Search results for "Solar cells"
showing 10 items of 178 documents
Controlling the Phase Segregation in Mixed Halide Perovskites through Nanocrystal Size
2019
Mixed halide perovskites are one of the promising candidates in developing solar cells and light-emitting diodes (LEDs), among other applications, because of their tunable optical properties. Nonetheless, photoinduced phase segregation, by formation of segregated Br-rich and I-rich domains, limits the overall applicability. We tracked the phase segregation with increasing crystalline size of CsPbBr3–xIx and their photoluminescence under continuous-wave laser irradiation (405 nm, 10 mW cm–2) and observed the occurrence of the phase segregation from the threshold size of 46 ± 7 nm. These results have an outstanding agreement with the diffusion length (45.8 nm) calculated also experimentally f…
Photovoltaic module characteristics from CIGS solar cell modelling
2013
We describe our approach to the task of modelling, both at single cell structure and complete module levels, during the solar cell technology development process. This can give very helpful indications, in terms of global photovoltaic module characteristics, for the assessment of intermediate research results and planning of further experiments. We make reference specifically to the fabrication of thin film CIGS solar cells by means of single-step electrodeposition, a technique which appears fairly easy and low-cost but, at the same time, can lead to quite different structural and electrical properties.
Photovoltaic characterization of organic solar cells
2018
In recent years organic solar cells (SCs) have reached power conversion efficiencies above 10% [1]. Organic photovoltaics is indeed an intensively pursued research field because it promises high efficiency and low cost SCs. Organic materials have unique and useful optoelectronic properties, their chemical synthesis can be cheap and easy, and can be deposited in the form of thin films even on flexible plastic substrates by simple deposition techniques such as spinning, ink-jet printing and high vacuum thermal evaporation. Here we report results of the photovoltaic characterization of organic SCs having the donor (D)/acceptor (A) heterojunction structure [2]. The SCs, fabricated by vacuum the…
Diphenylmethanofullerene (DPM): a new and efficient acceptor in bulk heterojunction solar cells
2005
Plasmonic nanostructures for light trapping in thin-film solar cells
2019
M.J.M. acknowledges funding from FCT through the grant SFRH/BPD/115566/2016. ALTALUZ (Reference PTDC/CTM-ENE/5125/2014). The optical properties of localized surface plasmon resonances (LSPR) sustained by self-assembled silver nanoparticles are of great interest for enhancing light trapping in thin film photovoltaics. First, we report on a systematic investigation of the structural and the optical properties of silver nanostructures fabricated by a solid-state dewetting process on various substrates. Our study allows to identify fabrication conditions in which circular, uniformly spaced nanoparticles are obtainable. The optimized NPs are then integrated into plasmonic back reflector (PBR) st…
Donor-acceptor “double-cable” polythiophene with tunable acceptor content
2004
Charge Transport and Recombination Layers for Perovskite Solar Cells
2020
El trabajo de esta tesis ha sido estructurado en tres secciones. En el capítulo 3, se estudió el rendimiento y la estabilidad de células solares tipo p–i–n de perovskita con y sin capa de transporte de cargas dopada. En el contacto p, el reemplazo de las capas de transporte de carga dopadas por alternativas no dopadas mejoró el rendimiento del dispositivo. En primer lugar, se identificó una barrera Schottky de inyección/extracción de carga en la interfaz ITO-TaTm. Mediante la inserción de una capa muy fina de la molécula de dopante tipo p entre el ITO y la HTL se consiguió aliviar dicha barrera. Esta estrategia da como resultado una reducción importante de la absorción parasítica. Esto cond…
Perovskite CH3NH3PbI3–XClx Solar Cells and their Degradation (Part 1: A Short Review)
2021
Development of hybrid organic-inorganic perovskite solar cells (PSC) has been one of the hottest research topics since 2013. Within brief literature review, we would like to achieve two objectives. Firstly, we would like to indicate that a whole set of physical properties, such as high change carrier mobility, very low recombination rates, large carrier life time and diffu-sion length, large absorption coefficients and very weak exciton binding energies, are defining high power conversion efficiency (PCE) of methyl ammonium lead trihalide SC. The second objective is to draw attention to some, in our opinion, important aspects that previously have not been satisfactory addressed in literatur…
Challenges with balancing excitations in intermediate-band solar cells
2015
New insight into the potential of practical solar cells can be given through alternative modeling approaches like Monte Carlo simulations. In the present work, the performance of intermediate band solar cells was examined by this method. It is demonstrated that the balance of excitations from the valence band to the intermediate band and from the intermediate band to the conduction band is of great importance for the performance of such cells. Several cases with different distributions of photons given by ASTM standards have been employed in order to detect spectrum sensitivity. Incident photons are accounted for as they interact with the electrons in the valence band or in the intermediate…
Review on up/down conversion materials for solar cell application
2012
The present paper reviews the methods of photon up- and down conversion strategies for improving the efficiency of solar cells. Photons with a lower energy than the band gap will be lost in a normal solar cell. The principle of the up conversion technique is that two or more photons are converted into a photon with energy higher than the band gap energy. High energy photons will lose the energy above the band gap energy limit. Down conversion is a process where a high energy photon is converted into several lower energy photons with energies above the band gap. A description is given of the most common methods and materials for these conversions resulting in higher solar cell efficiencies.