Effect of the linkage position in ruthenium dyes on the photoelectrochemical perfomance

A series of newly designed Ru-dyes constructed with [Ru(bpy)(bpp)Cl]⁺ (bpp?=?2,6-bis(N-pyrazolyl)pyridine, bpy?=?bipyridine) as template were evaluated by studying the frontier molecular orbital energy, charge distribution, absorption spectrum, light harvesting efficiency, as well as photogenerated current density by using (time-dependent) density functional theory. The calculation results reveal that the light harvesting efficiency and current density are enhanced with only one linkage group attached onto the 4 site of pyridine ligand. Mounting the linkage groups to 3 or 3′ position on pyridine ligand introduces super strong UV absorption.     

Characteristics of Dye-Sensitized Solar Cells Using TiO2 Nanotube Arrays with Large Surface Area by Spin-Coating Nanoparticle

Highly ordered TiO₂ nanotube arrays (TNAs) fabricated by anodization are very attractive for use in dye-sensitized solar cells (DSSCs), because of their superior charge percolation and slow charge recombination. Highly ordered, vertically aligned TNAs have been prepared by three-step anodic oxidation. In this work, we investigated such strategies for improving the efficiency of DSSCs. Based on one of these approaches, oxide semiconductors in the form of a TNA were used as a novel method for improving electron transport through a film. A solution containing an appropriate amount of TiO₂ nanoparticles was prepared, and the mixed slurry was spin-coated on a TNA film. The coated film provided a large surface area for dye adsorption. The DSSCs achieved a light-to-electric energy conversion efficiency of 5.91% under simulated solar irradiation at 100 mW/cm² (AM 1.5).     

Raman spectroscopic study of dye adsorption on TiO2 electrodes of dye-sensitized solar cells

The state of dye adsorption on TiO₂ electrodes in dye-sensitized solar-cell (DSSC) systems is important for its power-conversion efficiency (PCE). We propose a non-destructive and quantitative method to evaluate the amount of adsorbed dye on TiO₂ electrodes by using micro-Raman spectroscopy. The Raman peak intensity ratio of adsorbed dye to TiO₂, I_d/I_t, is defined as a dye adsorption parameter. Based on a comparison between I_d/I_t and the amount of dye evaluated from UV–vis absorption, the quantitativity and reproducibility of our method are verified.We investigated the change of I_d/I_t spatial distribution of TiO₂ electrodes immersed in a dye solution for different time scales. The statistical analysis of I_d/I_t distribution suggests that dyes adsorbed on TiO₂ electrodes with chemical coordination increase at first, and after their saturation, dye aggregations are formed over the chemisorption layer. We also describe the effect of the I_d/I_t distribution on PCE. From a comparison of PCE and I_d/I_t distribution obtained from various immersion processes, it was considered that the PCE of DSSCs can be optimized by minimizing the I_d/I_t dispersion.     

基于咔唑染料敏化剂的合成及电喷雾的DSSC器件制备

本文设计并合成了两个不含金属的新型纯有机染料CBR和CI,用核磁共振、MALDI-TOF、紫外可见吸收光谱和红外光谱对其结构进行了表征,将其应用到以电喷雾法制备Ti O2光阳极的染料敏化太阳能电池(DSSC)中,并测定了染料在Ti O2光阳极上的吸附量.结果表明,在AM 1.5 G的模拟光照下,基于染料CI的电池有更好的器件性能,短路电流(JSC)、开路电压(VOC)、填充因子(FF)和电池效率(η)分别为5.4 m A/cm2、0.73 V、0.58和2.3%.鉴于纯有机染料CBR和CI在350~450 nm区域的吸收较强,选择染料CBR或CI与传统染料N719共敏化,器件效率由5.2%(N719)分别提高到了5.6%(CBR-N719)和6.7%(CI-N719).     

电泳沉积法制备介孔TiO2/单壁碳纳米管薄膜

采用电泳沉积法, 在FTO/介孔TiO2薄膜上制备了介孔TiO2/单壁碳纳米管(SWCNTs)薄膜电极, 用Raman和SEM等手段对薄膜电极进行了表征. 结果表明, SWCNTs已沉积到介孔TiO2薄膜上. 分别用四羧基苯基卟啉(TCPP)和联吡啶钌化合物N719对其进行敏化, 并组装成太阳能电池. 研究结果表明, 与单纯的TiO2粒子膜相比, 介孔TiO2和SWCNTs的紧密结合可使得光生电子更容易传输, 光电转换效率显著提高.     

Azulene – Thiophene – Cyanoacrylic acid dyes with donor-π-acceptor structures. Synthesis,characterisation and evaluation in dye-sensitized solar cells

We report the synthesis of five new azulene containing dyes, having D-π-A type structures. These dyes are synthesised using a sulfonium salt cross-coupling reaction. The dyes have been evaluated spectroscopically, electrochemically, crystallographically, and as sensitizers in dye-sensitized solar cells. We propose a rationale for the dyes' spectroscopic properties and performance in cells, based on conformational data derived from their crystal structures.     

Growth of aligned polypyrrole acicular nanorods and their application as Pt‐free semitransparent counter electrode in dye‐sensitized solar cell

Polypyrrole films on fluorine doped tin oxide (FTO)‐coated glass substrate were prepared in situ by placing FTO/glass substrates where pyrrole was polymerized by methyl orange‐ferric chloride complex. The atomic force microscopy image indicated growth of acicular nanorods of polypyrrole. These films exhibited catalytic activity towards I₃⁻/I⁻ redox couple and have been investigated for counter electrode application in dye‐sensitized solar cell (DSSC). The fabricated DSSC with N719 dye/TiO₂ as photoanode, and PPy/FTO as counter electrode shows ~1.7% efficiency.     

Recent Progress in the Application of Polyoxometalates for Dye‐sensitized/Organic Solar Cells

At present, high efficiency and low fabrication cost are still the main goal that people pursuit for next‐generation solar cells such as dye‐sensitized solar cells (DSSCs) and organic solar cells (OPVs). Polyoxometalates (POMs), as an environmentally friendly material, are a type of stable, low cost and soluble oxide clusters with desirable features, including highly tunable structural properties, peculiar optoelectronic properties and excellent redox properties. Thus, during the recent years, POMs have been increasingly recognized as important building blocks for DSSCs and OPVs. In this review, the development of various molecular and hybrid materials derived from POMs is discussed with regard to the function in solar cells.     

Enhanced Efficiency of Dye-sensitized Solar Cells Using rGO@TiO2 Nanotube Hybrids

We established a novel strategy for the synthesis of reduced graphene oxide(rGO)@TiO₂ nanotube hybrids using an 18 W UV-assisted photo-catalytic reduction method for utilization as photo-anode of dye-sensitized solar cells(DSSCs). The photo-conversion efficiency of DSSCs was significantly enhanced after the addition of rGO, and in addition, the photo-anode showed decreased internal resistance. Analysis of rGO@TiO₂ hybrids by transmissions scanning electron microscopy(TEM), X-ray diffraction(XRD), Raman spectra, N₂ adsorption and desorption, atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS) demonstrates that the rGO modified TiO₂ nanotubes can increase the short-circuit current and the conversion efficiency of dye-sensitized solar cells. The efficiency is improved by almost two folds as much compared to those of the bare TiO₂ nanotubes.