Publications by Kazuteru Nonomura

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

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

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

Zinc Phthalocyanine Conjugated Dimers as Efficient Dopant-Free Hole Transporting Materials in Perovskite Solar Cells

Ulf Anders Hagfeldt, Kazuteru Nonomura, Natalie Flores Diaz, Brian Irving Carlsen, Marco Alejandro Ruiz Preciado, Desiré Molina Alcaide, Bowen Yang, Felix Thomas Eickemeyer

Four ZnPc-dimers with 2,5-thienyl (ZnPc-th-ZnPc 1), 2,7-fluorenyl (ZnPc-flu-ZnPc 2), 3,6-bisthienylldiketopyrrolopyrrole (ZnPc-DPP-ZnPc 3) and 1,4-phenyl (ZnPc-p-ZnPc 4) bridges have been studied as dopant-free hole transporting materials (HTMs) in perovsk ...

WILEY-V C H VERLAG GMBH2020

Passivation Mechanism Exploiting Surface Dipoles Affords High-Performance Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Thomas La Grange, Paul Joseph Dyson, Ulf Anders Hagfeldt, Jun Ho Yum, Kevin Sivula, Kazuteru Nonomura, Erfan Shirzadi, Fatemeh Ansari

The employment of 2D perovskites is a promising approach to tackling the stability and voltage issues inherent in perovskite solar cells. It remains unclear, however, whether other perovskites with different dimensionalities have the same effect on efficie ...

AMER CHEMICAL SOC2020

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

Triarylamine-based hydrido-carboxylate rhenium(i) complexes as photosensitizers for dye-sensitized solar cells

Ulf Anders Hagfeldt, Thomas Moehl, Kazuteru Nonomura, Lorenzo Veronese

Two new dyes based on a dinuclear rhenium complex and (E)-3-(5-(4-(bis(2,4-dibutoxy-[1,1-biphenyl]-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (namely D35) have been investigated as sensitizers for dye sensitized solar cells (DSSCs). Two different ...

ROYAL SOC CHEMISTRY2019

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

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

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

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 Society of Chemistry2019

Interfacial Engineering of Metal Oxides for Highly Stable Halide Perovskite Solar Cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Wolfgang Richard Tress, Kazuteru Nonomura, Hui-Seon Kim, Zaiwei Wang, Monica Marcela Lira Cantu, Anna Morales Melgares, Haibing Xie

Oxides employed in halide perovskite solar cells (PSCs) have already demonstrated to deliver enhanced stability, low cost, and the ease of fabrication required for the commercialization of the technology. The most stable PSCs configuration, the carbon-base ...

WILEY2018

Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Yasemin Saygili, Kazuteru Nonomura, Enrico Polanski, Anna Eriksson, Jiahuan Zhang, Yan Hao

Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-pi-A dye (Dyenamo Blue), based on the diketopyrro ...

2016

Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ulf Anders Hagfeldt, Fabrizio Giordano, Kazuteru Nonomura, Antonio Abate

The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of ...

Nature Publishing Group2015

Facile route to freestanding CH3NH3PbI3 crystals using inverse solubility

Michael Graetzel, Ulf Anders Hagfeldt, Jeannette Medina Kadro, Kazuteru Nonomura

CH3NH3PbI3 was found to exhibit inverse solubility at high temperatures in gamma-butyrolactone. Making use of this unusual, so far unreported phenomenon, we present a facile method for the growth of freestanding crystals of CH3NH3PbI3 from solution without ...

Nature Publishing Group2015

Direct light-induced polymerization of cobalt-based redox shuttles: an ultrafast way towards stable dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Kazuteru Nonomura

The photopolymerization of Co(II)/Co(III) complexes for dye-sensitized solar cells (DSSCs) by means of a fast, inexpensive, in situ and inhibition-free process has been examined. We have succeeded in fabricating high-performance DSSCs able to retain a ligh ...

Royal Society of Chemistry2015

Nanoclay Gelation Approach toward Improved Dye-Sensitized Solar Cell Efficiencies: An Investigation of Charge Transport and Shift in the TiO2 Conduction Band

Michael Graetzel, Kazuteru Nonomura, Xiaoyan Wang

Nanoclay minerals play a promising role as additives in the liquid electrolyte to form a gel electrolyte for quasi-solid-state dye-sensitized solar cells, because of the high chemical stability, unique swelling capability, ion exchange capacity, and theolo ...

Amer Chemical Soc2013

Decoupling light absorption and charge transport properties in near IR-sensitized Fe2O3 regenerative cells

Michael Graetzel, Satvasheel Powar, Nripan Mathews, Kazuteru Nonomura

We report a regenerative iron oxide nanorod solar cell sensitized with squarine (SQ02) dye, which improves the overall light harvesting due to the dye's complementary absorption. The use of illumination sources which enabled selective excitation of Fe2O3 a ...

Royal Society of Chemistry2013

Influence of 4-tert-Butylpyridine in DSCs with Co-II/III Redox Mediator

Michael Graetzel, Ulf Anders Hagfeldt, Nripan Mathews, Kazuteru Nonomura

The effect of TBP on Co(II/III) redox electrolyte was examined. Photocurrent of the device can be limited in electrolyte with high TBP concentration due to its viscous nature. The higher amount of TBP in electrolyte increases the viscosity of electrolyte a ...

American Chemical Society2013

Photovoltage enhancement from cyanobiphenyl liquid crystals and 4-tert-butylpyridine in Co(II/III) mediated dye-sensitized solar cells

Michael Graetzel, Ulf Anders Hagfeldt, Nripan Mathews, Kazuteru Nonomura

Two cyanobiphenyl liquid crystals (LCs), 5CB (4-cyano-4'-pentylbiphenyl) and 8CB (4-cyano-4'-octylbiphenyl), are introduced as additives into Co(II/ III) electrolytes for dye-sensitized solar cells (DSCs). An electrolyte containing a combination of these L ...

Royal Society of Chemistry2013

A selective co-sensitization approach to increase photon conversion efficiency and electron lifetime in dye-sensitized solar cells

Michael Graetzel, Kazuteru Nonomura

Ruthenium-based C106 and organic D131 sensitizers have been judicially chosen for co-sensitization due to their complementary absorption properties and different molecular sizes. Co-sensitization yields a higher light-harvesting efficiency as well as bette ...

Royal Society of Chemistry2012