Solar cells assembly

Such a panel of solar cells is encapsulated by pol5rmeric encap-sulants to form a solar cell assembly. This assembly may be further sandwiched between two protective outer layers to form a weather resistant module. The protective outer layers are formed from sufficiently transparent material to allow photons to reach the solar cells. In modules, where PVB is used as the encapsulant material, it has been foimd that the PVB tends to discolor over time, when in contact with an oxidizable metal component. 

Choi, Y.J., Kim, D.W., Photovoltaic performance of dye-sensitized solar cells assembled with hybrid composite membrane based on polypropylene non-woven matrix. Bull. Korean Chem. Soc., 2011, 32, 605-608. 

In 2001, a dye-sensitized solar cell assembled with a gel network polymer electrolyte based on polysiloxane and PEO, containing 20 wt% of Lil, 5 wt% of h and 150 wt% of the mixture ethylene carbonate (EC)/propylene carbonate (PC) (3 1 v/v) was reported. EC is a high viscosity solvent with high dielectric constant, which is favorable for salt dissociation. However, this material has a tendency to crystallize at low temperature, causing phase separation between the plasticizer and the polymer matrix. Thus, organic solvents such as PC are used to form binary organic solvents with EC and homogeneous gel polymer electrolytes can be obtained. The fully cross-linked electrolyte presented ambient conductivity of 1.1 x 10 S cm and... 

Biancardo and co-workers assembled a semitransparent quasi-solid state dye-sensitized solar module connecting in series solar cells assembled with a gel electrolyte. Each individual cell presented an efficiency of 1% under 100 mW cm" . The efficiency of the whole module composed 23 cells (active area of 625 cm ) reached 0.3%. The authors claimed that, although the efficiency was higher for modules assembled with liquid electrolytes, the use of the gel electrolyte clearly improved the performance of the cells after 1 month, leading to devices with extended lifetime. ... 

Photovoltaic (PV) solar cells, which convert incident solar radiation directly into electrical energy, today represent the most common power source for Earth-orbiting spacecraft, such as the International Space Station, where a photovoltaic engineering testbed (PET) is actually assembled on the express pallet. The solid-state photovoltaics, based on gallium arsenide, indium phosphide, or silicon, prove capable, even if to different extents and with... 

Given the actual scenario, one can state that the emerging field of nanotechnology represents new effort to exploit new materials as well as new technologies in the development of efficient and low-cost solar cells. In fact, the technological capabilities to manipulate matter under controlled conditions in order to assemble complex supramolecular structures within the range of 100 nm could lead to innovative devices (nano-devices) based on unconventional photovoltaic materials, namely, conducting polymers, fuUerenes, biopolymers (photosensitive proteins), and related composites. 

Hyun et al. [345] prepared PbS Q-dots in a suspension and tethered them to Ti02 nanoparticles with a bifunctional thiol-carboxyl linker molecule. Strong size dependence due to quantum confinement was inferred from cyclic voltammetry measurements, for the electron affinity and ionization potential of the attached Q-dots. On the basis of the measured energy levels, the authors claimed that pho-toexcited electrons should transfer efficiently from PbS into T1O2 only for dot diameters below 4.3 nm. Continuous-wave fluorescence spectra and fluorescence transients of the PbS/Ti02 assembly were consistent with electron transfer from small Q-dots. The measured charge transfer time was surprisingly slow ( 100 ns). Implications of this fact for future photovoltaics were discussed, while initial results from as-fabricated sensitized solar cells were presented. 

Lancelle-Beltran, E. Prene, P Boscher, C. Belleville, R Buvat, P Lambert, S. Guillet, F. Boissiere, C. Grosso, D. Sanchez, C. 2006. Nanostructured hybrid solar cells based on self-assembled mesoporous titania thin films. Chem. Mater. 18 6152-6156. 

The QD-MWNT hybrid structures were formed via the assembly of quantum dot (QD) on the surface of MWNTs in aqueous solution (Jares-Erijman and Jovin, 2003), which shows an excellent solubility in aqueous solution, and owns potential application in bioassay, bio-conjugation, and biosensors as well as solar cell. For example, incorporation of QDs and SWNTs into the poly(3-octylthiophene)-(P3OT)... 

In addition to their potential use as structural composites, these macroscopic assemblies of nanocarbons have shown promise as mechanical sensors [83], artificial muscles [84], capacitors [85], electrical wires [59], battery elements [85], dye-sensitized solar cells [86], transparent conductors [87], etc. What stands out is not only the wide range of properties of these type of materials but also the possibility of engineering them to produce such diverse structures, ranging from transparent films to woven fibers. This versatility derives from their hierarchical structure consisting of multiple nano building blocks that are assembled from bottom to top. 

In this review article, the functions of polymers and molecular assemblies for solar energy conversion will be described including photochemical conversion models, elemental processes for the conversion such as charge separation, electron transfer, and catalysis for water decomposition, as well as solar cells. 

The assembly of solar cells based on copper complexes required 2 optimization and multilayered photoanodes with a compact 2 underlayer, necessary to suppress the back recombination from the exposed FTO contact. The photoelectrochemical characterization carried out with a 0.2 M Cu(I)/Cu(II) electrolyte (Cu(II) molar... 

On a side note, Ouskova and co-workers also reported that the composite of magnetic /i-FejOs nanorods in 5CB showed lower threshold voltages than pure 5CB, and that the sensitivity of the nematic liquid crystal to external magnetic fields was increased in the presence of such magnetic nanorods [451]. Finally, several groups interested in the macroscopic organization and orientation of nanorods also reported on the formation of a lyotropic liquid crystal phase induced by the self-assembly of polymer-coated semiconductor nanorods [453—457], which might be used to improve the device performance, for example, of solar cells. 

A solid-state solar cell was assembled with an ionic liquid—l-ethyl-3-methylimidazolium bis(trifluoromethanesulfone)amide (EMITFSA) containing 0.2 M lithium bis(trifluoromethanesulfone)amide and 0.2 M 4-tert-butylpyridine—as the electrolyte and Au or Pt sputtered film as the cathode.51,52 The in situ PEP of polypyrrole and PEDOT allows efficient hole transport between the ruthenium dye and the hole conducting polymer, which was facilitated by the improved electronic interaction of the HOMO of the ruthenium dye and the conduction band of the hole transport material. The best photovoltaic result ( 7p=0.62 %, 7SC=104 pA/cm2, FOC=0.716 V, and FF=0.78) was obtained from the ruthenium dye 5 with polypyrrole as the hole transport layer and the carbon-based counterelectrode under 10 mW/cm2 illumination. The use of carbon-based materials has improved the electric connectivity between the hole transport layer and the electrode.51... 

Quasi-solid state dye-sensitized solar cells (DSCs) have been constructed using a new polymeric ionic fluid as the electrolyte.119 The electrolyte was synthesized by the sol-gel route using MTMSPI+I as the precursor that was made by derivatizing methylimidazolium with triethyoxysilane. Condensation of this material in the presence of formic acid and in the absence of water led to Si-O-Si-O-type polymerization and formation of a polysilsesquioxane-type structure. When this material was mixed with iodine, it served as a redox electrolyte for DSCs. The DSCs made this way are robust and easy to assemble but their efficiency of 3.1% is relatively low. However, possible improvement lies in modification of the organic groups attached to the polysilsesquioxane backbone. 

This volume of the series focuses on the photochemistry and photophysics of metal-containing polymers. Metals imbedded within macromolecular protein matrices form the basis for the photosynthesis of plants. Metal-polymer complexes form the basis for many revolutionary advances occurring now. The contributors to many of these advances are authors of chapters in this volume. Application areas covered in this volume include nonlinear optical materials, solar cells, light-emitting diodes, photovoltaic cells, field-effect transistors, chemosensing devices, and biosensing devices. At the heart of each of these applications are metal atoms that allow the assembly to function as required. The use of boron-containing polymers in various electronic applications was described in Volume 8 of this series. 

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