Search results for "Solar cell"

Efficiency of concentration photovoltaic cells governed by luminescence processes

2013

The development of multi-junctions III-V semiconductors solar cells, that combine high conversion efficiency (over 40%) and capability of working under high illumination intensity (up to 1000 suns), has stimulated a rapid growth of concentrating photovoltaic (CPV) technology. The performance of these cells is based on the matching between the semiconductors band gap and the solar spectrum so as to optimize the current balancing between the subcells. This requirement is also important in connection with the CPV modules using lenses, mirrors, optical coupling compounds that introduce a wavelength dependent response to the sunlight. Therefore, care must be exercised in designing optimum cells …

3D Order for Improved Organic Solar Cells Effiency

2010

Donor-π-acceptors containing the 10-(1,3-dithiol-2-ylidene)anthracene unit for dye-sensitized solar cells

2012

Two donor-acceptor molecular tweezers incorporating the 10-(1,3-dithiol-2-ylidene)anthracene unit as donor group and two cyanoacrylic units as accepting/anchoring groups are reported as metal-free sensitizers for dye-sensitized solar cells. By changing the phenyl spacer with 3,4-ethylenedioxythiophene (EDOT) units, the absorption spectrum of the sensitizer is red-shifted with a corresponding increase in the molar absorptivity. Density functional calculations confirmed the intramolecular charge-transfer nature of the lowest-energy absorption bands. The new dyes are highly distorted from planarity and are bound to the TiO(2) surface through the two anchoring groups in a unidentate binding for…

The Relation between Photoconductivity Threshold and Open-Circuit Voltage in Organic Solar Cells

2022

Financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ/2020/08 implemented at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².

Fabrication and characterization of Donor/Acceptor heterojunction organic solar cells

2018

Results of initial development of organic solar cells having the Donor/Acceptor heterojunction structure with and without an exciton blocking layer are reported. Characterization is carried out in AM1.0 condition with 100 mW/cm2 incident optical power density. The best device has the exciton blocking layer and exhibits an open circuit voltage VOC = 0.43 V, a short circuit current density JSC = 2.35 mA/cm2 with a fill factor FF ≈ 50%, an external quantum efficiency (electrons/s over incident photons/s) EQE ≈ 5% and a power conversion efficiency of about 0.5%.

Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling

2013

Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language.…

Simulation analysis of Ruthenium-based Dye Sensitized Solar Cells

2016

Dye Sensitized Solar Cell (DSSC), usually referred as one of the most promising third generation photovoltaic devices, is an electrochemical device in which a molecule (i.e., the dye) chemisorbed onto the surface of a porous material absorbs the incident light and, thus, transfers an electron to the wide band gap semiconductor material. The injected electrons can diffuse through the semiconductor up to the collecting anode without the risk of recombination. The roles of the electrolyte which permeates the cell are to regenerate the ionized molecule and to implement a hole-transporting layer, allowing to repeat the abovementioned process. Thanks to this behaviour, semiconductors with large a…

Electro-optical characterization of highly efficient Dye-Sensitized solar cells

2015

Nowadays, a growing demand for free and clean energy requires the study and the development of new low-cost solar photovoltaic (PV) cells. Among them, Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes as sensitizers are assuming a great importance. The DSSCs under study are composed placing in succession a transparent conductive glass on which is screen-printed a mesoporous TiO2 thin film sensitized by a ruthenium based dye (N719), an electrolytic solution containing a redox couple (I-/I3-) and another conductive glass covered by a thin transparent catalyst platinum film. In this work, we have measured the main photoelectrochemical parameters of the above mentioned DSSCs at di…

Laser Beam Induced Current measurements on Dye Sensitized Solar Cells and thin film CIG(S,SE)2 modules

2017

Calculating the efficiency of a solar cell depends on a precise knowledge of its area. Indeed, the photoresponse uniformity is essential to improve the manufacturing process. In this work we report on Laser Beam Induced Current measurements performed on CIG(S,Se)2 modules and Dye Sensitized Solar Cells. These measurements, performed via a green and a red HeNe lasers both operating at an optical irradiance of 1 Sun, allowed to obtain an accurate photoresponse map of the specimens and highlighted the non-uniformities with a spatial resolution of 400 μm and 80 μm, respectively.

CulnSe2/Zn(S,O,OH) junction on Mo foil by electrochemical and chemical route for photovoltaic applications

2014

Electrodeposition is a convenient technique for the development of low cost materials for photovoltaic (PV) device processing. Using a single step electrodeposition route, several groups have fabricated CIS (CuInSe) and CIGS (CuInGaSe) films [1]. One of the most important requirements for successful application of one-step electrodeposition film formation, is the ability to control composition of the deposited films and to develop polycrystalline microstructures with a low surface roughness and high sintered density. In this preliminary work, CIS films were produced by single bath electrodeposition finding the optimal conditions in order to achieve a dense film with high crystallinity and u…