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Aswani Yella

Cette personne a quitté l’EPFL

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Publications associées (36)

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Advanced High-Throughput Rational Design of Porphyrin-Sensitized Solar Cells Using Interpretable Machine Learning

Michael Graetzel, Shaik Mohammed Zakeeruddin, Aswani Yella

Accurately predicting the power conversion efficiency (PCE) in dye-sensitized solar cells (DSSCs) represents a crucial challenge, one that is pivotal for the high throughput rational design and screening of promising dye sensitizers. This study presents pr ...

2024

Molecular Engineering of a Fluorene Donor for Dye-Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Joël Teuscher, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Negar Ashari Astani, Aswani Yella, Julien Edouard Frey, Simon Mathew, Lauren Elizabeth Polander

To improve their efficiency beyond the state-of-the-art, D-pi-A dyes must display increased spectral breadth and account for the physical limitations observed in the dye. sensitized solar cells. In particular, they should be designed to control the electro ...

Amer Chemical Soc2013

Molecular Engineering of Push-Pull Porphyrin Dyes for Highly Efficient Dye-Sensitized Solar Cells: The Role of Benzene Spacers

Michael Graetzel, Shaik Mohammed Zakeeruddin, Aswani Yella

Porphyrins have drawn much attention as sensitizers owing to the large absorption coefficients of their Soret and Q bands in the visible region. In a donor and acceptor zinc porphyrin we applied a new strategy of introducing 2,1,3-benzothiadiazole (BTD) as ...

Wiley-Blackwell2014

Unraveling the Dual Character of Sulfur Atoms on Sensitizers in Dye-Sensitized Solar Cells

Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Joël Teuscher, Thomas Moehl, Aswani Yella, Peng Gao, Peng Gao, Sadig Aghazada

Cyclometalated ruthenium sensitizers have been synthesized that differ with number of thiophene units on the auxiliary ligands. Sensitizers possessing four (SA25, SA246, and SA285) or none (SA282) sulfur atoms in their structures, were tested in solar cell ...

Amer Chemical Soc2016

Organic Dyes Containing Coplanar Dihexyl-Substituted Dithienosilole Groups for Efficient Dye-Sensitised Solar Cells

Michael Graetzel, Ravindranathan Thampi, Aswani Yella

A chromophore containing a coplanar dihexyl-substituted dithienosilole (CL1) synthesised for use in dye-sensitised solar cells displayed an energy conversion efficiency of 6.90% under AM 1.5 sunlight irradiation. The new sensitiser showed a similar fill fa ...

Hindawi Publishing Corporation2017

Nanocrystalline Rutile Electron Extraction Layer Enables Low-Temperature Solution Processed Perovskite Photovoltaics with 13.7% Efficiency

Michael Graetzel, Mohammad Khaja Nazeeruddin, Leo-Philipp Heiniger, Aswani Yella, Peng Gao, Peng Gao

We demonstrate low-temperature (70 degrees C) solution processing of TiO2/CH3NH3PbI3 based solar cells, resulting in impressive power conversion efficiency (PCE) of 13.7%. Along with the high efficiency, a strikingly high open circuit potential (V-OC) of 1 ...

American Chemical Society2014

Thiocyanate-Free Ru(II) Sensitizers with a 4,4-Dicarboxyvinyl-2,2-bipyridine Anchor for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

A new class of thiocyanate-free Ru(II) sensitizers with 4,4-dicarboxyvinyl-2,2-bipyridine anchor and two trans-oriented pyrid-2-yl pyrazolate (or triazolate) functional chromophores is synthesized, characterized, and evaluated in dye-sensitized solar cells ...

Wiley-Blackwell2013

Thiocyanate-Free Ruthenium(II) Sensitizers for Dye-Sensitized Solar Cells Based on the Cobalt Redox Couple

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

Two thiocyanate-free ruthenium(II) sensitizers, TFRS-41 and TFRS-42, with distinctive dialkoxyphenyl thienyl substituents were successfully prepared and tested for potential applications in making dye-sensitized solar cells (DSCs). Subsequent device fabric ...

Wiley-VCH Verlag Berlin2014

Porphyrin-Sensitized Solar Cells with Cobalt (II/III)-Based Redox Electrolyte Exceed 12 Percent Efficiency

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Aravind Kumar Chandiran, Aswani Yella, Chenyi Yi, Hoi Nok Tsao

The iodide/triiodide redox shuttle has limited the efficiencies accessible in dye-sensitized solar cells. Here, we report mesoscopic solar cells that incorporate a Co((II/III))tris(bipyridyl)-based redox electrolyte in conjunction with a custom synthesized ...

American Association for the Advancement of Science2011

Molecular Design Principles for Near-Infrared Absorbing and Emitting Indolizine Dyes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Aron Joel Huckaba

Desirable components for dye-sensitzed solar cell ( DSC) sensitizers and fluorescent imaging dyes include strong donating building blocks coupled with well-balanced acceptor functionalities for absorption beyond the visible range. We have evaluated the eff ...

Wiley-Blackwell2016

Perovskite solar cells employing organic charge-transport layers

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Yonghui Lee

Thin-film photovoltaics play an important role in the quest for clean renewable energy. Recently, methylammonium lead halide perovskites were identified as promising absorbers for solar cells(1). In the three years since, the performance of perovskite-base ...

Nature Publishing Group2014

Sterically demanded unsymmetrical zinc phthalocyanines for dye-sensitized solar cells

Mohammad Khaja Nazeeruddin, Aswani Yella, Peng Gao, Peng Gao

Three new sterically demanding unsymmetrical zinc phthalocyanines have been designed and synthesized as sensitizers for dye-sensitized solar cells. All three unsymmetrical phthalocyanines have been completely characterized by elemental analyses, mass spect ...

Elsevier2013

Acetylene-bridged dyes with high open circuit potential for dye-sensitized solar cells

Pascal Comte, Michael Graetzel, Shaik Mohammed Zakeeruddin, Thomas Moehl, Aswani Yella, Fabrizio Giordano

A series of simple metal-free organic dyes MS1-MS3 have been designed and synthesized, and their optical, electrochemical, and photovoltaic properties were investigated. The molecular structures are based on a push-pull framework with a triphenylamine, nap ...

RSC Publishing2014

Low temperature crystalline titanium dioxide by atomic layer deposition for dye-sensitized solar cells

Pascal Comte, Michael Graetzel, Mohammad Khaja Nazeeruddin, Aravind Kumar Chandiran, Leo-Philipp Heiniger, Aswani Yella, Morgan Mertens Stefik

Low temperature processing of dye-sensitized solar cells (DSC) is crucial to enable commercialization with low-cost, plastic substrates. Prior studies have focused on mechanical compression of premade particles on plastic or glass substrates, however, this ...

Amer Chemical Soc2013

Peripherally and Axially Carboxylic Acid Substituted Subphthalocyanines for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Aswani Yella

A series of subphthalocyanines (SubPcs) bearing a carboxylic acid group either at the peripheral or axial position have been designed and synthesized to investigate the influence of the COOH group positions on the dye-sensitized solar cell (DSSC) performan ...

Wiley-Blackwell2014

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, Peng Gao, Thomas Wesley Holcombe

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

Sub-Nanometer Conformal TiO2 Blocking Layer for High Efficiency Solid-State Perovskite Absorber Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aravind Kumar Chandiran, Aswani Yella, Peng Gao, Peng Gao, Matthew Thomas Mayer

A mere 2 nm conformal titanium dioxide overlayer coated by atomic layer deposition is shown to act as a blocking layer for high-efficiency solid-state perovskite (CH3NH3PbI3) absorber-based solar cells. Surpassing the existing multilayer passivation, this ...

Wiley-Blackwell2014

Electron Kinetics in Dye Sensitized Solar Cells Employing Anatase with (101) and (001) Facets

Pascal Comte, Michael Graetzel, Mohammad Khaja Nazeeruddin, Ladislav Kavan, Thomas Moehl, Aswani Yella

Two phase-pure nanocrystalline anatase materials differing in the exposed crystal facets (001) or (101) are studied by electrochemical impedance spectroscopy and by transient photovoltage and photocurrent decay in dye sensitized solar cells. A larger chemi ...

Elsevier2015

Modulating dye E(S+/S*) with efficient heterocyclic nitrogen containing acceptors for DSCs

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

Acceptor motifs based on nitrogen containing heterocycles have been synthesized for use in dye-sensitized solar cells (DSCs). Through the selective addition of nitrogen atoms and increased conjugation of the nitrogen containing heterocycles the excited-sta ...

Royal Society of Chemistry2012

Dye-sensitized solar cells using cobalt electrolytes: the influence of porosity and pore size to achieve high-efficiency

Pascal Comte, Mohammad Khaja Nazeeruddin, Aswani Yella, Simon Mathew, Sadig Aghazada

Diffusion impediments in redox shuttles are a major limitation to realizing high power conversion efficiencies (PCEs) in dye sensitized solar cells (DSCs) using cobalt complexes. Mass transport limitations are strongly dependent on the pore size and the po ...

Royal Society of Chemistry2017