Person

Nikolaos Vlachopoulos

Related publications (46)

Microbial bioelectrochemical cells for hydrogen generation based on irradiated semiconductor photoelectrodes

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Fabian Fischer, Michele Morgante

In recent years, one of the most important challenges of the 21st century is to satisfy the ever-increasing world's energy demand. Many efforts are being undertaken to find alternative renewable energy sources, which ideally should outcompete fossil fuel u ...

IOP PUBLISHING LTD2021

A molecular photosensitizer achieves a Voc of 1.24 V enabling highly efficient and stable dye-sensitized solar cells with copper(II/I)-based electrolyte

Shaik Mohammed Zakeeruddin, Jacques-Edouard Moser, Nikolaos Vlachopoulos, Felix Thomas Eickemeyer, Ulf Anders Hagfeldt, Yiming Cao, Etienne Christophe Socie, Marko Stojanovic, Yameng Ren, Dan Zhang

To develop photosensitizers with high open-circuit photovoltage (Voc) is a crucial strategy to enhance the power conversion efficiency (PCE) of co-sensitized solar cells. Here, we show a judiciously tailored organic photosensitizer, coded MS5, featuring th ...

2021

Effect of TiO2 Photoanodes Morphology and Dye Structure on Dye-Regeneration Kinetics Investigated by Scanning Electrochemical Microscopy

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Kazuteru Nonomura, Gunther Wittstock

The dye regeneration in dye-sensitized solar cells (DSSCs) is improved by optimizing the charge separation at the level of the sensitized semiconductor treatment of the mesoporous electrode by TiCl4 that passivates the surface for back electron transfer re ...

2020

Toward an alternative approach for the preparation of low-temperature titanium dioxide blocking underlayers for perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Kazuteru Nonomura, Lichen Zhao, Su Htike Aung

The anodic electrodeposition method is investigated as an alternative technique for the preparation of a titanium oxide (TiO2) blocking underlayer (UL) for perovskite solar cells (PSCs). Extremely thin Ti-IV-based films are grown from aqueous acidic titani ...

ROYAL SOC CHEMISTRY2019

Electrochemically polymerized poly (3, 4-phenylenedioxythiophene) as efficient and transparent counter electrode for dye sensitized solar cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Lin Yang, Jiahuan Zhang, Yan Hao

A new conducting polymer poly (3, 4-phenylenedioxythiophene) is synthesized by the electrochemical polymerization technique with different solvents. We find that solvents used in electrochemical polymerization play important roles for the catalytic activit ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Diverging surface reactions at TiO2- or ZnO-based photoanodes in dye-sensitized solar cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Kazuteru Nonomura, Gunther Wittstock

Fast recombination of electrons from semiconductors with the oxidized redox species in the electrolyte represents a major bottleneck in the improvement of ZnO-based dye-sensitized solar cells (DSSCs). While processes at the semiconductor-electrolyte interf ...

ROYAL SOC CHEMISTRY2019

Metal Coordination Complexes as Redox Mediators in Regenerative Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Yasemin Saygili, Marko Stojanovic, Natalie Flores Diaz

Dye-sensitized solar cells (DSSCs) have attracted a substantial interest in the last 30 years for the conversion of solar power to electricity. An important component is the redox mediator effecting the transport of charge between the photoelectrode and th ...

2019

Blocking the Charge Recombination with Diiodide Radicals by TiO2 Compact Layer in Dye-Sensitized Solar Cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Kazuteru Nonomura

The addition of a compact titanium dioxide (TiO2) layer between the fluorine-doped tin oxide (FTO) coated glass substrate and the mesoporous TiO2 layer in the dye-sensitized solar cell (DSC) based on the iodide/triiodide redox couple (I-/I-3(-)) is known t ...

ELECTROCHEMICAL SOC INC2019

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

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

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