Search results for "photovoltaicS"

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…

Analysis of Solar Energy Resources in Southern Poland for Photovoltaic Applications / Analiza Struktury Zasobów Energii Słonecznej Obszaru Polski Poł…

2013

Abstract The article presents an analysis of the resources and the structure of the solar energy in the area of Southern Poland on the basis of complete meteorological data from the AGH University of Science and Technology in Krakow in 2009. An analysis attempt of its use for photovoltaic conversion using different modules with different spectral characteristics of absorbers was made. These latest methods for characterizing the structure of solar energy resources such as: distributions throughout the year: sky clearness or cloudiness indexes, the average values of photon energy (APE) and the contents of the useful fraction (UF) of the solar spectrum, are not yet widely known and used as in …

Time-dependent electric field in Al/CdTe/Pt detectors

2015

Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from bias-induced time instability (polarization). Polarization phenomena cause a progressive time-degradation of the spectroscopic performance of the detectors, due to hole trapping and detrapping from deep acceptor levels that directly control the electric field distribution. In this work we present experimental investigations on the electric field profile of planar Al/CdTe/Pt detectors by means of Pockels effect measurements. The time/temperature dependence of the electric field was investigated in a long time window (up to 10 h) and the correlation with the reverse c…

Polarization phenomena in Al/p-CdTe/Pt X-ray detectors

2013

Over the last decades, CdTe detectors are widely used for the development of room temperature X-ray and gamma ray spectrometers. Typically, high resolution CdTe detectors are fabricated with blocking contacts (indium, aluminum) ensuring low leakage currents and high electric field for optimum charge collection. As well known, time instability under bias voltage (termed as polarization) is the major drawback of CdTe diode detectors. Polarization phenomena cause a progressive degradation of the spectroscopic performance with time, due to hole trapping and detrapping from deep acceptors levels. In this work, we studied the polarization phenomenon on new Al/p-CdTe/Pt detectors, manufactured by …

A CdTe position sensitive spectrometer for hard X- and soft γ-ray polarimetry

2002

Coded Imager and Polarimeter for High Energy Radiation (CIPHER) is a hard X- and soft gamma- ray spectroscopic and polarimetric coded mask telescope based on an array of Cadmium telluride microspectrometers. The position sensitive detector (PSD) will be arranged in 4 modules of 32 x 32 crystals, each of 2 x 2 mm(2) cross-section and 10 mm thickness giving a total active area of about 160 cm(2), operating over a wide energy range (similar to10 keV to 1 MeV). Each PSD module is obtained by aligning 32 linear arrays of micro-detectors each also containing the integrated analog front end electronics on a thin ceramic layer. The CIPHER instrument will be proposed for a balloon experiment, both i…

THE LIMITING EFFICIENCY OF FOUR-BAND CELLS REVISITED

2014

The limiting theoretical efficiency of four-band solar cells is revisited. In previous work, researchers have looked at the theoretical efficiency of four band cells where the smallest of the three sub-band gaps is closest to the valence band and the largest closest to the conduction band. In this work, limits are calculated also for other possible band configurations. In multi-band cells, photon selectivity can be assured by adjusting the band widths. The present work shows that previous authors have put too rigid constraints on the band structure to achieve spectral selectivity. Relieving these constraints gives a considerably higher limiting efficiency for cells with band width restricti…

Electrical Characterization of CdTe pixel detectors with Al Schottky anode

2014

Abstract Pixelated Schottky Al/p-CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopic imaging, even though they suffer from bias-induced time instability (polarization). In this work, we present the results of the electrical characterization of a (4×4) pixelated Schottky Al/p-CdTe/Pt detector. Current–voltage ( I–V ) characteristics and current transients were investigated at different temperatures. The results show deep levels that play a dominant role in the charge transport mechanism. The conduction mechanism is dominated by the space charge limited current (SCLC) both under forward bias and at high reverse bias. Schottky barrier height of the Al/CdTe con…

Light trapping by plasmonic nanoparticles

2020

Abstract Metallic nanoparticles sustaining localized surface plasmon resonances are of great interest for enhancing light trapping in thin film photovoltaics. In this chapter, we explore the correlation between the structural and optical properties of self-assembled silver nanostructures fabricated by a solid-state dewetting process on various substrates relevant for silicon photovoltaics and later integrated into plasmonic back reflectors. Our study allows us to optimize the performance of nanostructures by identifying the fabrication conditions in which desirable circular and uniformly spaced nanoparticles are obtained. Second, we introduce a novel optoelectronic spectroscopic method that…