Application of carbon materials as counter electrodes of dye-sensitized solar cells

Hard carbon spherule (HCS) has been investigated as a counter electrode for dye-sensitized solar cells. The overall conversion efficiency of the cell reached 5.7%, which is comparable to 6.5% of the counter electrode of platinum-sputtered fluorine-doped tin oxide used in Grätzel-type solar cells under the same experimental condition. It is found that the photovoltaic performance was strongly affected by the specific surface areas of the carbon materials.     

TiO2/ZnO薄膜电极中光生电子的传输及其在太阳电池中的应用

制备了TiO2纳米颗粒和ZnO纳米棒混合的多孔薄膜电极, 利用瞬态光电压技术研究了染料敏化TiO2/ZnO薄膜中光生载流子的传输特性. 实验结果表明, ZnO纳米棒增加了薄膜中自由电子扩散速率, 减小了复合几率, 改善了能量转换效率.     

Preparation of nanoporous MgO-coated TiO2 nanoparticles and their application to the electrode of dye-sensitized solar cells

Sol-gel-derived Mg(OH)(2) gel was coated onto TiO(2) nanoparticles, and the subsequent thermal topotactic decomposition of the gel formed a highly nanoporous MgO crystalline coating. The specific surface area of the electrode that was prepared from the core-shell-structured TiO(2) nanoparticles significantly increased compared with that of the uncoated TiO(2) electrode. The increase in the specific surface area of the MgO-coated TiO(2) electrode was attributed to the highly nanoporous MgO coating layer that resulted from the topotactic reaction. Dye adsorption behavior and solar cell performance were significantly enhanced by employing the MgO-coated TiO(2) electrode. Optimized coating of a MgO layer on TiO(2) nanoparticles enhanced the energy conversion efficiency as much as 45% compared to that of the uncoated TiO(2) electrode. This indicates that controlling the extrinsic parameters such as the specific surface area is very important to improve the energy conversion efficiency of TiO(2)-based solar cells.     

Large size, high efficiency fiber-shaped dye-sensitized solar cells

A high-efficiency dye-sensitized solar cell prototype has been designed and fabricated, in which the working electrode and counter electrode are in direct contact and singly twisted. The cell is sealed in a capillary. In this solar cell configuration, the area ratio between the counter and working electrode is extremely low which allows the independent adjustment of electrolyte volume and the distance between counter electrode and photo-anode. Also it is more easily sealed compared to planar solar cell. The effects of TiO(2) film thickness, twisted pitch of counter electrode and length of device have been investigated. Our results indicate that this novel configuration has demonstrated excellent modularization function, three dimensional light harvesting capacities and the relative independence of incident light angles due to the symmetry structure. The power conversion efficiency of one cell of 9.5 cm in length can reach up to 5.41% at standard test condition (100 mW cm(-2)) and the power output may double under intense diffuse illumination. As far as we know, this is the longest and most efficient fiber-shaped dye-sensitized solar cell consisting of liquid electrolyte. The longer the fiber-shaped solar cell is, the more suitable it is for woven solar power textile if it is encapsulated in transparent flexible plastic capillary.     

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。     

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TiO_2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。     

掺钠钼电极在硒化铜铟镓(CIGS)太阳能薄膜电池应用

适量钠元素对铜铟镓硒薄膜生长具有促进作用,本文主要研究了掺钠钼电极特性及其对铜铟镓硒薄膜太阳能电池性能的影响。利用磁控溅射方法制备不同厚度的钼钠/钼(Mo Na/Mo)薄膜作为背电极,并在(Mo Na/Mo)薄膜电极上蒸镀铜铟镓硒(CIGS)薄膜,并利用单质硒源硒化处理后制备CIGS薄膜电池。SEM和XRD结果表明采用三层叠层Mo/Mo/Mo Na薄膜做电极的Mo Na容易被氧化,电阻率增加,采用四层叠层Mo/Mo/Mo Na/Mo薄膜电极方式有效降低电阻率,阻止Mo Na被氧化,CIGS晶粒较大且致密。在同一条件下,在不同Mo Na/Mo厚度电极上制备CIGS薄膜电池,80 nm Mo Na厚度上的CIGS薄膜电池效率达6.54%。     

Enhancement of the efficiency of dye-sensitized solar cell with multi-wall carbon nanotubes/polythiophene composite counter electrodes prepared by electrodeposition

For the purpose of increasing the energy conversion efficiency of dye-sensitized solar cells (DSSCs), multi-wall carbon nanotube (MWCNT)/polythiophene (PTh) composite film counter electrode has been fabricated by electrophoresis and cyclic voltammetry (CV) in sequence. The morphology and chemical structure have been characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), and Raman spectroscopy respectively. The overall energy conversion efficiency of the DSSC employing the MWCNT/PTh composite film has reached 4.72%, which is close to that of the DSSC with a platinum (Pt) counter electrode (5.68%). Compared with a standard DSSC with MWCNT counter electrode whose efficiency is 2.68%, the energy conversion efficiency has been increased by 76.12% for the DSSC with MWCNT/PTh counter electrode. These results indicate that the composite film with high conductivity, high active surface area, and good catalytic properties for I₃⁻ reduction can potentially be used as the counter electrode in a high-performance DSSC.     

Rh-doped SrTiO3 photocatalyst electrode showing cathodic photocurrent for water splitting under visible-light irradiation

A Rh-doped SrTiO(3) (SrTiO(3):Rh) photocatalyst electrode that was readily prepared by pasting SrTiO(3):Rh powder onto a transparent indium tin oxide electrode gave a cathodic photocurrent under visible-light irradiation (λ > 420 nm), indicating that the SrTiO(3):Rh photocatalyst electrode possessed p-type semiconductor character. The cathodic photocurrent increased with an increase in the amount of doped Rh up to 7 atom %. The incident-photon-to-current efficiency at 420 nm was 0.18% under an applied potential of -0.7 V vs Ag/AgCl for the SrTiO(3):Rh(7 atom %) photocatalyst electrode. The photocurrent was confirmed to be due to water splitting by analyzing the evolved H(2) and O(2). The water splitting proceeded with the application of an external bias smaller than 1.23 V versus a Pt counter electrode under visible-light irradiation and also using a solar simulator, suggesting that solar energy conversion should be possible with the present photoelectrochemical water splitting.     

Squarylium Cyanine Dyes for Photoelectric Conversion

Asanimportantclassoffunctionalmaterials,squaryliumcyaninedyespossessmanyexcellentpropertiessuchasstablestructures,outstandingphotoconductivityaswellassmallthermalconductivity,andexhibitintenseandsharpabsorptionbandsinthevisibleandnearinfraredregionwithhighlightharvestingcapacity,whichopenupextensiveapplicationsinthevariousfieldsl-3.Inthispaper,twosymmetricalsquaryliumindocyanineswiththeintroductionofhydroxyethylandsulfopropylgroupsontheheterocyclicnitrogenweresynthesizedandcharacterizedbyUV,I…     

High dispersion Pt nanoparticles using mesoporous carbon support for enhancing conversion efficiency of dye-sensitized solar cells

<正>Mesoporous carbon(MC) with surface area of 380 m~2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.     

Highly Efficiency p-Type Dye Sensitized Solar Cells Based on Polygonal Star-morphology Cu2O Material of Photocathodes

Cuprous oxide（Cu2O）,as an important p-type semiconductor,has been widely investigated due to its high electron transmission and facile preparation.However,the electrode made of only Cu2O has been rarely investigated.In order to demonstrate the possibility that material Cu2O can be applied to the electrode of p-type dye sensitized solar cells（DSSCs）,the photo-electrodes made of prepared Cu2O powder and commercial Cu2O particles have been fabricated.The results show that the electrode based on as-prepared Cu2O（Cu2O-2） powder exhibits higher performance than that based on commercial Cu2O（Cu2O-1） particle.The device based on Cu2O-2 electrode reaches into an open-circuit voltage of 0.71 V,a short-circuit current density of 1.3 mA/cm^2,a fill factor（FF） of 46%,and a conversion efficiency of 0.42% measured under AM 1.5G（100 mW/cm^2） illumination.The enhancement performance of Cu2O-2 is attributed to the high dye adsorption of Cu2O-2 compared with that of Cu2O-1.To the best of our knowledge,this is the highest conversion efficiency value reported for solar cells based on Cu2O-DSSC.This work provides that Cu2O is also a candidate for constructing the electrode of p-type dye sensitized solar cells.     

碳基钙钛矿太阳能电池的研究进展

由于具有成本低、工艺简单等优点,有机-无机杂化太阳能电池(PSCs)的研究和发展受到了广泛的关注,光电转换效率也快速提升到与传统晶体硅太阳能电池相当的水平。 然而,PSCs稳定性差的问题严重限制了其商业化。 在各种PSCs中,基于碳电极的无空穴传输层器件(C-PSCs)去除了影响稳定性的有机空穴传输层和金属电极,使得器件稳定性得到了明显的提高,是最具有应用前景的电池器件之一。 自从2013年首次报道以来,C-PSCs的各方面研究取得了很大的进展,效率也从最初的6.6%提高到现在的15.9%。 本综述将系统地介绍C-PSCs的最新研究进展,包括器件结构和工作原理、各部分研究进展(电子传输层、钙钛矿薄膜和碳电极),以及存在的问题和解决方案。     

Self-Assembled Graphene/MWCNT Bilayers as Platinum-Free Counter Electrode in Dye-Sensitized Solar Cells

We describe the preparation and properties of bilayers of graphene- and multi-walled carbon nanotubes (MWCNTs) as an alternative to conventionally used platinum-based counter electrode for dye-sensitized solar cells (DSSC). The counter electrodes were prepared by a simple and easy-to-implement double self-assembly process. The preparation allows for controlling the surface roughness of electrode in a layer-by-layer deposition. Annealing under N₂ atmosphere improves the electrode's conductivity and the catalytic activity of graphene and MWCNTs to reduce the I₃⁻ species within the electrolyte of the DSSC. The performance of different counter-electrodes is compared for ZnO photoanode-based DSSCs. Bilayer electrodes show higher power conversion efficiencies than monolayer graphene electrodes or monolayer MWCNTs electrodes. The bilayer graphene (bottom)/MWCNTs (top) counter electrode-based DSSC exhibits a maximum power conversion efficiency of 4.1 % exceeding the efficiency of a reference DSSC with a thin film platinum counter electrode (efficiency of 3.4 %). In addition, the double self-assembled counter electrodes are mechanically stable, which enables their recycling for DSSCs fabrication without significant loss of the solar cell performance.     

Integrating Perovskite Solar Cells into a Flexible Fiber

Perovskite solar cells have triggered a rapid development of new photovoltaic devices because of high energy conversion efficiencies and their all‐solid‐state structures. To this end, they are particularly useful for various wearable and portable electronic devices. Perovskite solar cells with a flexible fiber structure were now prepared for the first time by continuously winding an aligned multiwalled carbon nanotube sheet electrode onto a fiber electrode; photoactive perovskite materials were incorporated in between them through a solution process. The fiber‐shaped perovskite solar cell exhibits an energy conversion efficiency of 3.3 %, which remained stable on bending. The perovskite solar cell fibers may be woven into electronic textiles for large‐scale application by well‐developed textile technologies.     

基于网状铂电极的新型柔性染料敏化太阳能电池

柔性染料敏化太阳能电池（DSSCs）作为一种新型的化学太阳能电池,因其精简的封装工艺、较低廉的价格、高的化学稳定性以及可弯折等优点而备受关注. 本文介绍了一种新型的柔性DSSC的制备,其光阳极为高度有序的氧化锌（ZnO）纳米线阵列,对电极为柔性、导电、透明的网状铂(Pt networks)电极. 相对于传统的铂对电极而言,这种Pt networks对电极不仅具有优异的导电能力,还展现了极好的透光性（方阻~ 100 Ω•sq^-1,~80%透光率）和催化性能,此外,Pt networks电极可构筑于任意弯曲的衬底,具有优异的机械耐弯折性能. 在ZnO纳米线阵列的DSSCs的应用中,基于Pt networks膜的柔性DSSC的转化效率比铂纳米丝阵列 (Pt nanofiber arrays, Pt NFs）膜高出了32%.     

Low Sheet Resistance Counter Electrode in Dye-sensitized Solar Cell

In order to search for the high efficiency and low sheet resistance counter electrode indye-sensitized solar cell, we used Ti plate as the conducting substrate to prepare the counterelectrode by thermal decomposition of H2PtC16. Ti plate counter electrode shows low sheetresistance, good reflecting performance and matching kinetics. The dye-sensitized solar cell with theTi plate counter electrode shows better photovoltaic performance than that of the cell with thefluorine-doped tin oxide-coated glass counter electrode.     

Composite Electrode SnO2／TiO2 for Dye-Sensitized Solar Cells

Composite nanoporous electrode SnO2/TiO2 was fabricated for the dye sensitized solar cell (DSSC) with N3 (Cis-Ru). After introducing of TiO2, the open-circuit photovoltage (Voc) was higher than that of the pure SnO2 electrode, while short-circuit photocurrent (Isc) was varied with the ratio of the TiO2. Appropriate content of the TiO2 can be beneficial to the efficiency of the solar cell, and it gives negative impact on the composite electrode when the content of TiO2 is higher.     

Photoelectrochemical and Photovoltaic Characteristics of Amorphous‐Silicon‐Based Tandem Cells as Photocathodes for Water Splitting

In this study amorphous silicon tandem solar cells are successfully utilized as photoelectrodes in a photoelectrochemical cell for water electrolysis. The tandem cells are modified with various amounts of platinum and are combined with a ruthenium oxide counter electrode. In a two‐electrode arrangement this system is capable of splitting water without external bias with a short‐circuit current of 4.50 mA cm^?2. On the assumption that no faradaic losses occur, a solar‐to‐hydrogen efficiency of 5.54 % is achieved. In order to identify the relevant loss processes, additional three‐electrode measurements were performed for each involved half‐cell.     

All-carbon electrode-based fiber-shaped dye-sensitized solar cells

A novel fiber-shaped dye-sensitized solar cell (DSSC) based on an all-carbon electrode is presented, where low-cost, highly-stable, and biocompatible carbon materials are applied to both the photoanode and the counter electrode. The fibrous carbon-based photoanode has a core-shell structure, with carbon fiber core used as conductive substrate to collect carriers and sensitized porous TiO(2) film as shell to harvest light effectively. The highly catalytic all-carbon counter electrode is made from ink carbon coatings and carbon fiber substrate. Results show that the open circuit voltage can be largely improved through engineering at the carbon fiber/TiO(2) interface. An optimized diameter of the photoanode results in an efficiency of 1.9%. It is the first demonstration of efficient DSSCs based on all-carbon electrodes, and the devices are totally free from TCOs or any other expensive electrode materials. Also, this type of solar cell is significant in obtaining bio-friendly all-carbon photovoltaics suitable for large-scale production.