Dye-sensitized Solar Module Research Articles

Design and analysis of a highly reliable large-area Z-type transparent module for dye-sensitized solar cells

Abstract The design methodologies for large-area transparent dye-sensitized solar cells (DSSCs) and modules for building-integrated photovoltaic (BIPV) windows are presented. Using electrochemical impedance spectroscopy and the optical/electrical measurements of a small-sized (∼9 × 5 mm) test cell, the basic circuitry of a DSSC is generated in a unit cell for building the 2-dimensional equivalent circuit model of a large-area Z-type transparent DSSC module (300 × 300 mm) on P-Spice. Based on solar irradiation at a window-side monitored for a year, we have proposed a DSSC module design that generates the maximal electrical energy for the best levelized cost of electricity. While simulations using the developed model estimated a module efficiency of ∼3.23% and an annual electrical energy generation of 448 kWh/m2, the fabricated module with a cell width of ∼18 mm exhibited an efficiency of ∼3.19%; the design is also conducive for practical manufacturing and thermal reliability. The developed model demonstrates the operational behaviors of DSSC modules under local shadowing conditions that match with the experiments. The feasibility of the DSSC as a reverse diode, working as a distributed by-pass diode eliminating the current mismatch loss is also demonstrated; this is beneficial for long-term operations. This work can be applied to other types of DSSCs and can be used for producing DSSC-based BIPV windows.

A scalable monitoring method of dye uptake in dye-sensitized solar cells and modules: Optimization of Z907 impregnation time for long term stability

In the fabrication of dye-sensitized solar cells (DSSC), dye coating is a time-consuming and critical step. Rapid sensitization processes suitable for DSSC industrialization require appropriate dye loading measurement methods. We present a non-destructive method, in which we monitor a fast continuous-flow dyeing process by UV–Vis analysis on the exhaust solution flowing out of the cells. The proposed approach has the advantage over a direct optical analysis on the photo-anode of being independent from film non-uniformity, transparency and area. The monitoring method was successfully applied to evaluate the dependence of Z907 dye adsorption kinetic on temperature, flow rate and dye initial concentration, both on small cells and on 23cm×23cm DSSC modules. Saturation of dye uptake is reached after 40min for 0.3mM dye solution and the rate constant is determined to be 0.114min−1. The results are discussed and correlated with DSSC photovoltaic performances, showing that a longer coloration time has a beneficial influence on long term stability.

Energy Saving Assessment of Semi-Transparent Photovoltaic Modules Integrated into NZEB

Photovoltaic semi-transparent materials (STPV) integrated into glazing systems can offer good potential for energy saving to buildings, influencing heating loads, cooling loads, and lighting, as well as electricity production. Moreover, with the new stringent regulations issued by various European countries, following the Energy Performance of Buildings Directive (EPBD, 2010/31/EC), the building envelope, including the glazing elements, needs to have high thermal performance to guarantee Nearly Zero Energy Building (NZEB) behavior. This work presents an assessment of energy saving potential of 4 different types of STPV with respect to conventional double pane glass. Dye sensitized solar modules (DSM) and thin film modules were considered in the study. Simulations based on an IEA reference office building (STD) and on reference buildings prescribed by the new Italian building energy performance regulation (NZEB) were carried out. All the glazing peculiarities could be simulated using only one simulation tool, namely IDA ICE 4.7.1. Dye sensitized solar modules resulted as the best performing devices for all orientations and climate zones. The work also evidenced how the requirements of NZEB seem to be too stringent for insulation properties, especially for the climate zone of Rome.

Assembly Considerations for Dye-Sensitized Solar Modules with Polymer Gel Electrolyte

Parallel, portable dye-sensitized solar cell modules with 5 × 5 cm2 of area containing either a polymer gel electrolyte or a standard liquid electrolyte were assembled and characterized as a function of time. For modules sealed with the thermoplastic Surlyn, a rapid loss of performance was observed, due to an insufficient protection of the metallic current collectors (silver grids) of the module and, sometimes, also associated with electrolyte leakage. Similar results were obtained using a glass frit layer as the only material for protective overcoat of the silver grids. Thus, the combination of the Surlyn with a glass frit was investigated. The process based on the combination of two materials allowed achieving a more effective sealing, with enhanced process yield and sample reproducibility. The modules assembled by this method, filled with either a polymer gel electrolyte or liquid electrolyte, showed an enhanced stability. Concomitantly, the formulation of the polymer gel electrolyte was also addressed...

Design of a photochemical water electrolysis system based on a W-typed dye-sensitized serial solar module for high hydrogen production

A W-typed dye-sensitized serial solar module (W-typed DSSM) was designed for hydrogen production from water electrolysis. The optimal thickness and width of the TiO2 electrode film were 12μm and 5mm, and the optimal thickness of Pt counter electrode film was 4nm, respectively. The photocurrent density, open circuit voltage, and fill factor were 2.13mAcm−2, 3.51V, and 0.61, respectively, for a serial module assembled from five unit cells, which resulted in an overall conversion efficiency of 4.56%. The obtained voltage increased with increasing number of unit cells connected, and was 3.51V in the five column fabricated W-typed DSSM. 2.1mLh−1 of hydrogen gas was emitted when a W-typed DSSM assembled from five columns was connected to carbon electrodes in a water electrolysis system. The rate of hydrogen evolution in the five columned W-typed DSSM was 0.00213Lh−1. Therefore, the actual light-hydrogen conversion was calculated to be 2.02%.

A perspective on the production of dye-sensitized solar modules

An overview of the state of the art dye solar module technology and innovations required for further development is presented.

A Semi-experimental Method for Fast Evaluation of the Performance of Grid-type Dye-sensitized Solar Module

A Semi-experimental Method for Fast Evaluation of the Performance of Grid-type Dye-sensitized Solar Module

Computational modeling and experimental analysis on the improvement of current mismatch in a W-type series-connected dye-sensitized solar module

Abstract A W-type series-connected dye-sensitized solar module (W-type DSC module) has a significant drawback of current mismatch attributed to its structural characteristics. This drawback is caused by low performance of the back-illuminated cell resulting from light loss. In this study, we attempted to alleviate this phenomenon by adjusting the TiO 2 thickness of the back-illuminated cell in a W-type DSC module. To demonstrate this, modeling of the back-illuminated cell as a function of the TiO 2 thickness and simulation analysis of the W-type DSC module were conducted. The modeling was implemented using the power electronic simulation tool on the basis of the coefficient extraction from experimental data and the simple interpolation method. As a result, it was demonstrated that the performance of the back-illuminated cell improves by adjusting the TiO 2 thickness, resulting in an improvement in the current mismatch by balancing the current between neighboring cells.

The enhancement of dye adsorption in dye-sensitized solar module by an electrical adsorption method

Dye-sensitized solar cell (DSC) has been considered as a strong alternative to conventional photovoltaic devices. The highest efficiency reached over 12%. Therefore, recent DSC researches extended the scope of the investigation such as the scaling-up and commercialization. In this work, the electrical dye-adsorption method was proposed for the faster dye-adsorption. Fast dye-adsorption is considerably effective to enhance the productivity of DSC because adsorption process takes the longest time in the whole process. This work focused on the analysis of electrical adsorption process and its application to a large DSC module as a real power source. The effect of electrical adsorption was confirmed by the change of photocurrent and absorbance of dye-dissolved solution. The proposed process was applied to large DSC modules and performance dependence was investigated according to the adsorption time. After the dye-adsorption for 6h, an efficiency of a DSC module electrically dye-adsorbed was 51.5% higher than that of a DSC module conventionally dye-adsorbed. As a result, the adsorption time of DSC module was much shortened from 18 to 6h by the proposed method.

Sol-gel based TiO2 paste applied in screen-printed dye-sensitized solar cells and modules

A simple manufacturing process based on screen-printing is crucial for a successful commercialization of dye-sensitized solar cells (DSSCs). We developed the sol–gel based TiO2 paste in such a way that solely a single step deposition is sufficient to realize a sponge-like structure of the layer assuring its high activity in DSSCs. For the first time the sol–gel based TiO2 paste was screen printed and tested in DSSC masterplates and PV mini-modules. Electroluminescence imaging of the mini-module proved layer homogeneity and no manufacturing defects. The conversion efficiency of the PV mini-module with the active area of 75cm2 reaches 5.7% at STC.

Glass Frit Dissolution Influenced by Material Composition and the Water Content in Iodide/Triiodide Electrolyte of Dye-Sensitized Solar Cells

To ensure long-term stable dye-sensitized solar cells (DSCs) and modules, a hermetic sealing is required. This research investigates the chemical stability ofI-/I3-redox electrolyte and four different glass frits (GFs). Sintered GF layers were openly exposed to nonaqueous redox electrolyte and redox electrolyte with 1, 5, and 10 wt% H2O in thin, encapsulated cells. The change inI3−absorbance was assigned to a reaction between the GF andI-/I3-electrolyte and was used to evaluate the chemical stability of the different GFs. TheI3−absorbance change was monitored over 100 days. Two out of the four GFs were unstable when H2O was added to the redox electrolyte. The H2O caused metal ion leaching which was determined from EDX analysis of the inorganic remains of electrolyte samples. A GF based on Bi2O3–SiO2–B2O3with low bond strength leached bismuth into electrolyte and formed theBiI3-complex. A ZnO–SiO2–Al2O3-based GF also became unstable when H2O was added to the redox electrolyte. Leaching of zinc ions due to exchange with H+resulted in the formation of a zinc-iodine compound which causedI3−depletion. By applying the test design to different types of GFs, the material suitability in the DSC working environment was investigated.

Fabrication and Characterization of Interconnected Grid-type Dye-Sensitized Solar Modules

Fabrication and Characterization of Interconnected Grid-type Dye-Sensitized Solar Modules

Improvement on the Long-Term Stability of Dye-Sensitized Solar Module by Structural Alternation

Dye-sensitized solar cell (DSC) module still lacks the long-term stability because of a volatile electrolyte. In this work, structural alternation of DSC parallel modules was proposed for high performance and stability. In the conventional module, the adhesion with the photo/counter electrodes was not stable with only one layer of sealant so that the stability was poor. On the other hand, buried grid module proposed in this work is possible to be stably sealed with only one layer of sealant. In this structure, grid electrodes are leveled with the same height of transparent conductive oxides (TCOs) because grid electrodes are inserted under furrows of etched TCOs. Consequently, the buried grid module had better long-term stability than conventional module. Additionally, the photo-current and efficiency were improved by the sonicated grid and the light scattering layer.

Improvement on the Long-Term Stability of Dye-Sensitized Solar Module by Structural Alternation

Dye-sensitized solar cell (DSC) module still lacks the long-term stability because of a volatile electrolyte. In this work, structural alternation of DSC parallel modules was proposed for high performance and stability. In the conventional module, the adhesion with the photo/counter electrodes was not stable with only one layer of sealant so that the stability was poor. On the other hand, buried grid module proposed in this work is possible to be stably sealed with only one layer of sealant. In this structure, grid electrodes are leveled with the same height of transparent conductive oxides (TCOs) because grid electrodes are inserted under furrows of etched TCOs. Consequently, the buried grid module had better long-term stability than conventional module. Additionally, the photo-current and efficiency were improved by the sonicated grid and the light scattering layer.

Application of Dye-Sensitized Solar Cell Technology in the Tropics: Effects of Air Mass on Device Performance

Abstract - The performance of a Dye-Sensitized Solar Module (DSSM) of active area 175.12 cm 2 has been investigated at a tropical climate area located 1.28˚S, 35.81˚E. Outdoor current density-voltage ( J-V ) characterizations were carried out at different AM values. The DSSM’s performance parameters; short circuit current density ( J sc ), open circuit voltage ( V oc ), fill factor ( FF ) and solar-to-electricity conversion efficiency ( η ) were extracted from the J-V characteristics. The DSSM’s V oc reduced linearly by 2.05% from 8.31 V to 8.14 V as AM increased from 1 to 1.09. J sc reduced linearly by 26.06% from 1.04 x 10 -3 Acm -2 to 7.69 x 10 -4 Acm -2 as AM increased from 1 to AM 1.09. FF increased linearly by 19.05% from 0.51 to 0.63 as AM increased from 1 at 1.09. η increased by 32.77% from 1.77% to 1.19% as AM increased from 1 to 1.09. The DSSM performed better during afternoon than morning hours. The results may be useful in tuning Dye-Sensitized Solar Cells (DSSCs) meant for use in the tropics. The design of Net Zero Energy (NZE) buildings in the tropics can also benefit from these findings.

Integration of Dye-Sensitized Solar Cells, Thermoelectric Modules and Electrical Storage Loop System to Constitute a Novel Photothermoelectric Generator

This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module.

Monolithic all-solid-state dye-sensitized solar module based on mesoscopic carbon counter electrodes

A monolithic all-solid-state dye-sensitized solar cell (DSSC) module based on mesoscopic carbon counter electrodes with high stability has been developed, which offers a promising prospect for commercial applications. Based on the design of a triple layer structure, all the layers are constructed on a single conducting glass substrate by screen-printing. A typical monolithic all-solid-state DSSC module, which consists of five series-interconnected unit cells, shows an overall energy conversion efficiency of 2.57% and a maximum output of 156.9mW. In the case of applying a solid-state polymer electrolyte, we have developed a novel sealing method for all-solid-state DSSCs. Endurance tests were carried out to investigate the stability of the module under a hot and high humidity environment (60°C, 85%RH) and heat and cool cycle stress (−10 and 60°C), which indicated that the sealing method improved the stability of the module effectively.

How to improve the performance of dye-sensitized solar modules by “back leads”

The modules with holes on the counter electrode substrate for photocurrent collection with thin wires were investigated by simulation. This type of module can perform high efficiency for its high open area ratio. An improved model based on our previous work was used to optimize this type of module. By simulation, we found that hexagonal cell is the best choice for this kind of module, and the optimized length of silver finger is related to the assemblage technique. Open area ratio of more than 90% and aperture area efficiency of more than 10% can be easily achieved based on the small area cell with efficiency of 11.1%.

Optimizing Performance of Dye-Sensitized Solar Module under Fluorescent Light Condition

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Durability of Dye-Sensitized Solar Cells and Modules

It was investigated that the intrusion of water into the electrolyte was the most critical reason for the low stability of a dye-sensitized solar cell. To prevent the water intrusion, robust solar cells and submodules with a novel protection layer of metal circuit and tightly sealing package was developed. The excellent stability of the cell with ionic liquid electrolyte at high temperature conditions was also reveled. The resulting cell employing noble construction and ionic liquid electrolyte showed an extremely high stability to pass several endurance tests standardized in JIS for the stability of the photovoltaic submodule.