Visible absorption and photocurrent spectra of epitaxially deposited phthalocyanine thin films: interpretation of exciton coupling effects

In this study, we have investigated the surface analysis and optoelectronic properties on the synthesis of N-CNT/TiO2 composites thin films, using sol gel method for a dye synthetized solar cell (DSSC) which is found to be simple and economical route. The titanium dioxide based solar cells are an exciting photovoltaic candidate; they are promising for the realization of large area devices. That can be synthetized by room temperature solution processing, with high photoactive performance. In the present work, we stated comparable efficiencies by directing our investigation on obtaining Sol Gel thin films based on N-CNT/TiO2, by dispersing nitrogen (N) doped carbon nanotubes (N-CNTs) powders in titanium tetraisopropoxyde (TTIP). The samples were assessed in terms of optical properties, using UV—visible absorption spectroscopic techniques. After careful analysis of the results, we have concluded that the mentioned route is good and more efficient in terms of optoelectronic properties. The gap of “the neat” 0.00w% N-CNT/TiO2 is of 3eV, which is in a good agreement with similar gap of semiconductors. The incorporated “w%NCNTs” led to diminishing the Eg with increasing N-CNTs amount. These consequences are very encouraging for optoelectronic field.

Download Full-text

Plasmon — exciton coupling effects in light absorption and scattering by metal/J-aggregate bilayer nanoparticles

Quantum Electronics ◽

10.1070/qe2012v042n08abeh014833 ◽

2012 ◽

Vol 42 (8) ◽

pp. 701-713 ◽

Cited By ~ 25

Author(s):

Vladimir S Lebedev ◽

A S Medvedev

Keyword(s):

Light Absorption ◽

Coupling Effects ◽

Exciton Coupling

Download Full-text

Ultrastrong coupling effects in molecular cavity QED

Nanophotonics ◽

10.1515/nanoph-2019-0403 ◽

2020 ◽

Vol 9 (2) ◽

pp. 277-281 ◽

Cited By ~ 1

Author(s):

Jorge Calvo ◽

David Zueco ◽

Luis Martin-Moreno

Keyword(s):

Cavity Qed ◽

Molecular Vibrations ◽

Level System ◽

Coupling Effects ◽

Photon Interaction ◽

Exciton Coupling ◽

Energy Dynamics

AbstractThe spectrum and energy dynamics for a system that comprises a molecule interacting with a cavity photon is analyzed, taking into account the effect of both molecular vibrations and counter-rotating terms (CR) in the dipole Hamiltonian. The CR terms do not have a strong effect on the spectrum even for moderately large values of the exciton-photon interaction. However, it is shown that the polariton subspace is governed by an effective Quantum-Rabi Hamiltonian, where polaritons act as a two-level system and the phonons play the role of cavity photons. The effect of the CR terms is amplified in the dynamics: as the vibrations reduce the effective photon-exciton coupling, small Bloch-Siegert energy shifts can bring the system out of resonance.

Download Full-text

Modulation of the Visible Absorption and Reflection Profiles of ITO Nanocrystal Thin Films by Plasmon Excitation

ACS Photonics ◽

10.1021/acsphotonics.9b01825 ◽

2020 ◽

Vol 7 (5) ◽

pp. 1188-1196

Author(s):

Michelle A. Blemker ◽

Stephen L. Gibbs ◽

Emily K. Raulerson ◽

Delia J. Milliron ◽

Sean T. Roberts

Keyword(s):

Thin Films ◽

Plasmon Excitation ◽

Visible Absorption

Download Full-text

Epitaxy of (GaN)1−x(ZnO)x Solid-Solution Thin Films with Widely Tunable Chemical Composition and Strong Visible Absorption

Physical Review Applied ◽

10.1103/physrevapplied.10.044001 ◽

2018 ◽

Vol 10 (4) ◽

Cited By ~ 6

Author(s):

Chang Yang ◽

Yasushi Hirose ◽

Takuto Wakasugi ◽

Naoki Kashiwa ◽

Hiroki Kawai ◽

...

Keyword(s):

Thin Films ◽

Solid Solution ◽

Chemical Composition ◽

Visible Absorption

Download Full-text

Electrical Properties of Pulsed Laser Deposited ZnO Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.67.121 ◽

2009 ◽

Vol 67 ◽

pp. 121-125

Author(s):

Chattopadhyay Sourav ◽

Kumar Nath Tapan

Keyword(s):

Thin Films ◽

Surface Morphology ◽

Substrate Temperature ◽

Hall Mobility ◽

Pulsed Laser ◽

Deposition Process ◽

Zno Thin Films ◽

Zno Films ◽

Visible Absorption ◽

Substrate Temperatures

Epitaxial Single-crystal ZnO thin films have been grown on c-plane (0001) sapphire by Pulsed Laser Deposition process at different substrate temperatures (300 – 800 °C) with 10-1 mbar oxygen pressure. The thicknesses of the films have been varied by varying number of pulses with a repetition rate of 10 pulse/sec. It is found that the sheet resistivity of ZnO thin films grown on c-plane sapphires are in the order of 10-2 Ω-cm and it increases with increasing substrate temperatures and film thickness. The carrier concentrations and Hall mobility are found to be in the order of 1017 cm-3 and ~195 cm2/V-s, respectively. The Hall mobility slightly decreases with increase of substrate temperature and thickness of the films. It is also found that the ZnO films are structurally uniform and well oriented with perfect wurtzite structure with c/a ratio 5.1. We have also deposited non-epitaxial ZnO films on (100) p-Silicon substrates at the same conditions. From HR FE-SEM micrographs, surface morphology of ZnO films grown at lower substrate temperature are found to be uniform compared to the films grown at higher temperatures showing non-uniformity and misoriented wurtzite structures. However, the surface morphology of ZnO flims grown epitaxially on (0001) sapphire are found to be more uniform and it does not change much with growth temperature. The resistivity of the films grown on p-Silicon at higher temperatures is in the order of 103 Ω-cm whereas films grown at lower substrate temperatures show comparatively lower resistivities (~ 102 Ω-cm). From the recorded UV-Visible absorption spectrum the band gap of the film has been estimated to be 3.38 eV.

Download Full-text

Surface Modification of Aerosol-Assisted CVD Produced TiO2Thin Film for Dye Sensitised Solar Cell

International Journal of Photoenergy ◽

10.1155/2014/586707 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 15

Author(s):

SuPei Lim ◽

Nay Ming Huang ◽

Hong Ngee Lim ◽

M. Mazhar

Keyword(s):

Thin Films ◽

Solar Cell ◽

Conversion Efficiency ◽

Indium Tin Oxide ◽

Particle Deposition ◽

Chemical Vapour ◽

Photocurrent Density ◽

Potential Candidate ◽

Visible Absorption ◽

Ag Particle

We report a simple and convenient method for the preparation of Ag/TiO2thin films supported on indium tin oxide, which was achieved by sonochemical deposition of Ag+on aerosol-assisted chemical vapour deposited TiO2thin films. Posttreatment was performed on the film by immersion in HCl. The as-prepared composite film was characterised by X-ray diffraction, ultraviolet-visible absorption spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. The photoelectrochemical measurements andJ-Vcharacterisation showed approximately fivefold increase in photocurrent density generation and approximately sevenfold enhancement in dye sensitiser solar cell (DSSC) conversion efficiency, which was achieved after modification of the TiO2film with HCl posttreatment and Ag particle deposition. The improved photocurrent density of 933.30 μA/cm2, as well as DSSC power conversion efficiency of 3.63% with high stability, is an indication that the as-synthesised thin film is a potential candidate for solar energy conversion applications.

Download Full-text

Effect of Cu/In Ratio on Properties of CuInS2 Films Prepared by Ultrasonic Spray Pyrolysis Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.199-200.1936 ◽

2011 ◽

Vol 199-200 ◽

pp. 1936-1939

Author(s):

Xiao Zhang ◽

Hua Wang ◽

Ji Wen Xu ◽

Ling Yang ◽

Ming Fang Ren

Keyword(s):

Thin Films ◽

Spray Pyrolysis ◽

Ultrasonic Spray Pyrolysis ◽

Xrd Analysis ◽

Chalcopyrite Structure ◽

Spray Pyrolysis Method ◽

Visible Absorption ◽

Ultrasonic Spray ◽

Pyrolysis Method ◽

Ultrasonic Spray Pyrolysis Method

CuInS2 thin films were prepared on heated glass substrates by ultrasonic spray pyrolysis method. Structure, surface morphology and properties of films with different Cu/In ratios have been investigated. X-ray diffraction (XRD) analysis demonstrated that as-prepared CuInS2 thin films with chalcopyrite structure have a preferential orientation along the (112) direction. SEM study shows films are relatively dense and smooth, but the much bigger grains and the large coherent agglomerates appear in films (Cu/In>1.25) due to the appearance of phase Cu2S. CuInS2 thin film (Cu/In=1.25) has a strong visible absorption and its energy band gap comes up to 1.45eV.

Download Full-text