Search results for " Solar cell"
showing 10 items of 309 documents
Local Time-Dependent Charging in a Perovskite Solar Cell
2016
Efficient charge extraction within solar cells explicitly depends on the optimization of the internal interfaces. Potential barriers, unbalanced charge extraction, and interfacial trap states can prevent cells from reaching high power conversion efficiencies. In the case of perovskite solar cells, slow processes happening on time scales of seconds cause hysteresis in the current-voltage characteristics. In this work, we localized and investigated these slow processes using frequency-modulation Kelvin probe force microscopy (FM-KPFM) on cross sections of planar methylammonium lead iodide (MAPI) perovskite solar cells. FM-KPFM can map the charge density distribution and its dynamics at intern…
Fabrication and electro-optical characterization of Ruthenium-based Dye-Sensitized Solar Cells
2015
In this paper, we measure the main photoelectrical parameters of Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes at different irradiance levels, incident wavelengths, temperatures and hours of light soaking
Experimental characterization of Ruthenium-based Dye Sensitized Solar Cells and study of light-soaking effect impact on performance
2016
In this paper, we present an experimental investigation on the performance of Ruthenium-based Dye Sensitized Solar Cells (DSSCs) at different irradiance levels, incident wavelengths and hours of illumination. In particular, the measurements have been aimed at studying the performance variation due to light soaking effect since this phenomenon has noteworthy practical implications, such as stability tests of DSSCs. Our results show that the short circuit current density, the open circuit voltage and the conversion efficiency η increase with the hours of light soaking. Finally, the observed phenomenon is reversible, and thus the performance decreases again when the cell is kept in the dark.
Characterization of Thin Film CIG(S,Se)2 submodules using Laser Beam Induced Current Technique
2015
Nowadays, an important class of thin film solar cells consists of CuInGa(S,Se)2 (CIGSSe) solar cells, i.e., composed of Copper, Indium, Gallium, Sulfur and Selenide. Thanks to their electrical and optical properties and to the technological development, thin film integrated photovoltaic modules have nowadays obtained relatively good values of efficiency. In this work, we have performed the electrical and optical characterization of a CIGSSe sub-module by using both a solar simulator equipment and the Laser Beam Induced Current (LBIC) technique.
Colloidal Self-assembled Nanosphere Arrays for Plasmon-enhanced Light Trapping in Thin Film Silicon Solar Cells
2014
To realize high-efficiency thin-film silicon solar cells it is crucial to develop light-trapping methods that can increase absorption of the near- bandgap light in the silicon material. That can be achieved using the far-field scattering properties of metal nanoparticles (MNP) sustaining surface plasmons. The MNPs should be inserted in the back of the cell, embedded in the transparent conductive oxide (TCO) layer which separates the rear mirror from the silicon layers. In this way, a plasmonic back reflector (PBR) is constructed that can redirect light at angles away from the incidence direction and thereby increase its path length in the cell material. In this work, a novel technique is pr…
Effect of the linkage location in double branched organic dyes on the photovoltaic performance of DSSCs
2015
Two novel double branched D–π–A organic dyes (DB dyes) are synthesized to investigate the influence of the linkage location in DB dyes on the performance of dye-sensitized solar cells (DSSCs), where phenothiazine is introduced as a donor, thiophene–benzotriazole unit as the π-bridge and cyanoacrylic acid as the electron-acceptor. The photophysical, electrochemical and photovoltaic properties of the dyes are systematically investigated. The results show that the location of the linkage unit has a small effect on the physical and electrochemical properties of the dyes. However, when the dyes are applied in DSSCs, an obvious decline of short-circuit current (Jsc) and open-circuit voltage (Voc)…
Ultrafast Charge Separation at the CdSe/CdS Core/Shell Quantum Dot/Methylviologen Interface: Implications for Nanocrystal Solar Cells
2011
Exciton separation dynamics in the electron transfer system containing highly photostable CdSe/CdS core/shell nanocrystal quantum dots and adsorbed methylviologen was investigated by means of femtosecond absorption spectroscopy. The experiments revealed that electron extraction from the photoexcited core is possible, and the rate of the ET reaction strongly depends on the CdS shell thickness. A CdS associated exponential decay constant β of 0.33 A−1 was obtained reflecting the electronic barrier effect of the shell. These findings show that core/shell structures are well suited for the design of optimized QD-based solar cells.
Metal-free organic dyes with di(1-benzothieno)[3,2-b:2′,3′-d]pyrrole as an auxiliary donor for efficient dye-sensitized solar cells: Effect of the mo…
2019
Abstract A series of novel di(1-benzothieno)[3,2-b:2′,3′-d]pyrrole (DBTP)-based organic dyes (WL5-10) with D-D-π-A or D-D-A-π-A configurations are designed and the relationship between the properties and molecular configurations of these organic dyes are studied systematically. WL5,7–8 with D-D-π-A configuration incorporating triphenylamine or phenothiazine as donor and DBTP as auxiliary donor and WL9-10 with D-D-A-π-A configuration incorporating benzothiadiazole as an auxiliary acceptor are synthesized to study the effect of the molecular engineering on the photovoltaic performance. WL5,7–8 exhibit similar absorption spectra and high molar extinction coefficient. Especially, the dye WL5 wi…
Dithienopyrrolobenzothiadiazole-based organic dyes for efficient dye-sensitized solar cells
2014
Four novel D–π–A metal-free organic dyes DTP1–4 containing a dithienopyrrolobenzothiadiazole (DTPBT) unit were synthesized and applied in dye-sensitized solar cells, where DTPBT was employed as a π-spacer for the first time. The photophysical, electrochemical and photovoltaic properties of the dyes were systematically investigated. The dyes DTP1–4 showed broad absorption spectra and high molar extinction coefficient, resulting in high light harvesting efficiency. In addition, the impacts of donors and the thiophene unit as an additional π-spacer were also studied. The results showed that the dye DTP4 with triphenylamine as the donor exhibited better photovoltaic performance than DTP1–3 with…
Anti-recombination organic dyes containing dendritic triphenylamine moieties for high open-circuit voltage of DSSCs
2013
Abstract Three novel sensitizers with dendritic triphenylamine moieties were synthesized and used for dye-sensitized solar cells (DSSCs). Their absorption spectra, electrochemical and photovoltaic properties were extensively investigated. All three DSSCs exhibit high open-circuit voltage over 0.8 V. The photovoltaic results indicate that the dendritic triphenylamine units improve the open-circuit voltage, which is attributed to the retardation of charge recombination, demonstrating that non-planar and larger molecules exert better blocking function. Under standard global AM 1.5 solar conditions, the best performance of the DSSCs exhibits a short-circuit current density of 10.35 mA cm−2, an …