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Michael Graetzel

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Publications associées (1 223)

Unravel the Impact of Anchoring Groups on the Photovoltaic Performances of Diketopyrrolopyrrole Sensitizers for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Peng Gao, Thomas Wesley Holcombe, Paramaguru Ganesan

Two D-pi-A dyes, one with a strong electron withdrawing cyanoacrylic acid DPP 20 and one with a weak acceptor carboxylic acid DPP 21 have been synthesized and characterized for their application in dye-sensitized solar cells. This allows us to understand t ...

Amer Chemical Soc2015

Efficient and stable large-area perovskite solar cells with inorganic charge extraction layers

Michael Graetzel, Wei Chen, Weiwei Zhang, Jian Liu, Yinghui Wu

The recent dramatic rise in power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) has triggered intense research worldwide. However, high PCE values have often been reached with poor stability at an illuminated area of typically less than 0 ...

American Association for the Advancement of Science2015

Stable and Efficient Perovskite Solar Cells Based on Titania Nanotube Arrays

Michael Graetzel, Mohammad Khaja Nazeeruddin, Thomas Moehl, Peng Gao, Peng Qin, Mohammad Ibrahim Dar, Neha Arora

Highly ordered 1D TiO2 nanotube arrays are fabricated and applied as nanocontainers and electron transporting material in CH3NH3PbI3 perovskite solar cells. The optimized device shows a power conversion efficiency of 14.8%, and improved stability under an ...

Wiley-V C H Verlag Gmbh2015

A Methoxydiphenylamine-Substituted Carbazole Twin Derivative: An Efficient Hole-Transporting Material for Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Paul Gratia, Antonio Abate

The small-molecule-based hole-transporting material methoxydiphenylamine-substituted carbazole was synthesized and incorporated into a CH3NH3PbI3 perovskite solar cell, which displayed a power conversion efficiency of 16.91%, the second highest conversion ...

Wiley-VCH Verlag GmbH2015

Long-Range π-Conjugation in Phenothiazine-containing Donor-Acceptor Dyes for Application in Dye-Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Carole Graetzel, Thomas Moehl, Mateusz Barnaba Wielopolski, Yuxiang Yu, Jinhyun Kim

Four organic donor–π-bridge–acceptor dyes containing phenothiazine as a spacer and cyanoacrylic acid as an acceptor were synthesized and tested as sensitizers in dye-sensitized solar cells (DSCs). The influence of iodide- and cobalt-based redox electrolyte ...

Wiley-VCH Verlag Berlin2015

Enhancing the Stability of Porphyrin Dye-Sensitized Solar Cells by Manipulation of Electrolyte Additives

Michael Graetzel, Shaik Mohammed Zakeeruddin, Paul Joseph Dyson, Chenyi Yi, Hoi Nok Tsao, Pui Shan Genevieve Lau

The use of porphyrin-based photosensitizers with superior light-harvesting properties has enabled the power conversion efficiency of dye-sensitized solar cells (DSCs) to reach 13% under full sun illumination. However, a major limitation of such devices cor ...

Wiley-V C H Verlag Gmbh2015

High-Efficiency Polycrystalline Thin Film Tandem Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Antonio Abate, Fan Fu

A promising way to enhance the efficiency of CIGS solar cells is by combining them with perovskite solar cells in tandem devices. However, so far, such tandem devices had limited efficiency due to challenges in developing NIR-transparent perovskite top cel ...

Amer Chemical Soc2015

Analysing the effect of crystal size and structure in highly efficient CH3NH3PbI3 perovskite solar cells by spatially resolved photo- and electroluminescence imaging

Michael Graetzel, Jeong-Hyeok Im

CH3NH3PbI3 perovskite solar cells with a mesoporous TiO2 layer and spiro-MeOTAD as a hole transport layer (HTL) with three different CH3NH3I concentrations (0.032 M, 0.044 M and 0.063 M) were investigated. Strong variations in crystal size and morphology r ...

Royal Society of Chemistry2015

An Optically Transparent Iron Nickel Oxide Catalyst for Solar Water Splitting

Michael Graetzel, Xile Hu, Stanley David Tilley, Aswani Yella, Carlos Gilberto Morales Guio, Matthew Thomas Mayer

Sunlight-driven water splitting to produce hydrogen fuel is an attractive method for renewable energy conversion. Tandem photoelectrochemical water splitting devices utilize two photoabsorbers to harvest the sunlight and drive the water splitting reaction. ...

2015

Predicting the Open-Circuit Voltage of CH3NH3PbI3 Perovskite Solar Cells Using Electroluminescence and Photovoltaic Quantum Efficiency Spectra: the Role of Radiative and Non-Radiative Recombination

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Nevena Vaskova Marinova, Wolfgang Richard Tress

The remarkably high open-circuit voltage of methylammonium lead iodide perovskite solar cells is investigated. Both the theoretical maximum and the real open-circuit voltage are predicted from electroluminescence and photovoltaic external quantum efficienc ...

Wiley-VCH Verlag Berlin2015

Semi-transparent perovskite solar cells for tandems with silicon and CIGS

Michael Graetzel, Norman Pellet, Julian Burschka

A promising approach for upgrading the performance of an established low-bandgap solar technology without adding much cost is to deposit a high bandgap polycrystalline semiconductor on top to make a tandem solar cell. We use a transparent silver nanowire e ...

Royal Society of Chemistry2015

Light Harvesting and Charge Recombination in CH3NH3PbI3 Perovskite Solar Cells Studied by Hole Transport Layer Thickness Variation

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Robin Humphry-Baker, Mohammad Ibrahim Dar, Nevena Vaskova Marinova, Wolfgang Richard Tress

A tailored optimization of perovskite solar cells requires a detailed understanding of the processes limiting the device efficiency. Here, we study the role of the hole transport layer (HTL) spiro-MeOTAD and its thickness in a mesoscopic TiO2-based solar c ...

American Chemical Society2015

Investigation of electrodeposited cobalt sulphide counter electrodes and their application in next-generation dye sensitized solar cells featuring organic dyes and cobalt-based redox electrolytes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Thomas Moehl, Julien Edouard Frey, Simon Mathew

Cobalt sulphide (CoS) films are potentiodynamically deposited on fluorine-doped tin oxide (FTO) coated glass substrates employing one, three and five sweep cycles (CoS-I, CoS-III and CoS-V respectively). Analysis of the CoS-III film by impedance spectrosco ...

Elsevier Science Bv2015

Efficient screen printed perovskite solar cells based on mesoscopic TiO2/Al2O3/NiO/ carbon architecture

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mingkui Wang, Thomas Moehl

We present efficient perovskite solar cells using a mesoscopic TiO2/Al2O3/NiO/carbon structure as framework. The CH(3)NH(3)Pbl(3)-based device with quadruple-layer architecture achieves a power conversion efficiency of 15.03% under AM 1.5G illumination. De ...

Elsevier Science Bv2015

Mechanosynthesis of the hybrid perovskite CH3NH3PbI3: characterization and the corresponding solar cell efficiency

Michael Graetzel, Shaik Mohammed Zakeeruddin, Marius Franckevicius, Daniel Prochowicz

We present a facile mechanochemical route for the preparation of hybrid CH3NH3PbI3 (MAPbI(3)) perovskite particles with the size of several hundred nanometers for high-efficiency thin-film photovoltaic devices. Powder X-ray diffraction measurements demonst ...

Royal Society of Chemistry2015

Insight into D-A-pi-A Structured Sensitizers: A Promising Route to Highly Efficient and Stable Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yinghui Wu

The dye-sensitized solar cell (DSSC) is one of the Most promising photovoltaic technologies with potential of low cost, light weight, and good flexibility. The practical application of DSSCs requires further improvement in power conversion efficiency and l ...

Amer Chemical Soc2015

Control and Study of the Stoichiometry in Evaporated Perovskite Solar Cells

Michael Graetzel, Joël Teuscher, Nicolas Tétreault

Herein, we present the precise stoichiometric control of methlyammonium lead iodide perovskite thin-films using high vacuum dual-source vapor-phase deposition. We found that UV/Vis absorption and emission spectra were inadequate for assessing precisely the ...

Wiley-VCH Verlag Berlin2015

Low-Temperature Atomic Layer Deposition of Crystalline and Photoactive Ultrathin Hematite Films for Solar Water Splitting

Michael Graetzel, Marcel Roland Schreier, Ludmilla Steier, Matthew Thomas Mayer, Jingshan Luo

We developed a low-temperature atomic layer deposition route to deposit phase pure and crystalline hematite (alpha-Fe2O3) films at 230 degrees C without the need for postannealing. Homogenous and conformal deposition with good aspect ratio coverage was dem ...

American Chemical Society2015

Double D-pi-A Dye Linked by 2,2'-Bipyridine Dicarboxylic Acid: Influence of para- and meta-Substituted Carboxyl Anchoring Group

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aravind Kumar Chandiran, Peng Gao, Paramaguru Ganesan

Starting from 2,2-bipyridine dicarboxylic acid, two new (D--A)(2) sensitizers, including m-DA with the carboxyl anchoring group substituted meta to the donor-bridge moiety and p-DA with a para-substituted anchoring group, were synthesized in order to evalu ...

Wiley-Blackwell2015

Investigation of Interfacial Charge Separation at PbS QDs/ (001) TiO2 Nanosheets Heterojunction Solar Cell

Michael Graetzel, Jacques-Edouard Moser, Elham Ghadiri, Lioz Etgar

In the recent years, the heterojunction solar cells based on quantum dots (QDs) have attracted attention due to strong light absorbing characteristics and the size effect on the bandgap tuning. This paper reports on the kinetics of interfacial charge separ ...

Wiley-Blackwell2015

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