We report an efficient nonplatinized flexible counter electrode for dye-sensitized solar cells. In combination with a solvent-free ionic liquid electrolyte, we have demonstrated a ∼6.5% cell with an ...amphiphilic ruthenium polypyridyl photosensitizer showing excellent stability measured under prolonged light soaking at 60 °C. Compared to the Pt deposited PEN film, the CoS deposited PEN film shows higher electrocatalytic activity for the reduction of triiodide. This is expected to have an important practical consequence on the production of flexible low-cost and lightweight thin film DSC devices based on the plastic matrix.
A high molar extinction coefficient heteroleptic ruthenium complex, incorporating an electron-rich hexylthio-terminal chain, has been synthesized and demonstrated as an efficient sensitizer for ...dye-sensitized solar cells. With this new sensitizer excellent power conversion efficiency is 11.5% and 4.7% obtained under an irradiation of full sunlight (air mass 1.5 global) in combination with a volatility electrolyte and solid state hole transporting material, respectively. The devices with low volatility electrolyte showed good stability under visible-light soaking at 60 °C during 1000 h of accelerated tests.
High-efficiency flexible dye-sensitized solar cells were fabricated with a Ti-metal foil substrate for photo anode and using a Pt-electrodeposited counter electrode on ITO/polyethylene naphthalate ...(ITO/PEN); these devices were characterized by incident photon-to-current efficiency (IPCE), optical transmittance and electrical impedance spectroscopy.
Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic ...devices. We report on the use of a new class of Co(III) complexes as p-type dopants for triarylamine-based hole conductors such as spiro-MeOTAD and their application in solid-state dye-sensitized solar cells (ssDSCs). We show that the proposed compounds fulfill the requirements for this application and that the discussed strategy is promising for tuning the conductivity of spiro-MeOTAD in ssDSCs, without having to rely on the commonly employed photo-doping. By using a recently developed high molar extinction coefficient organic D-π-A sensitizer and p-doped spiro-MeOTAD as hole conductor, we achieved a record power conversion efficiency of 7.2%, measured under standard solar conditions (AM1.5G, 100 mW cm–2). We expect these promising new dopants to find widespread applications in organic electronics in general and photovoltaics in particular.
We designed and synthesized two new zinc porphyrin dyes for dye‐sensitized solar cells (DSCs). Subtle molecular structural variation in the dyes significantly influenced the performance of the DSC ...devices. By utilizing these dyes in combination with a cobalt‐based redox electrolyte using a photoanode made of mesoporous TiO2, we achieved a power conversion efficiency (PCE) of up to 12.0 % under AM 1.5 G (100 mW cm−2) simulated solar light. Moreover, we obtained a high PCE of 6.4 % for solid‐state dye‐sensitized solar cells by using 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene as a hole‐transporting material.
Dying to live: Subtle molecular structural variations in two zinc porphyrin dyes significantly influence the performance of dye‐sensitized solar cell devices. By utilizing the dyes in combination with a cobalt‐based redox electrolyte, a high power conversion efficiency (PCE) under simulated solar light is achieved. When using spiro‐OMeTAD as the hole‐transporting material in solid‐state solar cells, the highest PCE for such a device until now is observed.
The high‐molar‐extinction‐coefficient heteroleptic ruthenium dye, cis‐Ru (4,4′‐bis(5‐octylthieno3,2‐b thiophen‐2‐yl)‐2,2′‐bipyridine) (4,4′‐dicarboxyl‐2,2′‐bipyridine) (NCS)2, exhibits an AM 1.5 ...solar (100 mW cm−2)‐to‐electric power‐conversion efficiency of 4.6% in a solid‐state dye‐sensitized solar cell (SSDSC) with 2,2′, 7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)9,9′‐spirobifluorene (spiro‐MeOTAD) as the organic hole‐transporting material. These SSDSC devices exhibit good durability during accelerated tests under visible‐light soaking for 1000 h at 60 °C. This demonstration elucidates a class of photovoltaic devices with potential for stable and low‐cost power generation. The electron recombination dynamics and charge collection that take place at the dye‐sensitized heterojunction are studied by means of impedance and transient photovoltage decay techniques.
Solid‐state nanocrystalline dye‐sensitized solar cells based on an organic hole‐transporting material and a new high‐molar‐extinction‐coefficient sensitizer achieve 4.6% power conversion efficiency under full sunlight intensity (see graph), showing good durability in accelerated tests. The influence of the long‐term light soaking on the thin‐film photovoltaic figures of merit are investigated in detail by electrochemical impedance and photovoltage transient techniques.
A new series of panchromatic ruthenium(II) sensitizers derived from carboxylated terpyridyl complexes of tris-thiocyanato Ru(II) have been developed. Black dye containing different degrees of ...protonation {(C2H5)3NH}Ru(H3tcterpy)(NCS)3 1, {(C4H9)4N}2Ru(H2tcterpy)(NCS)3 2, {(C4H9)4N}3Ru(Htcterpy)(NCS)3 3, and {(C4H9)4N}4Ru(tcterpy)(NCS)3 4 (tcterpy = 4,4‘,4‘ ‘-tricarboxy-2,2‘:6‘,2‘ ‘-terpyridine) have been synthesized and fully characterized by UV−vis, emission, IR, Raman, NMR, cyclic voltammetry, and X-ray diffraction studies. The crystal structure of complex 2 confirms the presence of a RuIIN6 central core derived from the terpyridine ligand and three N-bonded thiocyanates. Intermolecular H-bonding between carboxylates on neighboring terpyridines gives rise to 2-D H-bonded arrays. The absorption and emission maxima of the black dye show a bathochromic shift with decreasing pH and exhibit pH-dependent excited-state lifetimes. The red-shift of the emission maxima is due to better π-acceptor properties of the acid form that lowers the energy of the CT excited state. The low-energy metal-to-ligand charge-transfer absorption band showed marked solvatochromism due to the presence of thiocyanate ligands. The Ru(II)/(III) oxidation potential of the black dye and the ligand-based reduction potential shifted cathodically with decreasing number of protons and showed more reversible character. The adsorption of complex 3 from methoxyacetonitrile solution onto transparent TiO2 films was interpreted by a Langmuir isotherm yielding an adsorption equilibrium constant, K ads, of (1.0 ± 0.3) × 105 Μ-1. The amount of dye adsorbed at monolayer saturation was (n α = 6.9 ± 0.3) × 10-8 mol/mg of TiO2, which is around 30% less than that of the cis-di(thiocyanato)bis(2,2‘-bipyridyl-4,4‘-dicarboxylate)ruthenium(II) complex. The black dye, when anchored to nanocrystalline TiO2 films achieves very efficient sensitization over the whole visible range extending into the near-IR region up to 920 nm, yielding over 80% incident photon-to-current efficiencies (IPCE). Solar cells containing the black dye were subjected to analysis by a photovoltaic calibration laboratory (NREL, U.S.A.) to determine their solar-to-electric conversion efficiency under standard AM 1.5 sunlight. A short circuit photocurrent density obtained was 20.5 mA/cm2, and the open circuit voltage was 0.72 V corresponding to an overall conversion efficiency of 10.4%.
The high molar absorption coefficient organic D-π-A dye C220 exhibits more than 6% certified electric power conversion efficiency at AM 1.5G solar irradiation (100 mW cm−2) in a solid-state ...dye-sensitized solar cell using 2,2′,7,7′-tetrakis(N,N-dimethoxyphenylamine)-9,9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This contributes to a new record (6.08% by NREL) for this type of sensitized heterojunction photovoltaic device. Efficient charge generation is proved by incident photon-to-current conversion efficiency spectra. Transient photovoltage and photocurrent decay measurements showed that the enhanced performance achieved with C220 partially stems from the high charge collection efficiency over a wide potential range.
A high molar extinction coefficient charge transfer ruthenium sensitizer Ru(4,-carboxylic acid-4′-carboxylate-2,2′-bipyridine)(4,4′-di-(2-(3,6-dimethoxyphenyl)ethenyl)-2,2′-bipyridine)(NCS)
2 ...anchored onto a nanocrystalline TiO
2 films achieve very efficient sensitization in the visible region yielding under AM 1.5 sunlight a short-circuit photocurrent density of 18.84
mA/cm
2, the open-circuit voltage was 783
mV and a fill factor of 0.73, corresponding to an overall conversion efficiency of 10.82%.
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A high molar extinction coefficient charge transfer sensitizer tetrabutylammonium Ru(4,-carboxylic acid-4′-carboxylate-2,2′-bipyridine)(4,4′-di-(2-(3,6-dimethoxyphenyl)ethenyl)-2,2′-bipyridine)(NCS)
2, is developed which upon anchoring onto nanocrystalline TiO
2 films exhibit superior power conversion efficiency compared to the standard sensitizer bistetrabutylammonium
cis-dithiocyanatobis(4,4′-dicarboxylic acid-2,2′-bipyridine)ruthenium(II) (N719). The new sensitizer anchored TiO
2 films harvest visible light very efficiently over a large spectral range and produce a short-circuit photocurrent density of 18.84
mA/cm
2, open-circuit voltage 783
mV and fill factor 0.73, resulting remarkable solar-to-electric energy conversion efficiency (
η) 10.82, under Air Mass (AM) 1.5 sunlight. The Time Dependent Density Functional Theory (TDDFT) excited state calculations of the new sensitizer show that the first three HOMOs have ruthenium t
2g character with sizable contribution coming from the NCS ligands and the π-bonding orbitals of the 4,4′-di-(2-(3,6-dimethoxyphenyl)ethenyl)-2,2′-bipyridine. The LUMO is a π
* orbital localized on the 4,4′-dicarboxylic acid-2,2′-bipyridine ligand.
The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS)
2, exhibits ...certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100
mW
cm
−2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9,9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation.
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