Simple indoline based donor–acceptor dye for high efficiency dye-sensitized solar cells

A simple metal-free donor–acceptor type sensitizer U01, bearing strong electron donor indoline-triphenylamine was synthesized for panchromatic sensitization of TiO₂ nanocrystalline film. Photovoltaic properties of U01 showed remarkably enhanced light harvesting due to the presence of strong electron donor and robust structure. The new U01 sensitized solar cell exhibited a photovoltaic performance: a short-circuit photocurrent density (J_sc) of 10.70 mA cm⁻², an open-circuit photovoltage (V_oc) of 0.758 V and a fill factor (FF) of 0.74, corresponding to an overall conversion efficiency of 6.01% under standard global AM 1.5 solar light condition. Our results suggest that indoline-triphenylamine based robust D–A molecular architecture is a highly promising class of panchromatic sensitizers for improvement of the performance of dye-sensitized solar cells (DSCs).     

HFCVD grown graphene like carbon–nickel nanocomposite thin film as effective counter electrode for dye sensitized solar cells

The two step processes of hot filament chemical vapor deposition (HFCVD) and DC sputtering were used to grow graphene like carbon (GLC)–nickel (Ni) nanocomposite thin film on fluorine-doped tin oxide (FTO) glass and applied as counter electrode (CE) for dye sensitized solar cells (DSSCs). The morphological and absorption properties revealed uniform GLC–Ni thin film with reasonable transmittance. The GLC–Ni thin film showed enhanced electrical conductivity as compared to FTO. The good electrocatalytic activity towards iodide ions in redox electrolyte was showed by the prepared GLC–Ni/FTO thin film electrode. The fabricated DSSC with GLC–Ni/FTO counter electrode (CE) presented relatively moderate solar-to-electrical conversion efficiency of ∼3.1% with high short-circuit current density (J_SC) of ∼10.03 mA/cm², open circuit voltage (V_OC) of ∼0.663 V with fill factor (FF) of ∼0.45, which might attribute to enhanced electrical conductivity and the electrocatalytic activity of GLC–Ni/FTO CE.     

Novel D-π-A dye sensitizers of polymeric metal complexes with phenylethyl or carbazole derivatives as donors for dye-sensitized solar cells: synthesis,characterization, and photovoltaic application

Four novel polymeric metal complexes containing D-π-A type structures were synthesized, characterized and applied as dye sensitizers in dye-sensitized solar cells (DSSCs). The alkoxy benzene or carbazole (CZ) derivative acts as an electron donor (D), C=C acts as π-bridge (π) and the 8-hydroxyquinoline derivative complex acts as electron acceptor. Bipyridine derivative was ancillary ligand as well as providing anchoring group. FT-IR, gel permeation chromatography, thermogravimetric analyses, differential scanning calorimetry, UV–Vis absorption spectroscopy, Elemental analysis, cyclic voltammetry, J-V curves and input photon to converted current efficiency plots were introduced to investigate the four dyes. These dyes exhibit good thermal stability with 5 % weight loss at temperatures (T_d) of around 300 °C. For the DSSCs devices using dyes with CZ derivatives as electron D (P2, P4) exhibited higher power conversion efficiency (PCE) than that with alkoxy benzene (P1, P3). The DSSC based on P4 exhibited the highest PCE value of 2.42 % (J _sc  = 4.93 mA/cm², V _oc  = 0.73 V, FF = 67.2 %) under AM 1.5G solar irradiation. This indicates a new way to design dye sensitizers for DSSCs.     

Equiaxed–columnar stacked TCO films for efficient silicon heterojunction solar cells

Journal of Materials Science: Materials in Electronics - Zr, Ti and Ga-doped indium oxide (ITGZO) films with different structures were prepared by radio frequency (RF) magnetron sputtering method....     

Nanoimprinted semiconducting polymer films with 50 nm features and their application to organic heterojunction solar cells

Nanoimprint lithography is used to directly pattern the conjugated polymer semiconductor poly(3-hexylthiophene) (P3HT). We obtain trenches with aspect ratios up to 2 and feature sizes as small as 50?nm in this polymer. The application to organic solar cells is shown by creating an interpenetrated donor-acceptor interface, based on P3HT and N,N'-ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C(13)), deposited from the vapor phase to reduce shadow effects. A planarizing layer of spin-coated zinc oxide (ZnO) nanoparticles is used to reduce the roughness of the layer stack. The response of the photovoltaic devices follows the increased interface area, up to a 2.5-fold enhancement.     

Semiconductor based photoelectrochemical cells for solar energy conversion—An overview

An overview of the semiconductor based photoelectrochemical (pec) cells for solar energy conversion is presented.pec cells are of two types: photoelectrolysis cells and photovoltaic cells. The principles involved, electrode and electrode/electrolyte interface characteristics, experimental methods of investigation and energy conversion efficiency are discussed in detail. Up-to-date data on variouspec cells are also presented and discussed.     

Solution-processed MoO₃ thin films as a hole-injection layer for organic solar cells

We report on a sol-gel-based technique to fabricate MoO(3) thin films as a hole-injection layer for solution-processed or thermally evaporated organic solar cells. The solution-processed MoO(3) (sMoO(3)) films are demonstrated to have equal performance to hole-injection layers composed of either PEDOT:PSS or thermally evaporated MoO(3) (eMoO(3)), and the annealing temperature at which the sol-gel layer begins to work is consistent with the thermodynamic analysis of the process. Finally, the shelf lifetime of devices made with the sMoO(3) is similar to equivalent devices prepared with a eMoO(3) hole-injection layer.     

Optimization of sensitized perovskite solar cells with Zn–Cu–In–Se quantum dots to increase quantum efficiency

Journal of Materials Science: Materials in Electronics - Perovskite solar cells are efficient units in systems with modern renewable energy sources. Increasing the efficiency of solar cells is...     

Synthesis and characterization of Y-shape electron donor–acceptor type organic dyes for dye-sensitized solar cells

Three Y-shape organic dyes, (Z)-3-(5-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)thiophen-2-yl)-2-cyanoacrylic acid (OD-1), (Z)-3-(5′-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)-2,2′-bithiophen-5-yl)-2-cyanoacrylic acid (OD-2) and (Z)-3-(5′-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)-3,4′-4″-trithiophenyl-5-yl)-2-cyanoacrylic acid (OD-3) were synthesized and used as sensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The introduction of the bis(carbazolylstyryl) units as an electron donor group and oligothiophene units as a both electron donors and π-spacers increased the conjugation length of the sensitizers and thus improved their molar absorption coefficient and light harvesting efficiency. DSSCs with the configuration of SnO₂:F/TiO₂/organic dye/liquid electrolyte/Pt devices were fabricated using these OD-1, OD-2 and OD-3 as a sensitizers. Among the devices, the DSSC composed of OD-3 exhibited highest power conversion efficiency of 3.03% under AM1.5G (100 mW cm⁻²).     

A solution-processable D–A–D small molecule based on isoindigo for organic solar cells

A new linear D–A–D organic small molecule (M1), with triphenylamine as electron donor (D) unit and isoindigo (ID) as electron acceptor (A) unit, was synthesized by Stille coupling reactions. It exhibits broad and strong absorption (300–700 nm), a relatively low HOMO energy level (?5.30 eV), low band gap (1.69 eV), and moderate hole mobility (2.49×10^?4 cm²/Vs). Solution-processed small molecule bulk-heterojunction solar cells based on M1: PC₆₁BM (1:3, w/w) blend film exhibits a power conversion efficiency of 0.84 % with an open-circuit voltage (V _oc) of 0.78 V, under the illumination of AM1.5, 100 mW/cm².     

One-step synthesis of CdS sensitized TiO₂ photoanodes for quantum dot-sensitized solar cells by microwave assisted chemical bath deposition method

Sensitized-type solar cells based on TiO? photoanodes and CdS quantum dots (QDs) as sensitizers have been studied. CdS QDs are grown on TiO? films, utilizing one-step microwave assisted chemical bath deposition (MACBD) method. This method allows a facile and rapid deposition and integration between CdS QDs and TiO? films. The photovoltaic performances of the cells fabricated using CdS precursor solutions with different concentrations are investigated. The results show that the cell based on MACBD deposited TiO?/CdS electrode achieves a maximum short circuit current density of 7.20 mAcm?2 and power conversion efficiency of 1.18 % at one sun (AM 1.5G, 100 mW cm?2), which is comparable to the ones prepared using conventional techniques.     

Synthesis of novel counter electrode by combination of mesoporous–macroporous CZTS films for enhanced performance of quantum-dots sensitized solar cells

This present study aims to manifest the potential of CZTS films as a low-cost counter electrode (CE) in quantum-dots sensitized solar cells (QDSSCs). Hitherto, numerous researchers have reported the application of either CZTS nano particles or films as a counter electrode in dye sensitized solar cells. However, its use in QDSSCs is scarcely reported. Herein, CdS quantum-dots sensitized ZnO film is used as photoanode. In the beginning, as a counter electrode, two different CZTS films (mesoporous and macroporous) are prepared using two different deposition techniques (spray pyrolysis and spin coating, respectively). For the meso-CZTS film, high V_OC and FF are observed, whereas, for the macro-CZTS film, high J_SC is observed. Hence, to take the advantage of both, subsequently, a film (meso–macro-CZTS) comprising mesoporous film upon the macroporous film is prepared and applied as CE. For the meso–macro-CZTS, substantial enhancement in power conversion efficiency (PCE) is observed. Additionally, to compare the results with commonly reported CEs (SnS/FTO and Pt–FTO) are also applied in QDSSCs. Moreover, to improve the PCE combination of these CEs along with meso–macro-CZTS, for instance, CZTS/SnS/FTO and CZTS/Pt–FTO are also applied as CE. The highest efficiency of 4.34% is achieved with CZTS/Pt–FTO.     

Growth of single-crystalline rutile TiO2 nanorods on fluorine-doped tin oxide glass for organic–inorganic hybrid solar cells

Single-crystalline TiO₂ nanorods (TiO₂ NRs) are grown directly on FTO substrates by hydrothermal methods. The diameters and lengths of TiO₂ NRs are easily controlled by growth conditions. When used in hybrid solar cells, TiO₂ NRs function as the continuous pathway for fast electron transport to charge collecting electrode, demonstrating a high power conversion efficiency (PCE) of 3.21% with 140?nm long TiO₂ NRs. The bilayer polymer coating are introduced into 500?nm long TiO₂ NRs to reduce the surface roughness, resulting in the improved contact between the polymer blend and silver electrode and an enhanced PCE from 2.70 to 3.07%.     

Preparation and characterization of (100 − x) TiO<Subscript>2</Subscript> + (x)ZnO nanocomposites for dye-sensitized solar cells using <Emphasis Type="Italic">Beta vulgaris</Emphasis> and <Emphasis Type="Italic">Syzygium cumini</Emphasis> natural dye extract

The present paper attempts to report the preparation of TiO₂–ZnO nanocomposite photoanode materials for dye-sensitized solar cells (DSSC) and analyse the efficiency of DSSC with natural dyes. The structural and optical characteristics of the composites were studied by transmission electron microscopy, X-ray diffraction, field effective scanning electron microscopy, energy dispersive spectrometry, photoluminescence and absorption spectroscopy. The synthesized nanocomposites formed on FTO substrates are applied as photoanode in a dye-sensitized solar cell (DSC). The natural dyes extracted from Beta vulgaris (Beetroot) and Syzygium cumini (black plum) were used in the fabrication of DSSC. The solar cells’ photovoltaic performance in terms of short-circuit current, open circuit voltage, fill factor and energy conversion efficiency was tested with photocurrent density–voltage measurements. The evolution of the solar cells parameters is explored as a function of the photoanode and type of dye used in DSSC fabrication.The obtained results show that the efficiency of DSSC significantly changes with the addition of ZnO to TiO_2, while the Beta vulgaris dye has evidently shown higher photo sensitized performance compared to Syzygium cumini in the preparation of DSSC.