Lead sulfide nanocrystal: conducting polymer solar cells (original) (raw)
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Photovoltaic and optical properties of a polymer-PbS nanocomposite
Photovoltaic and optical properties of a polymer-PbS nanoparticles in polyvinyl alcohol (PVA) films and the effect of annealing in air at various temperatures on these properties are studied in this work. In the range of 1.0 to 3.7 eV, absorption spectra of PbS nanocomposite films are correctly fitted by five Gaussian bands peaking at 1.5, 1.84, 2.41, 3.06, and 3.58 eV. A characteristic feature of the films is the presence of green and blue luminescence with intensity maxima at 2.25 and 3.02 eV, respectively. The luminescence intensity strongly depends on the excitation energy and the annealing temperature in air. The highest intensity of the green luminescence is observed under the excitation with 2.35 eV radiation, whereas the intensity of the blue luminescence peaks under 3.46 eV excitation. After annealing at 370 K, the intensity of the green luminescence decreases a few times whereas the intensity of the blue emission increases. The photovoltaic sensitivity of the PbS nanocompo...
PbS nanocrystals in hybrid systems for solar cell applications
physica status solidi (a), 2014
Many research efforts are focused toward significant improvements of polymeric solar cells efficiency, energy harvesting range, time, and environmental stability. Particular attention is given to hybrid organic/inorganic composites constituted of polymer/lead chalcogenides (PbS and PbSe) nanocrystals (NCs) to extend the spectral sensitivity of cells to near-infrared wavelengths. In this work we report the synthesis and characterization of PbS nanocrystals with absorption edge at 984 nm. The nanocrystals have a cubic crystal structure and size of about 2 nm as found by X-ray diffraction analysis. They were combined with poly(3-hexylthiophene) (P3HT) polymer to obtain P3HT:PbS blends with different PbS loadings. A postdeposition ligand exchange on PbS NCs by 1,2-ethanedithiol (EDT) allowed a better interaction between polymer and nanocrystals as showed by fluorescence measurements. The P3HT:PbS blends were deposited and treated by a layer by layer spin coating process and used as active layer in solar cells having structure glass/ITO/PEDOT:PSS/blend/Al. The major result obtained for this hybrid system is an increase of PCE by about two orders of magnitude with respect to analogous reported cells where a post-deposition ligand exchange was performed.
Applied Physics Letters, 2005
We report a comparison of photoconductive performance of PbS nanocrystal/polymer composite devices containing either oleic acid-capped or octylamine capped nanocrystals ͑NCs͒. The octylamine-capped NCs allow over two orders of magnitude more photocurrent under −1 V bias; they also show an infrared photovoltaic response, while devices using oleic acid-capped NCs do not. Further improvement in the photovoltaic performance of films made with octylamine-capped NCs occurs upon thermally annealing the composite layer at 220°C for 1 h. The procedure leads to a 200-fold increase in short circuit current, a 600-fold increase in maximum power output, and an order of magnitude faster response time.
Evolution of Long Range Bandgap Tunable Lead Sulfide Nanocrystals with Photovoltaic Properties
The Journal of Physical Chemistry C, 2013
Monodispersed bandgap tunable lead sulfide nanocrystals ranging from 0.6 to 1.7 eV have been synthesized by adjusting the reaction temperature and growth time. An evolution from cuboctahedra to perfect cube takes place at higher reaction temperature with longer annealing time. The nanocrystals absorb light both in the visible and IR spectral range. Bandgap dependent photovoltaic studies reveal optimal device performance for a critical size nanocrystal with ∼1.2 eV bandgap revealing the role of optimum bandgap on the photovoltaic performance.
Hybrid materials of lead selenide nanocrystals (PbSe-NCs) and organic polymers were produced through a layer-by-layer (LBL) solution-based deposition technique. Polymer series comprises sulfonate-, carboxylate-, and pyridine-based polymers. Nonaqueous dispersions of oleate-capped PbSe-NCs with 2.4 or 2.8 nm diameter were used. Polymers and PbSe-NCs are alternately deposited on ITO-glass surfaces. PbSe-NCs layers in acetonitrile undergo a sharp and irreversible electroxidation process involving two electrons per PbSe unit and an irreversible reduction process due to reduction of a surface lead(II) shell, which involves 20% of the oxidation charge. The multilayer build-up, monitored by UV-vis spectroscopy and cyclic voltammetry, proceeds with a linear increase in the film absorbance and oxidation stripping charge with the number of adsorbed PbSe layers. FTIR analysis has shown that the layering polymers remove the oleate capping ligands completely. The semiconductor properties of these LBL films were evidenced by photoelectrolchemical and (photo)conduction analysis. Photoelectrochemical (oxygen reduction) and photoconductivity responses are stronger in pyridine-than in carboxylate-and sulfonate-based multilayers, suggesting the occurrence of an efficient trapping of the surface lead(II) shell by pyridine moieties. (4) Steckel, J. S.; Coe-Sullivan, S.; Bulovic, V.; Bawendi, M. Adv. Mater. 2003, 15, 1862. (5) Koleilat, G. I.; Levina, L.; Shukla, H.; Myrskog, S. H.; Hinds, S.; Pattantyus-Abraham, A. G.; Sargent, E. H. ACS Nano 2008, 2, 833.
Nanotechnology Reviews
In this study, a hydrothermal technique was used to synthesize lead sulfide (PbS) and silver (Ag)-doped PbS nanoparticles (NPs) at different concentrations of 20, 40, and 60% of Ag. The small lattice phase changes appeared due to the shifting of diffraction angle peaks toward higher 2θ for samples doped with PbS with increasing Ag content. The analysis of average crystallite size, phase structure, and lattice constant was observed under X-ray diffraction. The value of crystallite size, volume of the unit cell, and porosity (%) were found to increase with the increasing concentration of Ag NPs in PbS. The pure PbS crystallite size is small compared to Ag-doped PbS. The optical characteristics including absorption spectra of the prepared samples were investigated and confirmed by using scanning electron microscope and UV-Vis spectroscopy. The observation of the composition showed that higher doping concentrations of Ag lead to an increase in particle size. Absorption peaks in the UV-V...
PbS QUANTUM DOT-BASED HETROJUNCTION SOLAR CELLS
2014
This study investigates the influence of nanoparticles (NPs) size on their optical properties, and the effect of combination of lead sulfide (PbS) quantum dots (QDs), with n-type and p-type NPs, on the photogenerated charge carriers transport across the heterojunction solar cell structure. PbS QDs, of a range of sizes, were synthesized using a co-precipitation process. In this study, p-type NPs, which are poly [3,4-ethylenedioxythiophene] –poly [styrenesulfonate] (PEDOT: PSS), copper oxide (CuO) and graphene oxide (GO); and n-type NPs which are zinc oxide (ZnO), titanium dioxide (TiO2), cadmium sulfide (CdS) and bismuth sulfide (Bi2S3), were synthesized and characterized by SEM and UV-visible spectrophotometers. The NPs with enhanced optical properties were utilized in heterojunction solar cell structures via spin coating, chemical bath deposition and SILAR cycle methods. The morphology and the theoretical band energy diagram for each cell were examined. The photovoltaic performance...