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A tandem solid-state dye-sensitized solar cell (SSDSC) without color distortion for potential photovoltaic window applications is reported. The bifacial tandem SSDSC with two spectrally complementary sensitizers using parallel-connection is realized, which leads to non-color distortion. The Commission Internationale de l'Eclairage (CIE) chromaticity diagram is applied to verify the extent of color distortion. At this circumstance, the photovoltaic performance for the tandem SSDSC with a power conversion efficiency of 3.3% was achieved under AM 1.5G, 100 mW/cm2 illumination. The overall efficiency in the tandem architecture outperformed each individual cell. Our results demonstrate the feasibility for visible light transmission, non-color distortion, power-generating windows for application in building-integrated photovoltaics (BIPV). Moreover, this tandem SSDSC architecture has potential for the integration into window curtains application due to its flexible characteristics. With further extension of the absorber spectrum into the IR region, a better solid-state tandem DSC is expected.

In this study, we propose a novel concept of extending the lifetime of dye-sensitized solar cells (DSCs) and reducing the costs of re-conditioning DSCs by recycling the FTO/TiO2 substrates. The photovoltaic performances of DSCs using substrates with various cycles of dye uptake and rinse off history are tested. The results show that dye adsorption and Voc are significantly increased under multiple dye adsorption/desorption process and resulted in the improvement of power conversion efficiency. Moreover, the dyeing kinetics is faster after multiple recycling processes, which is favorable for the industrial application. With surface analysis and charge transport characteristics, we also demonstrate the optimal functionality of TiO2/dye interface for the improved Voc and efficiency. The results confirm that the improved performances are due to increased dye loading and dense packing of dye molecules. Our results are beneficial for the understanding on the extension of DSCs lifetime after long-term operation in the application of DSC modules. This approach may also be applied in the replacement of newly synthesized photosensitizes to the active cells.

A diffusive solar cell window comprises a diffusion plate with TiO2nanoparticles sandwiched between two glass layers. It is a simple, inexpensive, easy-to-made, and highly reliable transparent solar energy module. To improve its power generation efficiency as well as maintain indoor natural lighting, we examined the scattering mechanism in the diffusion plate with TiO2nanoparticles within a diffusive solar cell window by Mie scattering simulations. In this work, a multiwavelength ASAP ray tracing model for a diffusive solar cell window with acceptable accuracy was developed to investigate the influence of the diffusion plate design parameter, mainly concentration of a diffusion plate with determined particle size distribution, on power generation efficiency and color shift of transmitted sun light. A concept of “effective average radius” was proposed to account for the equivalent scattering effect of a size distribution of quasispherical particles. Simulation results demonstrated that both the transmitted light and its correlated color temperature decreased as the concentration increased for a large-size diffusive solar cell window. However, there existed a maximum power generation efficiency at around 160 ppm concentration. The optimal design for a large-size diffusion plate inside a diffusive solar cell window by taking indoor lighting into account was suggested based on the simulation results.

This study reports the fabrication of efficient deep blue-emissive polymer light-emitting diodes (PLEDs), incorporating a polyfluorene derivative of nonsymmetric and bulky aromatic groups at C-9 position as the light-emissive layer. Another poly(fluorene- co -triphenylamine) (PFO-TPA) derivative of the highest occupied molecular orbital level, −5.3 eV, is used as the hole-injection and -transport layer in the anode part. The thermally crosslinking of styryl groups in PFO-TPA inhibits the solvation of an interlayer in constructing the multilayer device architecture of PLEDs. While applying a cesium carbonate (Cs 2 CO 3 )/Aluminum (Al) cathode rather than Calcium (Ca)/Al, the device has the superior performance (i.e. one order of magnitude higher). Experimental results indicate that the interfacial reactions at the polymer/Ca junction, as characterized in this study, significantly degrade the luminescence properties and the device performance. Moreover, Cs 2 CO 3 /Al is a highly favorable cathode in fabricating polyflourene-based PLEDs. The device of the optimal configuration has a decent deep blue emission centered at 430–450 nm of the Commission Internationale de l’Eclairage chromaticity coordinates, (0.15, 0.14), with a maximum brightness of 35054.2 cd/m 2 and luminous efficiency of 14.0 cd/A (at 2975.0 cd/m 2 ).

A diffusive solar cell window was designed and fabricated with uniformly distributed nanocomposite particles in a light diffusive plate that was sandwiched between two glass layers. The entire composite construction transfers light radiation to solar cells at the edge of the windows. It is based on a new combination of existing technologies because of it uses mature, mass-produced components - solar cells - as well as nanocomposite particles that are embedded inside the light-guide plate. They are integrated using an inexpensive and widely used method for making building windows. The result is an inexpensive, strong, stable, view quality-preserving solar energy-harvesting window that has no close competition. The diffusive solar cell window does not suffer from aging, and products that are made using diffusive solar cell window technology will be new entries to the solar power generation window market.

This article reports the synthesis and characterization of a novel thermally crosslinkable hole-transporting poly (fluorene-co-triphenylamine) (PFO-TPA) by Suzuki coupling reaction, followed with its application in the fabrication of multilayer light-emitting diodes by wet processes. The thermal, photophysical, and electrochemical properties of PFO-TPA were investigated by differential scanning calorimeter, thermogravimetric analysis, optical spectroscopy, and cyclic voltammetry, respectively. Thermally crosslinked PFO-TPA, through pendant styryl groups, demonstrates excellent thermal stability (T d > 400 °C, Tg = 152 °C), solvent resistance, and film homogeneity. Its highest occupied molecular orbital level (-5.30 eV) lies between those of PEDOT:PSS (-5.0 ~ -5.2 eV) and poly(9,9-dioctylfluorene) (PFO: -5.70 eV), forming a stepwise energy ladder to facilitate hole injection. Multilayer device with crosslinked PFO-TPA as hole-injection layer (HIL) (ITO/PEDOT:PSS/ HIL/PFO/LiF/Ca/Al) was readily fabricated by successive spin-coating processes, its maximum luminance efficiency (3.16 cd/A) were about six times higher than those without PFO-TPA layer (0.50 cd/ A). The result of hole-only device also confirmed hole-injection and hole-transport abilities of crosslinked PFO-TPA layer. Consequently, the device performance enhancement is attributed to more balanced charges injection in the presence of crosslinked PFO-TPA layer. The thermally crosslinkable PFO-TPA is a promising material for the fabrication of efficient multilayer polymer light-emitting diodes because it is not only a hole-transporting polymer but also thermally crosslinkable.

A transparent solar cell window module based on the integration of traditional silicon solar cells and organic–inorganic nanocomposite material was designed and fabricated. The transparent solar cell window module was composed of a nanocomposite light-guide plate and traditional silicon solar cells. The preparation of the nanocomposite light-guide plate is easy without modification of the traditional casting process, the nanoparticles sol can be added directly to the polymethyl methacrylate (PMMA) monomer syrup during the process. The solar energy collected by this window can be used to power up small household electrical appliances.

A series of fluorene derivatives containing nonsymmetric and bulky aromatic groups at C-9 position were synthesized and used for the preparation of blue-light-emitting copolyfluorenes (P1–P4) by the Suzuki coupling polycondensation. The copolymers were characterized by molecular weight determination, elemental analysis, differential scanning calorimeter, thermogravimetric analysis, absorption and emission spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Their decomposition temperatures and glass transition temperatures are 423–441 °C and >120 °C, respectively. In film state, the copolyfluorenes exhibit blue photoluminescence at 425–450 nm, which remains almost unchanged after annealing at 200 °C in air for 60 min. Polymer light-emitting diodes [ITO/PEDOT:PSS/P1–P4/Ca(50 nm)/Al(100 nm)] show stable blue-light emission under device operation with the CIE co-ordinates being between (0.16, 0.07) and (0.17, 0.09). The light-emitting diodes devices from P1 and P3 containing electron-deficient oxadiazole units display enhanced performance, with the maximum brightness and maximum current efficiency being (4510 cd/m2 and 2.40 cd/A) and (2930 cd/m2, 1.19 cd/A), respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2821–2834, 2009

A yellow flexible top-emission polymer light-emitting diode (TOPLED) was fabricated on cyclic olefin copolymer (COC) substrate. The light-emitting material was phenyl-substituted (p-phenylene vinylene) (HYPPV) polymer. The structure of TOPLED was COC/Ag/PEDOT:PSS/HYPPV/Ca/Ag. The Ag on COC was used as anode and the Ag on Ca was used as cathode. After anode Ag was thermally evaporated on COC substrate, the ultraviolet-ozone (UV-ozone) was treated on surface of anode Ag. The treating time was varied. The optimal treated time was 3 minutes. The luminous efficiency of TOPLED increased 42% with 3 minutes UV-ozone treatment.

Building integrated photovoltaics (BIPV) are an important application of future solar energy development. The incorporation of solar cells into windows must not only maintain indoor natural lighting but also generate electrical power at the same time. In our continuing effort to improve the design of diffusion solar window, a more fundamental and efficient three-layer structure—glass/EVA with TiO2nanoparticles embedded/glass—was proposed. In this work, a well-established ASAP ray-tracing model for a diffusive solar cell window was implemented to validate the outperformance of three-layer structure over primitive five-layer structure. Optical simulations were also implemented to perform its primary design for the determination of the optimal design parameters, such as the glass thickness, the EVA thickness, and the weight concentration of TiO2nanoparticles. Based on the simulation results, an optimal design for a three-layer diffusive solar cell window prototype was proposed. And the influence of both EVA thickness and glass thickness on the power edge-exitance (solar cell power generation efficiency) of a DSCW was thoroughly investigated.

A more efficient OLED device with blue emission characteristic of terfluorene has been achieved by using a novel molecular doping strategy, in which 4,5-diazafluorene was incorporated as the substitution group of terfluorene to facilitate electron injection from the metal cathode yet without altering emission characteristics.

This article reports on the investigation of anisotropic optical properties of vacuum-deposited thin films of high-efficiency blue-emitting ter(9,9-diarylfluorene)s using variable-angle spectroscopic ellipsometry. Under deposition conditions typical for thin-film organic devices, both real and imaginary parts of refractive indices of vacuum-deposited ter(9,9-diarylfluorene) films exhibit rather significant uniaxial anisotropy with the optical axis along the surface normal. In particular, for the absorption associated with the π–π* transition of the terfluorene backbone, they show substantially larger in-plane extinction coefficients than the out-of-plane extinction coefficients. It is thus inferred that the vacuum-deposited ter(9,9-diarylfluorene) molecules tend to align their molecular axes and π–π* transition dipole moments along the substrate surface as observed previously in spin-coated films of alkyl-substituted polyfluorenes or oligofluorenes, even though the present ter(9,9-diarylfluorene)s have ri...

Conjugated oligomers bearing 4,5,6,7-tetrahydro-5 S ,6 S -dioctyloxybenzothiophene as a central linkage were synthesized by Negishi's reagent ( n -Bu 2 ZrCp 2 ) promoted intramolecular cyclization of a diyne and subsequent Suzuki coupling reactions. The chirality in the central linkage originated from tartaric acid, which induced the conjugated backbone of oligomers to exhibit interesting optical activity.

This study proposes a method for recycling and activating the titanium oxide (TiO2)/fluorine-doped tin oxide (FTO) photoanode in dye-sensitized solar cells (DSCs) by repeated dye adsorption and desorption processes using various desorption agents. This simple and convenient method could be utilized to activate TiO2photoelectrodes for DSCs after the long-term operation. The devices are immersed in acidic, alkaline, and neutral media of various concentrations for desorption and then are soaked in the N719 solution again. The optimal device had an overall power conversion efficiency (AM 1.5 G, 100 mW/cm2) with 5 × 10−3 M NaOH solution as a desorption agent being 6.44% better than that of devices that had not undergone recycling and activation.

Treatment of benzylic or allylic dithioacetals with Me 2 ( i PrO)SiCH 2 MgCl in the presence of NiCl 2 (PPh 3 ) 2 catalyst yielded the corresponding i-propoxy(vinyl)silanes which are reduced with LiAlH 4 to afford vinylic silyl hydrides. These hydrides serve as the precursors for the syntheses of silylene-tethered σ,π-conjugated copolymers.

Palladium-catalyzed hydrosilylation of silyl-substituted butadienes 1 and 2 with MeSiCl2H has been investigated. Both steric effects and the presence of an aryl substituent affect the regiochemistry of the hydrosilylation reaction. Hydrosilylation of siloxanetethered bis-dienes 9 exhibits high regio- and diastereoselectivity.

Palladium-catalyzed hydrosilylation of silyl-substituted butadienes 1 and 2 with MeSiCl2H has been investigated. Both steric effects and the presence of an aryl substituent affect the regiochemistry of the hydrosilylation reaction. Hydrosilylation of siloxanetethered bis-dienes 9 exhibits high regio- and diastereoselectivity.

Treatment of benzylic or allylic dithioacetals with Me 2 ( i PrO)SiCH 2 MgCl in the presence of NiCl 2 (PPh 3 ) 2 catalyst yielded the corresponding i-propoxy(vinyl)silanes which are reduced with LiAlH 4 to afford vinylic silyl hydrides. These hydrides serve as the precursors for the syntheses of silylene-tethered σ,π-conjugated copolymers.

Conjugated oligomers bearing 4,5,6,7-tetrahydro-5 S ,6 S -dioctyloxybenzothiophene as a central linkage were synthesized by Negishi's reagent ( n -Bu 2 ZrCp 2 ) promoted intramolecular cyclization of a diyne and subsequent Suzuki coupling reactions. The chirality in the central linkage originated from tartaric acid, which induced the conjugated backbone of oligomers to exhibit interesting optical activity.

A new polymeric silver complex, [Ag(2)(L(2))(ClO(4))(2)] (L = 4,5-diazospirobifluorene), has been synthesized and shown to exhibit interesting luminescence properties in a single crystal. Structural analysis reveals a one-dimensional chain, which contains a [Ag(2)(L(2))](2+) dimer bridged with ClO(4)(-). The Ag...Ag distances are 2.776(1) and 4.575(1) A incorporated by two L ligands and by a ClO(4)(-) bridge, respectively.

Novel ter(9,9-diarylfluorene)s were synthesized by a Suzuki-coupling reaction of 2-bromofluorene (1) and 2,7-fluorenediboronic ester derivatives (3) with high isolated yields (63-86%). The X-ray structure analysis of ter(9,9'-spirobifluorene) (4aa) revealed that the conjugated chromophore adopts a helical conformation. This conformation effectively releases the steric interaction between the fluorene moieties and prevents inter-chromophore interactions. The introduction of aryl groups at the C9 position of fluorene was highly beneficial to the thermal and morphological stability of these oligomers. These terfluorenes exhibit intense blue fluorescence with excellent quantum yields both in solution ( approximately 100%) and in solid state (66-90%), and possess interesting reversible redox properties. Highly efficient blue light-emitting OLED devices were fabricated using 4aa and 4cc as emitters as well as hole transporters. The devices exhibit low turn-on voltage ( approximately 3 V) and high EL external quantum efficiency (2.5-3%).

We report charge-transport and related physical properties of terfluorenes with various C9 substitutions. Results show that by introducing slight spiroconjugation between a core chromophore and conjugated substitutions through spiro-linking, the bulky substitution not only serves as a spatial hindrance to enhance morphological stability and emission efficiency in thin films, but also bridges and enhances intermolecular charge transport under certain situations. Interestingly, such characteristics are acquired without altering major electronic properties of core chromophores, rendering it a flexible molecular scheme for tuning characteristics of functional molecules to meet various demands of different applications.

In this paper, we added CdSe/ZnS core/shell quantum dots (QDs) into anthracene-contained polymer. The photoluminescent (PL) characteristic of polymer/QD composite film could identify the energy transitions of anthracene-contained polymer and QDs. Furthermore, the electroluminescent (EL) characteristic of hybrid LED also identifies emission peaks of blue polymer and QDs. The maximum luminescence of the device is 970 cd/m(2) with 9.1 wt.% QD hybrid emitter. The maximum luminous efficiency is 2.08 cd/A for the same device.