Publications by Michael Graetzel

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Efficient dye-sensitized solar cells are based on highly diffusive mesoscopic layers that render these devices opaque and unsuitable for ultrafast transient absorption spectroscopy measurements in transmission mode. We developed a novel sub-200 femtosecond time-resolved diffuse reflectance spectroscopy scheme combined with potentiostatic control to study various solar cells in fully operational condition. We studied performance optimized devices based on liquid redox electrolytes and opaque TiO2 films, as w

We achieve a 20-58 nm (610-1890 cm (1)) blue-shift of the phosphorescence maximum of iridium(III) complexes (CN)(2)Ir(NN) of 1,10-phenanthrolines (NN) by modifying the cyclometalating 2-phenylpyridine ligand (CN = ppy) with an electron-w ...

Perovskite solar cells (PSCs) have emerged as a potential candidate for high efficiency low-cost photovoltaic technology. However, the intrinsic and interfacial responses of PSCs under photo and bias-induced degradation and recovery have not been clearly u ...

Binary melts of S-ethyltetrahydrothiophenium iodide and dicyanoamide (or tricyanomethide) have been employed for dye-sensitized solar cells with high power conversion efficiencies up to 6.9% under the illumination of AM 1.5G full sunlight. We have further ...

Organic sensitizers comprising of donor, electron-conducting, and anchoring groups are designed and developed for dye-sensitized solar cell applications. A solar cell employing 3-(5'-{4-[bis-(4-hexyloxy-phenyl)-amino]-phenyl}-[2,2']bithiophenyl-5-yl)-2-cya ...

Dye sensitized solar cells were assembled employing a mixture of anthocyanins extracted from red ceibo's flowers. At the literature different extraction procedures are reported to extract anthocyanins from natural products and sensitize the cells. In order ...

Synthesis of the Ru(dcbpy)(2)(OQN) complex is reported in which dcbpy and OQN(-) are the bidentate 4,4'-dicarboxy-2,2'-bipyridyl and 8-oxyquinolate ligands, respectively. Spectroscopic, electrochemical, and theoretical analyses are indicative of exten ...

Colloidal quantum dot (CQD) photovoltaics combine low-cost solution processibility with quantum size-effect tunability to match absorption with the solar spectrum. Recent advances in CQD photovoltaics have led to 3.6% AM1.5 solar power conversion efficiencies. Here we report CQD photovoltaic devices on transparent conductive oxides and show that our devices rely on the establishment of a depletion region for field-driven charge transport and separation. The resultant depleted-heterojunction solar cells prov

A dimeric composition of the formula: wherein L', L'', L''', and L'''' are each a bidentate ligand having at least one functional substituent, the ligand selected from bipyridine, phenanthroline, 2-phenylpyridine, bipyrimidine, and bipyrazyl and the functional substituent selected from carboxylic acid, ester, amide, halogenide, anhydride, acyl ketone, alkyl ketone, acid chloride, sulfonic acid, phosphonic acid, and nitro and nitroso groups. An electrochemical oxidation process for the production of

We elaborated a new electrolyte composition, based on butyronitrile solvent, that exhibits low volatility for use in dye-sensitized solar cells. The strong point of this new class of electrolyte is that it combines high efficiency and excellent stability p ...

Surface passivation treatment is a widely used strategy to resolve trap-mediated nonradiative recombination toward high-efficiency metal-halide perovskite photovoltaics. However, a lack of passivation with mixture treatment has been investigated, as well a ...

The present invention relates to a method for producing a solid solar cells, comprising the steps of providing a hole collector layer, applying a conductive layer onto the hole collector layer, applying an electron blocking layer onto the conductive layer, ...

Post-treatment of mesoporous titanium dioxide films by TiCl4 solutions is commonly applied during the fabrication of solid-state dye-sensitized solar cells (ssDSCs), as this operation markedly improves the performance of the photovoltaic device. The effect ...

We report on the optimization of the interfacial properties of titania in mesoscopic CH3NH3PbI3 solar cells. Modification of the mesoporous TiO2 film by TiCl4 treatment substantially reduced the surface traps, as is evident from the sharpness of the absorp ...

Host-guest complexation offers a promising approach for mitigating surface defects in perovskite solar cells (PSCs). Crown ethers are the most widely used macrocyclic hosts for complexing perovskite surfaces, yet their supramolecular interactions and funct ...

The phase diagram of the redox active ionic liquid 1-methyl-3-propylimidazolium iodide (PMII) is examined as a function of temperature and iodine concentration. Beyond a threshold concentration of 3.9 M, the formation of higher polyiodides gives rise to a ...

Metal halide to perovskite phase conversion is a facile approach for synthesizing high-quality perovskite semiconductors for optoelectronic applications. Here, these reactions are investigated at the nanoscale via in-situ x-ray scattering, revealing links ...

Perovskite solar cells (PSCs) with efficiencies greater than 20% have been realized only with expensive organic hole-transporting materials. We demonstrate PSCs that achieve stabilized efficiencies exceeding 20% with copper(I) thiocyanate (CuSCN) as the ho ...

Sb2S3-sensitized mesoporous-TiO2 solar cells using several conjugated polymers as hole-transporting materials (HTMs) are fabricated. We found that the cell performance was strongly cc rrelated with the chemical interaction at the interface of Sb2S3 as sens ...

A cyclic tetranuclear cyclometallated iridium(III) complex using cyanide anions as bridging ligands and displaying a tetrahedrally distorted square geometry has been obtained with high yield; photo- and electrochemical characterizations show that most inte ...

Michael Graetzel

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Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

How to blue-shift phosphorescence color of iridium(III) complexes

Intrinsic and interfacial kinetics of perovskite solar cells under photo and bias-induced degradation and recovery

Tetrahydrothiophenium-based ionic liquids for high efficiency dye-sensitized solar cells

Highly Efficient Organic Sensitizers for Solid-State Dye-Sensitized Solar Cells

A cockspur for the DSS cells: Erythrina crista-galli sensitizers

Evaluation of a Ruthenium Oxyquinolate Architecture for Dye-Sensitized Solar Cells

RECTRATED: Advances in colloidal quantum dot solar cells: The depleted-heterojunction device

Molecular water oxidation catalyst

Butyronitrile-based electrolyte for dye-sensitized solar cells

Surface Reconstruction Engineering with Synergistic Effect of Mixed‐Salt Passivation Treatment toward Efficient and Stable Perovskite Solar Cells

Inverted solar cell and process for producing the same

Effect of Posttreatment of Titania Mesoscopic Films by TiCl4 in Solid- State Dye-Sensitized Solar Cells: A Time-Resolved Spectroscopy Study

Impact of a Mesoporous Titania-Perovskite Interface on the Performance of Hybrid Organic-Inorganic Perovskite Solar Cells

Tailored Supramolecular Interactions in Host–Guest Complexation for Efficient and Stable Perovskite Solar Cells and Modules

Conduction Through Viscoelastic Phase in a Redox-Active Ionic Liquid at Reduced Temperatures

Kinetics and energetics of metal halide perovskite conversion reactions at the nanoscale

Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%

Toward Interaction of Sensitizer and Functional Moieties in Hole-Transporting Materials for Efficient Semiconductor-Sensitized Solar Cells

A bright tetranuclear iridium(III) complex