯酸基（CA））的三苯胺染料（TR1和TC1）进行共敏化。TR1染料平伏吸附在TiO₂表面,而TC1染料直立吸附在TiO₂表面。将两种染料按照不同摩尔比共敏化TiO₂后,TC1占据TR1的部分位置,拓展光谱的同时也抑制了电荷复合,电子寿命较TR1敏化的太阳电池长。在TR1与TC1摩尔比为5：5的共敏剂溶液敏化的共敏电池器件中,短路光电流密度（J_sc）为11.7 mA/cm²,开路电压（V_oc）为704 mV,填充因子（FF）为0.73,光电转换效率（η）为6.03%。该结果明显优于单一染料敏化的电池器件。     

染料敏化太阳电池钌系敏化剂

钌系敏化剂是染料敏化太阳电池（DSSC）研究最早也最成功的敏化剂类型之一,最高光电转换效率已达到11%以上。研究总结钌系敏化剂的结构、谱学性质、电化学性质与其光电转换性能之间的构效关系,对于设计合成新的具有更高性能的敏化剂、推进DSSC的实用化进程具有十分重要的意义。本文综述了钌系敏化剂的研究进展,将这类敏化剂按结构和性质进行分类,讨论了其分子结构、电子结构、谱学性质、电化学性质对其光吸收能力、电子注入效能、电荷传输与复合等因素的影响,并对其光电转换性能进行了详细评述,总结了其结构与光电转换性能之间的构效关系,概括了高效钌系敏化剂的结构特征,为更高效敏化剂的设计合成提供了有价值的参考。     

A Silicon-based Imidazolium Ionic Liquid Iodide Source for Dye-Sensitized Solar Cells

Room temperature molten salt 1‐methyl‐3‐(trimethylsilyl)methyl‐imidazolium iodide (MSII) was used for iodide sources in dye‐sensitized solar cells with an organic sensitizer 2‐cyano‐3‐[5‐[4‐[3‐[4‐(4‐(N,N‐bis(4‐methoxyphenyl)amino)phenyl)phenyl]‐2,5‐di‐n‐butyl‐pyrrolo[3,4‐c]pyrrole‐1,4‐dione]phenyl]furan‐2‐yl] acrylic acid (DPP‐I) as light harvester. With an optimized electrolyte (MSII:I₂:BI:GuNCS?24:2:2:0.4, BI and GuCNS are short for benzimidazole and guanidine thiocyanate, respectively), photovoltaic parameters (J_sc, V_oc, and ff) of device are 8.97 mA·cm^?2, 600 mV and 0.61, respectively, yielding a maximum overall photo‐to‐energy conversion ef?ciency (η) of 3.23%. And then the charge‐transfer mechanism of devices was deeply analyzed with electrochemical impedance spectroscopy (EIS) in the dark.     

基于p型光电极的染料敏化太阳能电池研究进展

基于p型光电极的染料敏化太阳能电池是一种受到广泛关注的新型太阳能电池。根据电池的结构不同可以将其分为p型和p-n叠层型染料敏化太阳能电池。其中p-n型叠层染料敏化太阳能电池的理论光电效率可以达到43%,高于传统的基于n型TiO₂光阳极的染料敏化太阳能电池理论效率（30%）,引起了科学界的高度关注。本文将总结基于p型光电极染料敏化太阳能电池（p型和p-n型叠层器件）的研究成果,重点介绍用于p型和p-n型叠层染料敏化太阳能电池的电极材料,染料及电解质的研究进展;同时总结目前该类电池发展中亟需解决的问题以及进一步提高器件效率的途径。