Search results for "Solar cell"

ZnO/CdTe/CuSCN, a promising heterostructure to act as inorganic eta-solar cell

2005

Abstract The ZnO/CdTe/CuSCN heterostructure was analyzed as a candidate to act as an inorganic eta -solar cell. A ZnO film consisting of single crystal nanocolumns was electrodeposited on a transparent conducting substrate which acts as n-type material. As absorber material we used CdTe, which was deposited on the ZnO columnar film by Metal Organic Chemical Vapor Deposition. In order to complete the eta -solar cell we deposited a CuSCN layer by chemical solution deposition. A conformal and uniform CdTe coverage of the ZnO columns was achieved, producing a very efficient light trapping effect. The effective absorption (∼87%) and effective reflectance (∼10%) of the complete heterostructure in…

Development of a High Granularity Photovoltaic Model That Considers Complex Nonuniform Shadow Conditions and Different Cell Temperatures

2012

In this paper is the development of a high granularity photovoltaic model that considers complex nonuniform shadow conditions and different cell temperatures. The model integrates the nonuniform shading characteristics such as different areas for each cell, different direct and indirect solar irradiations for each cell, and different temperatures. The area of the shadow on the PV module is found using image processing. The bond graph formalism facilitates the representation of the energy exchange between the different parts of the PV module. This complexity justifies the effort to develop a high-granularity tool. The proposed model is validated through experimental tests under shading condi…

Characterization of defect density states in MoOx for c-Si solar cell applications

Layers of MoOx have been deposited by thermal evaporation followed by post-deposition annealing (PDA). The density of states (DOS) distributions of the MoOx films were extracted deconvoluting the absorption spectra, measured by a phothermal deflection spectroscopy setup, including the small polaron contribution. Results revealed a sub-band defect distribution centered 1.1 eV below the conduction band; the amplitude of this distribution was found to increase with PDA temperature and film thickness.

Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells

2016

Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…

Strongly Coupled Cyclometalated Ruthenium Triarylamine Chromophores as Sensitizers for DSSCs

2016

A series of anchor-functionalized cyclometalated bis(tridentate) ruthenium(II) triarylamine hybrids [Ru(dbp-X)(tctpy)](2-) [2 a](2-) -[2 c](2-) (H3 tctpy=2,2';6',2''-terpyridine-4,4',4''-tricarboxylic acid; dpbH=1,3-dipyridylbenzene; X=N(4-C6 H4 OMe)2 ([2 a](2-) ), NPh2 ([2 b](2-) ), N-carbazolyl [2 c](2-) ) was synthesized and characterized. All complexes show broad absorption bands in the range 300-700 nm with a maximum at about 545 nm. Methyl esters [Ru(Me3 tctpy)(dpb-X)](+) [1 a](+) -[1 c](+) are oxidized to the strongly coupled mixed-valent species [1 a](2+) -[1 c](2+) and the Ru(III) (aminium) complexes [1 a](3+) -[1 c](3+) at comparably low oxidation potentials. Theoretical calculati…

Anthracene Based Conjugated Polymers: Correlation between π−π-Stacking Ability, Photophysical Properties, Charge Carrier Mobility, and Photovoltaic P…

2010

This article reports on the synthesis, characterization and properties of a series of anthracene−containing poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene)s (PPE−PPV) copolymers with general constitutional unit (Ph−C≡C−Anthr−C≡C−Ph−CH═CH−Ph−CH═CH−)n denoted AnE-PV. Solely linear (AnE-PVaa, -ad, -ae) and solely branched (AnE-PVbb) as well as mixed linear and branched (AnE-PVab, -ac, -ba, -cc) alkoxy side chains were grafted to the backbone in order to tune the π−π-stacking ability of the materials. It has been possible to establish a correlation between π−π-stacking ability, absorptive behavior, charge carrier mobility, solar cell active layer nanoscale morphology and resulting p…

Performance of dye-sensitized solar cells based on novel sensitizers bearing asymmetric double D−π−A chains with arylamines as donors

2012

Abstract Three novel, metal-free organic sensitizers bearing two asymmetric double donor-π-acceptor (D-π-A) chains ( DC1 - 3 ), each, and a reference dye containing single D-π-A chain ( SC ) with cyanoacrylic acid as electron acceptor are synthesized. Their photophysical, electrochemical properties and the performances of the corresponding dye-sensitized solar cells (DSSCs) are further investigated. The dyes, DC1, DC2 and DC3 contain one chain with diphenylamine and another chain with carbazole or phenothiazine as electron donor, while diphenylamine is only employed as electron donor in SC . Compared to the inferior solar energy to electricity conversion efficiency ( η ) of 2.82%, 4.66% and…

Persistent photovoltage in methylammonium lead iodide perovskite solar cells

2014

Open circuit voltage decay measurements are performed on methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells to investigate the charge carrier recombination dynamics. The measurements are compared to the two reference polymer-fullerene bulk heterojunction solar cells based on P3HT:PC60BM and PTB7:PC70BM blends. In the perovskite devices, two very different time domains of the voltage decay are found, with a first drop on a short time scale that is similar to the organic solar cells. However, two major differences are also observed. 65-70% of the maximum photovoltage persists on much longer timescales, and the recombination dynamics are dependent on the illumination intensity.

Polymer solar cells based on diphenylmethanofullerenes with reduced sidechain length

2011

Diphenylmethanofullerenes (DPMs) show interesting properties as acceptors in polymer bulk heterojunction solar cells due to the high open circuit voltages they generate compared to their energy levels. Here we investigate the effect of reducing the alkane sidechain length of the DPMs from C12 to C6 in the properties of the solar cell. This change leads to an increase in the electron mobility, thus allowing for a lower fullerene content, which in turn results in an increase in the short circuit current and, finally, in an increase in the efficiency of the device (from 2.3 to 2.6%) due to the higher concentration of the more absorbing polymer in the film. Atomic force microscopy images and ex…

Design, synthesis and photovoltaic properties of [60]fullerene based molecular materials

2005

Abstract The possibility to use new organic semiconductor materials, in place of silicon wafers, in the fabrication of photovoltaic devices on substrates offer the prospect of lower manufacturing costs, particularly for large area applications. Thus, one of the most promising areas in fullerene research involves its potential application, mixed with conjugated polymers, in mimicking photosynthesis and in the related solar energy conversion. The tendency to phase segregation in blends of C60 derivatives and conjugated polymers has to be optimized to improve both charge photogeneration and transport in photovoltaic devices. In order to optimize device performances, a great deal of work has be…