Search results for "Solar cells"
showing 10 items of 178 documents
Modulating the luminance of organic light-emitting diodes via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode
2020
Nanoscale 12(9), 5444-5451 (2020). doi:10.1039/D0NR00724B
Luminescence properties of III-V multi-junctions solar cells
2012
The recent achievement of multi-junctions solar cells, based on III-V semiconductors, exceeding 43% efficiency, has stimulated a rapid growth of concentration photovoltaic (CPV) technology. The large efficiency of these cells is based on the matching between the semiconductors band gap and the solar spectrum and the capability of working under concentrated illumination, up to ~1000 suns. The research pays, therefore, attention to investigate in detail the mechanisms that affect the conversion efficiency, such as the non radiative losses that increase the cell temperature thus favoring the electron-hole (e-h) recombination. With the aim to clarify the performances of these III-V cells, here …
The origin of slow electron recombination processes in dye-sensitized solar cells with alumina barrier coatings
2004
We investigate the effect of a thin alumina coating of nanocrystalline TiO2 films on recombination dynamics of dye-sensitized solar cells. Both coated and uncoated cells were measured by a combination of techniques: transient absorption spectroscopy, electrochemical impedance spectroscopy, and open-circuit voltage decay. It is found that the alumina barrier reduces the recombination of photoinjected electrons to both dye cations and the oxidized redox couple. It is proposed that this observed retardation can be attributed primarily to two effects: almost complete passivation of surface trap states in TiO2 that are able to inject electrons to acceptor species, and slowing down by a factor of…
Improving Perovskite Solar Cells: Insights From a Validated Device Model
2017
To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of contacts, the electron and hole transport layers, charge generation, drift and diffusion of charge carriers and recombination. The simulation to the experimental data of vacuum-deposited CH3NH3PbI3 solar cells over multiple thicknesses has been fit and the device behavior under different operating conditions has been studied to delineate the influence of the external bias, charge-carrier mobilities, e…
State selective electron injection in non-aggregated titanium phthalocyanine sensitised nanocrystalline TiO2 films
2004
We describe a novel titanium phthalocyanine that shows no aggregation when anchored to nanocrystalline TiO2 films through its axial carboxylated ligand without the use of co-adsorbents; state selective electron injection into the TiO2 is demonstrated, resulting in efficient photocurrent generation in dye sensitised photoelectrochemical solar cells. Palomares Gil, Emilio J, epagil@alumni.uv.es
Vacuum processed perovskite solar cells
2017
El objetivo de la tesis es el desarrollo de materiales y métodos de deposición de capas de perovskita utilizando procesos de alto vacío, principalmente mediante co-evaporación. Para la fabricación de los dispositivos, se han empleado y optimizado diferentes materiales transportadores de electrones y de huecos. La tesis está estructurada de la siguiente manera:Capítulo 1: se desarrolla un método de deposición novedoso para la preparación de capas delgadas de perovskitas mixtas iodo-bromo.Capítulo 2: se presenta el estudio de diferentes derivados del fullereno como materiales transportadores de electrones para conseguir células solares de perovskita de alta eficiencia.Capítulo 3: se optimiza …
Single junction and tandem perovskite solar cells
2017
En este trabajo hemos estudiado diferentes métodos para preparar dispositivos fotovoltaicos de perovskitas. Se han cumplido los tres objetivos definidos al inicio de este periodo de investigación: 1. Hemos establecido con éxito un método estable y reproducible para la fabricación de células solares de perovskita procesadas desde disolución, empleando acetato de plomo y MAI como materiales precursores. 2. Hemos conseguido sintonizar el "bandgap" de perovskitas mixtas de bromuro y yoduro para alcanzar un valor de 2.0 eV, aprovechando las propiedades estabilizadoras de los cationes Cs+ y FA. Hemos investigado perovskitas de doble halogenuro y doble catión Cs0.15FA0.85Pb(Br0.7I0.3)3, fabricadas…
Empowering Photovoltaics with Smart Light Management Technologies
2021
The daily Sun supplies the continents of the Earth with four times more energy than humanity consumes in a year. This enormous potential of solar energy to generate clean energy is therefore driving great efforts to replace conventional and unsustainable fossil fuel consumption that damages our climate and our environment. Solar photovoltaic (PV) is emerging as the fastest growing renewable energy technology in the world, yet its share to the electricity production currently is less than 3%. While coal and gas remain key to electricity production, the climate crisis demands a fast transition to a carbon-neutral energy system. In the year 2019, the PV industry produced solar panels with a ca…
Analysis of Transition Metal Oxides based Heterojunction Solar Cells with S-shaped J-V curves
2020
The use of transition metal oxides for the selective carrier contact in the crystalline silicon solar cells technology is rising to interest for the excellent optoelectrical properties of these materials whose implementation, however, can result in lousy performing cells due to an S-shaped electrical characteristic. In this paper, we fabricated solar cells showing S-shaped J-V curve and carried out an analysis of the reasons of such behavior using a model involving the series of a standard cell equivalent circuit with a Schottky junction in order to explain these atypical performances. A good matching between the experimental measurements and the adopted theoretical model was obtained. The …
Consistent device simulation model describing perovskite solar cells in steady-state, transient, and frequency domain
2019
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsami.9b04991