Solid‐State Photovoltaic Thin Films using TiO2, Organic Dyes,and Layer‐by‐Layer Polyelectrolyte Nanocomposites

We report photovoltaic devices consisting of patterned TiO₂, porphyrin dyes, and layer‐by‐layer (LBL) polyelectrolyte multilayer/oligoethylene glycol dicarboxylic acid (OEGDA) composite films. A composite polyelectrolyte LBL/OEGDA film was fabricated by formation of an alternating multilayer of linear polyethyleneimine (LPEI) and polyacrylic acid (PAA), followed by immersion of the LBL film into an OEGDA aqueous solution. The ionic conductivity attained in this LBL LPEI/PAA and OEGDA composite film was approximately 10^–5 S cm^–1 at room temperature and humidity. Investigations of dye‐sensitized photovoltaic devices constructed with the LBL (LPEI/PAA)/OEGDA composite films, TiO₂, and four types of porphyrin dyes resulted in optimization of the dye molecule and its orientation at the interface with the ionically conductive composite. The photocurrent value of photovoltaic devices constructed with the composite LBL/OEGDA film from illumination of a xenon white light source exhibited a nearly 1.5 times enhancement over the device without OEGDA. This enhancement of the photocurrent was due to the high room‐temperature ionic conductivity of the multilayer composite film. Further marked improvements of the photovoltaic performance were achieved by patterning the TiO₂ electrode using polymer stamping as a template for TiO₂ deposition. The device with patterned TiO₂ electrodes exhibited almost 10 times larger conversion efficiencies than a similar device without patterning.     

Layer‐by‐Layer Synthesis of Thick Mesoporous TiO2 Films with Vertically Oriented Accessible Nanopores and Their Application for Lithium‐Ion Battery Negative Electrodes

TiO₂ films of varying thicknesses (up to ≈1.0 µm) with vertically oriented, accessible 7–9 nm nanopores are synthesized using an evaporation‐induced self‐assembly layer‐by‐layer technique. The hypothesis behind the approach is that epitaxial alignment of hydrophobic blocks of surfactant templates induces a consistent, accessible mesophase orientation across a multilayer film, ultimately leading to continuous, vertically aligned pore channels. Characterization using grazing incidence X‐ray scattering, scanning electron microscopy, and impedance spectroscopy indicates that the pores are oriented vertically even in relatively thick films (up to 1 µm). These films contain a combination of amorphous and nanocrystalline anatase titania of value for electrochemical energy storage. When applied as negative electrodes in lithium‐ion batteries, a capacity of 254 mAh g^?1 is obtained after 200 cycles for a single‐layer TiO₂ film prepared on modified substrate, higher than on unmodified substrate or nonporous TiO₂ film, due to the high accessibility of the vertically oriented channels in the films. Thicker films on modified substrate have increased absolute capacity because of higher mass loading but a reduced specific capacity because of transport limitations. These results suggest that the multilayer epitaxial approach is a viable way to prepare high capacity TiO₂ films with vertically oriented continuous nanopores.     

Selective Determination of Dopamine on a Boron‐Doped Diamond Electrode Modified with Gold Nanoparticle/Polyelectrolyte‐coated Polystyrene Colloids

Negatively charged gold nanoparticles (AuNPs) and a polyelectrolyte (PE) have been assembled alternately on a polystyrene (PS) colloid by a layer‐by‐layer (LBL) self‐assembly technique to form three‐dimensional (Au/PAH)₄/(PSS/PAH)₄ multilayer‐coated PS spheres (Au/PE/PS multilayer spheres). The Au/PE/PS multilayer spheres have been used to modify a boron‐doped diamond (BDD) electrode. Cyclic voltammetry is utilized to investigate the properties of the modified electrode in a 1.0 M KCl solution that contains 5.0 × 10^?3 M K₃Fe(CN)₆, and the result shows a dramatically decreased redox activity compared with the bare BDD electrode. The electrochemical behaviors of dopamine (DA) and ascorbic acid (AA) on the bare and modified BDD electrode are studied. The cyclic voltammetric studies indicate that the negatively charged, three‐dimensional Au/PE/PS multilayer sphere‐modified electrodes show high electrocatalytic activity and promote the oxidation of DA, whereas they inhibit the electrochemical reaction of AA, and can effectively be used to determine DA in the presence of AA with good selectivity. The detection limit of DA is 0.8 × 10^?6 M in a linear range from 5 × 10^?6 to 100 × 10^?6 M in the presence of 1 × 10^?3 M AA.     

Dual‐Function Scattering Layer of Submicrometer‐Sized Mesoporous TiO2 Beads for High‐Efficiency Dye‐Sensitized Solar Cells

Submicrometer‐sized (830 ± 40 nm) mesoporous TiO₂ beads are used to form a scattering layer on top of a transparent, 6‐µm‐thick, nanocrystalline TiO₂ film. According to the Mie theory, the large beads scatter light in the region of 600–800 nm. In addition, the mesoporous structure offers a high surface area, 89.1 m² g^?1, which allows high dye loading. The dual functions of light scattering and electrode participation make the mesoporous TiO₂ beads superior candidates for the scattering layer in dye‐sensitized solar cells. A high efficiency of 8.84% was achieved with the mesoporous beads as a scattering layer, compared with an efficiency of 7.87% for the electrode with the scattering layer of 400‐nm TiO₂ of similar thickness.     

Enhanced Performance of I2‐Free Solid‐State Dye‐Sensitized Solar Cells with Conductive Polymer up to 6.8%

An iodine‐free solid‐state dye‐sensitized solar cell (ssDSSC) is reported here, with 6.8% energy conversion efficiency—one of the highest yet reported for N719 dye—as a result of enhanced light harvesting from the increased transmittance of an organized mesoporous TiO₂ interfacial layer and the good hole conductivity of the solid‐state‐polymerized material. The organized mesoporous TiO₂ (OM‐TiO₂) interfacial layer is prepared on large‐area substrates by a sol‐gel process, and is confirmed by scanning electron microscopy (SEM) and grazing incidence small‐angle X‐ray scattering (GISAXS). A 550‐nm‐thick OM‐TiO₂ film coated on fluorine‐doped tin oxide (FTO) glass is highly transparent, resulting in transmittance increases of 8 and 4% compared to those of the bare FTO and conventional compact TiO₂ film on FTO, respectively. The high cell performance is achieved through careful control of the electrode/hole transport material (HTM) and nanocrystalline TiO₂/conductive glass interfaces, which affect the interfacial resistance of the cell. Furthermore, the transparent OM‐TiO₂ film, with its high porosity and good connectivity, exhibits improved cell performance due to increased transmittance in the visible light region, decreased interfacial resistance ( Ω ), and enhanced electron lifetime ( τ ). The cell performance also depends on the conductivity of HTMs, which indicates that both highly conductive HTM and the transparent OM‐TiO₂ film interface are crucial for obtaining high‐energy conversion efficiencies in I₂‐free ssDSSCs.     

Nitridation and Layered Assembly of Hollow TiO2 Shells for Electrochemical Energy Storage

The nitridation of hollow TiO₂ nanoshells and their layered assembly into electrodes for electrochemical energy storage are reported. The nitridated hollow shells are prepared by annealing TiO₂ shells, produced initially using a sol–gel process, under an NH₃ environment at different temperatures ranging from 700 to 900 °C, then assembled to form a robust monolayer film on a water surface through a quick and simple assembly process without any surface modification to the samples. This approach facilitates supercapacitor cell design by simplifying the electrochemical electrode structure by removing the need to use any organic binder or carbon‐based conducting materials. The areal capacitance of the as‐prepared electrode is observed to be ≈180 times greater than that of a bare TiO₂ electrode, mainly due to the enhanced electrical conductivity of the TiN phase produced through the nitridation process. Furthermore, the electrochemical capacitance can be enhanced linearly by constructing an electrode with multilayered shell films through a repeated transfer process (0.8 to 7.1 mF cm^–2, from one monolayer to 9 layers). Additionally, the high electrical conductivity of the shell film makes it an excellent scaffold for supporting other psuedocapacitive materials (e.g., MnO₂), producing composite electrodes with a specific capacitance of 743.9 F g^–1 at a scan rate of 10 mV s^–1 (based on the mass of MnO₂) and a good cyclic stability up to 1000 cycles.     

Layer‐By‐Layer Dendritic Growth of Hyperbranched Thin Films for Surface Sol–Gel Syntheses of Conformal,Functional, Nanocrystalline Oxide Coatings on Complex 3D (Bio)silica Templates

Here, a straightforward and general method for the rapid dendritic amplification of accessible surface functional groups on hydroxylated surfaces is described, with focus on its application to 3D biomineral surfaces. Reaction of hydroxyl‐bearing silica surfaces with an aminosilane, followed by alternating exposure to a dipentaerythritol‐derived polyacrylate solution and a polyamine solution, allows the rapid, layer‐by‐layer (LBL) build‐up of hyperbranched polyamine/polyacrylate thin films. Characterization of such LBL‐grown thin films by AFM, ellipsometry, XPS, and contact angle analyses reveals a stepwise and spatially homogeneous increase in film thickness with the number of applied layers. UV–Vis absorption analyses after fluorescein isothiocyanate labeling indicate that significant amine amplification is achieved after the deposition of only 2 layers with saturation achieved after 3–5 layers. Use of this thin‐film surface amplification technique for hydroxyl‐enrichment of biosilica templates facilitates the conformal surface sol–gel deposition of iron oxide that, upon controlled thermal treatment, is converted into a nanocrystalline (～9.5 nm) magnetite (Fe₃O₄) coating. The specific adsorption of arsenic onto such magnetite‐coated frustules from flowing, arsenic‐bearing aqueous solutions is significantly higher than for commercial magnetite nanoparticles (≤50 nm in diameter).     

All‐Solution‐Processed Indium‐Free Transparent Composite Electrodes based on Ag Nanowire and Metal Oxide for Thin‐Film Solar Cells

Fully solution‐processed Al‐doped ZnO/silver nanowire (AgNW)/Al‐doped ZnO/ZnO multi‐stacked composite electrodes are introduced as a transparent, conductive window layer for thin‐film solar cells. Unlike conventional sol–gel synthetic pathways, a newly developed combustion reaction‐based sol–gel chemical approach allows dense and uniform composite electrodes at temperatures as low as 200 °C. The resulting composite layer exhibits high transmittance (93.4% at 550 nm) and low sheet resistance (11.3 Ω sq^‐1), which are far superior to those of other solution‐processed transparent electrodes and are comparable to their sputtered counterparts. Conductive atomic force microscopy reveals that the multi‐stacked metal‐oxide layers embedded with the AgNWs enhance the photocarrier collection efficiency by broadening the lateral conduction range. This as‐developed composite electrode is successfully applied in Cu(In_1‐x,Ga_x)S₂ (CIGS) thin‐film solar cells and exhibits a power conversion efficiency of 11.03%. The fully solution‐processed indium‐free composite films demonstrate not only good performance as transparent electrodes but also the potential for applications in various optoelectronic and photovoltaic devices as a cost‐effective and sustainable alternative electrode.     

Highly Stable Graphene‐Based Multilayer Films Immobilized via Covalent Bonds and Their Applications in Organic Field‐Effect Transistors

Highly stable graphene oxide (GO)‐based multilayered ultrathin films can be covalently immobilized on solid supports through a covalent‐based method. It is demonstrated that when (3‐aminopropyl) trimethoxysilane (APTMS), which works as a covalent cross‐linking agent, and GO nanosheets are assembled in an layer‐by‐layer (LBL) manner, GO nanosheets can be covalently grafted on the solid substrate successfully to produce uniform multilayered (APTMS/GO)N films over large‐area surfaces. Compared with conventional noncovalent LBL films constructed by electrostatic interactions, those assembled using this covalent‐based method display much higher stability and reproducibility. Upon thermal annealing‐induced reduction of the covalent (APTMS/GO)N films, the obtained reduced GO (RGO) films, (APTMS/RGO)N, preserve their basic structural characteristics. It is also shown that the as‐prepared covalent (APTMS/RGO)N multilayer films can be used as highly stable source/drain electrodes in organic field‐effect transistors (OFETs). When the number of bilayers of the (APTMS/RGO)N film exceeds 2 (ca. 2.7 nm), the OFETs based on (APTMS/RGO)N electrodes display much better electrical performance than devices based on 40 nm Au electrodes. The covalent protocol proposed may open up new opportunities for the construction of graphene‐based ultrathin films with excellent stability and reproducibility, which are desired for practical applications that require withstanding of multistep post‐production processes.     

Enhancing the Performance of Solid‐State Dye‐Sensitized Solar Cells Using a Mesoporous Interfacial Titania Layer with a Bragg Stack

High efficiency dye‐sensitized solar cells (DSSCs) are fabricated with a heterostructured photoanode that consists of a 500‐nm‐thick organized mesoporous TiO₂ (om‐TiO₂) interfacial layer (IF layer), a 7 or 10‐μm thick nanocrystalline TiO₂ layer (NC layer), and a 2‐μm‐thick mesoporous Bragg stack (meso‐BS layer) as the bottom, middle and top layers, respectively. An om‐TiO₂ layer with a high porosity, transmittance, and interconnectivity is prepared via a sol‐gel process, in which a poly(vinyl chloride)‐g‐poly(oxyethylene methacrylate) (PVC‐g‐POEM) graft copolymer is used as a structure‐directing agent. The meso‐BS layer with large pores is prepared via alternating deposition of om‐TiO₂ and colloidal SiO₂ (col‐SiO₂) layers. Structure and optical properties (refractive index) of the om‐TiO₂ and meso‐BS layers are studied and the morphology of the heterostructured photoanode is characterized. DSSCs fabricated with the heterostructured IF/NC/BS photoanode and combined with a polymerized ionic liquid (PIL) exhibit an energy conversion efficiencies of 6.6% at 100 mW/cm², one of the highest reported for solid‐state DSSCs and much larger than cells prepared with only a IF/NC layer (6.0%) or a NC layer (4.5%). Improvements in energy conversion efficiency are attributed to the combination of improved light harvesting, decreased resistance at the electrode/electrolyte interface, and excellent electrolyte infiltration.     

Optical and Electrical Properties of TixSi1‐xOy Films

Ti_xSi_1xO_y (TSO) thin films are fabricated using plasma‐enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub‐cycle ratio of TiO₂ and SiO₂. The refractive indices of SiO₂ and TiO₂ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current‐voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.     

A Decaheme Cytochrome as a Molecular Electron Conduit in Dye‐Sensitized Photoanodes

In nature, charge recombination in light‐harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye‐sensitized TiO₂ nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR‐1, where the 10 hemes of MtrC form a ≈7‐nm‐long molecular wire between the TiO₂ and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra‐flat gold electrode, followed by the adsorption of approximately 7 nm TiO₂ nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step‐by‐step construction of the MtrC/TiO₂ system is monitored with (photo)electrochemistry, quartz‐crystal microbalance with dissipation (QCM‐D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO₂ nanocrystals to the surface via the MtrC conduit. In other words, in these TiO₂/MtrC hybrid photodiodes, MtrC traps the conduction‐band electrons from TiO₂ before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.     

Surface Control of Planarization Layer on Embossed Glass for Light Extraction in OLEDs

We developed a highly refractive index planarization layer showing a very smooth surface for organic light‐emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano‐structure and highly refractive index planarization layers. White OLEDs act as an internal out‐coupling layer. We used a spin‐coating method and two types of TiO₂ solutions for a planarization of the embossed nano‐structure on a glass substrate. The first TiO₂ solution was TiO₂ sol, which consists of TiO₂ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of TiO₂. The surface roughness (R_a) and refractive index of the TiO₂ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J–V characteristics of the OLED including the embossed nano‐structure and the TiO₂ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.     

High K Capacitors and OFET Gate Dielectrics from Self‐Assembled BaTiO3 and (Ba,Sr)TiO3 Nanocrystals in the Superparaelectric Limit

Nanodielectrics is an emerging field with applications in capacitors, gate dielectrics, energy storage, alternatives to Li‐ion batteries, and frequency modulation in communications devices. Self‐assembly of high k dielectric nanoparticles is a highly attractive means to produce nanostructured films with improved performance—namely dielectric tunability, low leakage, and low loss—as a function of size, composition, and structure. One of the major challenges is conversion of the nanoparticle building block into a reliable thin film device at conditions consistent with integrated device manufacturing or plastic electronics. Here, the development of BaTiO₃ and (Ba,Sr)TiO₃ superparaelectric uniform nanocrystal (8–12 nm) films prepared at room temperature by evaporative driven assembly with no annealing step is reported. Thin film inorganic and polymer composite capacitors show dielectric constants in the tunable range of 10–30, dependent on composition, and are confirmed to be superparaelectric. Organic thin film transistor (TFT) devices on flexible substrates demonstrate the readiness of nanoparticle‐assembled films as gate dielectrics in device fabrication.     

Design of conduction band structure of TiO2 electrode using Nb doping for highly efficient dye‐sensitized solar cells

A barrier layer of undoped TiO₂ was deposited on the Nb‐doped TiO₂ electrode to suppress the recombination at the Nb‐doped TiO₂/dye–electrolyte interface for highly efficient dye‐sensitized solar cells (DSCs). The Nb content in TiO₂ was varied in a range of 0.7–3.5 mol% to modify the TiO₂ energy‐band structure. Nb‐doped TiO₂/dye interfaces were characterized by a combination of ultraviolet photoemission spectroscopy and optical absorption spectroscopy measurements, allowing the determination of the conduction band minimum (CBM) of the TiO₂ electrode and the lowest unoccupied molecular orbital of the N719 dye. The lowering of TiO₂ CBM by Nb doping induced the increase in short‐circuit current of DSCs. However, open‐circuit voltage and fill factor are decreased, and this result was ascribed to the enhanced recombination at the Nb‐doped TiO₂/dye–electrolyte interface. The effect of doping on charge transport in DSCs was analyzed using electrochemical impedance spectroscopy. We have shown that by introducing of TiO₂ barrier layer, the Nb doping content, which results in DSC highest efficiency, can be increased because of the suppression of the dopant‐induced recombination. The energy conversion efficiency of the solar cells increased from 7.8% to 9.0% when undoped TiO₂ electrode is replaced with electrode doped with 2.7 mol% of Nb because of the improvement of the electron injection and collection efficiencies. The correlation between the electronic structure of the TiO₂ electrode, charge transfer characteristics, and photovoltaic parameters of DSCs is discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Room‐Temperature Synthesis of Porous Nanoparticulate TiO2 Films for Flexible Dye‐Sensitized Solar Cells

A novel room‐temperature method for the preparation of porous TiO₂ films with high performance in dye‐sensitized solar cells (DSSCs) has been developed. In this method a small amount of Ti^IV tetraisopropoxide (TTIP) is added to an ethanolic paste of TiO₂ nanoparticles, where it hydrolyzes in situ and connects the TiO₂ particles to form a homogenous and mechanically stable film of up to 10 μm thickness without crack formation. Residual organics originating from the TTIP were removed by UV–ozone treatment of the films, leading to a remarkable improvement of the cell efficiency. Intensity‐modulated photocurrent/voltage spectroscopy (IMPS/IMVS) showed that the main effect of the UV–ozone treatment is to suppress the recombination of photogenerated electrons, thereby extending their lifetime. The efficiency was further increased by preheating the TiO₂ nanoparticles before the paste preparation to remove contaminants originating from the preparation process of the particles. Solar‐to‐electric energy conversion efficiencies of 4.00 and 3.27 % have been achieved for cells with conductive glass and plastic film substrates, respectively, under illumination with AM 1.5 (100 mW cm^–2) simulated sunlight.     

PbS and CdS Quantum Dot‐Sensitized Solid‐State Solar Cells: “Old Concepts,New Results”

Lead sulfide (PbS) and cadmium sulfide (CdS) quantum dots (QDs) are prepared over mesoporous TiO₂ films by a successive ionic layer adsorption and reaction (SILAR) process. These QDs are exploited as a sensitizer in solid‐state solar cells with 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) as a hole conductor. High‐resolution transmission electron microscopy (TEM) images reveal that PbS QDs of around 3 nm in size are distributed homogeneously over the TiO₂ surface and are well separated from each other if prepared under common SILAR deposition conditions. The pore size of the TiO₂ films and the deposition medium are found to be very critical in determining the overall performance of the solid‐state QD cells. By incorporating promising inorganic QDs (PbS) and an organic hole conductor spiro‐OMeTAD into the solid‐state cells, it is possible to attain an efficiency of over 1% for PbS‐sensitized solid‐state cells after some optimizations. The optimized deposition cycle of the SILAR process for PbS QDs has also been confirmed by transient spectroscopic studies on the hole generation of spiro‐OMeTAD. In addition, it is established that the PbS QD layer plays a role in mediating the interfacial recombination between the spiro‐OMeTAD⁺ cation and the TiO₂ conduction band electron, and that the lifetime of these species can change by around 2 orders of magnitude by varying the number of SILAR cycles used. When a near infrared (NIR)‐absorbing zinc carboxyphthalocyanine dye (TT1) is added on top of the PbS‐sensitized electrode to obtain a panchromatic response, two signals from each component are observed, which results in an improved efficiency. In particular, when a CdS‐sensitized electrode is first prepared, and then co‐sensitized with a squarine dye (SQ1), the resulting color change is clearly an addition of each component and the overall efficiencies are also added in a more synergistic way than those in PbS/TT1‐modified cells because of favorable charge‐transfer energetics.     

Fabrication of screen‐printing pastes from TiO2 powders for dye‐sensitised solar cells

A preparation technique of TiO₂ screen‐printing pastes from commercially‐available powders has been disclosed in order to fabricate the nanocrystalline layers without cracking and peeling‐off over 17 µm thickness for the photoactive electrodes of the dye‐sensitised solar cells. A conversion efficiency of 8·7% was obtained by using a single‐layer of a semi‐transparent‐TiO₂ film. A conversion efficiency of 9·2% was obtained by using double‐layers composed of transparent and light‐scattering TiO₂ films for a photon‐trapping system. Copyright © 2007 John Wiley & Sons, Ltd.     

Fabrication of Superstrong Ultrathin Free‐Standing Single‐Walled Carbon Nanotube Films via a Wet Process

A one‐pot and readily practical approach is described for the preparation of superstrong, ultrathin, free‐standing single‐walled carbon nanotube (SWNT) films. The SWNT films, with controlled thicknesses of tens to hundreds of nanometers, are prepared from commonly commercialized SWNTs via a wet process. The SWNTs could be easily transferred onto any substrates after self‐releasing from filter membranes without further treatment. The obtained films exhibit excellent performances with sheet resistance of 223 Ω sq^?1 and a transparency of 90% at 550 nm was obtained. Most important is that the as‐prepared free‐standing SWNT ultrathin films showed extremely high tensile strength up to 850 MPa for only about a 20‐nm thick film, which has great significance for practical applications, for example, as flexible electrode materials. The SWNT film is used to construct a capacitive touch‐screen prototype, which has a highly sensitive and quick signal touch response.     

A Thiophene‐Based Anchoring Ligand and Its Heteroleptic Ru(II)‐Complex for Efficient Thin‐Film Dye‐Sensitized Solar Cells

A novel heteroleptic Ru^II complex (BTC‐2) employing 5,5′‐(2,2′‐bipyridine‐4,4′‐diyl)‐bis(thiophene‐2‐carboxylic acid) (BTC) as the anchoring group and 4,4′‐ dinonyl‐2,2′‐bipiridyl and two thiocyanates as ligands is prepared. The photovoltaic performance and device stability achieved with this sensitizer are compared to those of the Z‐907 dye, which lacks the thiophene moieties. For thin mesoporous TiO₂ films, the devices with BTC‐2 achieve higher power conversion efficiencies than those of Z‐907 but with a double‐layer thicker film the device performance is similar. Using a volatile electrolyte and a double layer 7 + 5 μm mesoporous TiO₂ film, BTC‐2 achieves a solar‐to‐electricity conversion efficiency of 9.1% under standard global AM 1.5 sunlight. Using this sensitizer in combination with a low volatile electrolyte, a photovoltaic efficiency of 8.3% is obtained under standard global AM 1.5 sunlight. These devices show excellent stability when subjected to light soaking at 60 °C for 1000 h. Electrochemical impedance spectroscopy and transient photovoltage decay measurements are performed to help understand the changes in the photovoltaic parameters during the aging process. In solid state dye‐sensitized solar cells (DSSCs) using an organic hole‐transporting material (spiro‐MeOTAD, 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene), the BTC‐2 sensitizer exhibits an overall power conversion efficiency of 3.6% under AM 1.5 solar (100 mW cm^?2) irradiation.