Ulf Anders Hagfeldt

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Related publications (575)

A tandem redox system with a cobalt complex and 2-azaadamantane-N-oxyl for fast dye regeneration and open circuit voltages exceeding 1 V

Shaik Mohammed Zakeeruddin, Jacques-Edouard Moser, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Heewon Bahng, Natalie Flores Diaz

A new tandem electrolyte composed of two redox pairs, the organic radical 2-azaadamantane-N-oxyl (AZ) and the well-known redox pair Co(bpy)(3) was investigated in dye sensitized solar cells. Importantly, an increase in V-OC was achieved using the ...

ROYAL SOC CHEMISTRY2019

Atomic Layer Deposition of ZnO on CuO Enables Selective and Efficient Electroreduction of Carbon Dioxide to Liquid Fuels

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jing Gao, Ulf Anders Hagfeldt, Jingshan Luo, Dan Ren, Zaiwei Wang, Linfeng Pan

Electrochemical reduction of carbon dioxide, if powered by renewable electricity, could serve as a sustainable technology for carbon recycling and energy storage. Among all the products, ethanol is an attractive liquid fuel. However, the maximum faradaic e ...

WILEY-V C H VERLAG GMBH2019

Molecular Engineering of Simple Metal-Free Organic Dyes Derived from Triphenylamine for Dye-Sensitized Solar Cell Applications

Michael Graetzel, Shaik Mohammed Zakeeruddin, Farzan Jazaeri, Yuhang Liu, Parnian Ferdowsi, Ulf Anders Hagfeldt, Yasemin Saygili

Two new metal-free organic sensitizers, L156 and L224, were designed, synthesized, and characterized for application in dye-sensitized solar cells (DSCs). The structures of the dyes contain a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4- ...

WILEY-V C H VERLAG GMBH2019

High electron-injection efficiency is important for further development of dye-sensitized solar cells (DSSCs). Different electron acceptors have different electron-injection capabilities, which affect device performance. Herein, the effects of two organic ...

WILEY-V C H VERLAG GMBH2019

Photoelectrochemical Cells Based on Dye Sensitization for Electricity and Fuel Production

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt

Dye-sensitized semiconductor oxide photoelectrodes in which light is absorbed by a monomolecular layer of dye chemisorbed on a porous oxide substrate have attracted considerable interest in the last 35 years, mainly for the conversion of sunlight to electr ...

SWISS CHEMICAL SOC2019

Towards Oxide Electronics: a Roadmap

Ulf Anders Hagfeldt, Francisco Sanchez, Mauro Fanciulli, Monica Marcela Lira Cantu, Brahim Dkhil

At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore's law is approaching the insurmountable barrier given by the ultimate atomic nature of ...

2019

Dye sensitized photoelectrolysis cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Sining Yun

To advance the progress of photoelectrolysis, various promising devices integrated with p- and n-type photocatalysts and dye sensitized photoelectrodes have been systematically studied. This review discusses, from theory to practice, an integration strateg ...

ROYAL SOC CHEMISTRY2019

Directly Photoexcited Oxides for Photoelectrochemical Water Splitting

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Linfeng Pan

Artificial photosynthesis promises to become a sustainable way to harvest solar energy and store it in chemical fuels by means of photoelectrochemical (PEC) cells. Although it is intriguing to shift the fossil-fuel-based economy to a renewable carbon-neutr ...

WILEY-V C H VERLAG GMBH2019

Crystal Orientation and Grain Size: Do They Determine Optoelectronic Properties of MAPbI(3) Perovskite?

Sandy Sanchez Alonso, Ulf Anders Hagfeldt, Michael Saliba

Growing large, oriented grains of perovskite often leads to efficient devices, but it is unclear if properties of the grains are responsible for the efficiency. Domains observed in SEM are commonly misidentified with crystallographic grains, but SEM images ...

2019

Effect of Coordination Sphere Geometry of Copper Redox Mediators on Regeneration and Recombination Behavior in Dye-Sensitized Solar Cell Applications

Shaik Mohammed Zakeeruddin, Jacques-Edouard Moser, Fabrizio Giordano, Ulf Anders Hagfeldt, Joël Teuscher, Yasemin Saygili, Marina Freitag, Marko Stojanovic, Jan Tiepelt

The recombination of injected electrons with oxidized redox species and regeneration behavior of copper redox mediators are investigated for four copper complexes, [Cu(dmby)2]2+/1+ (dmby = 6,6′-dimethyl-2,2′- bipyridine), [Cu(tmby)2]2+/1+ (tmby = 4,4′,6,6′ ...

2018

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