Publications by Aswani Yella | EPFL Graph Search

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

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

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

Thieno[3,4-b]pyrazine as an Electron Deficient pi-Bridge in D-A-pi-A DSCs

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

Thieno[3,4-b]pyrazine (TPz) is examined as an electron deficient pi-bridge enabling near-infrared (NIR) spectral access in dye sensitized solar cells (DSCs). Seven dissymmetric dyes for DSCs were synthesized (NL2-NL8) with TPz as the pi-bridge utilizing pa ...

Amer Chemical Soc2016

Solar cell and process for producing the same

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

The present invention relates to photoanodes, solar cells and methods and processes for producing the same. In some embodiments, the solar cells of the invention can do without a sintered nanoporous scaffold layer, making it possible to produce the solar c ...

2016

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, 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

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

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

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

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

Redox couple for electrochemical and optoelectronic devices

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Jun Ho Yum, Aswani Yella, Hoi Nok Tsao

The present invention provides an improved redox couple for electrochemical and optoelectronic devices. The redox couple is based on a complex of a first row transition metal, said complex containing at least one mono-, bi-, or tridentate ligand comprising ...

2014

Near-IR Photoresponse of Ruthenium Dipyrrinate Terpyridine Sensitizers in the Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella

Coordination of bidentate 5-pentafluorophenyldipyrrinate (pfpdp) or 5-(2-thienyl)dipyrrinate (2-tdp) to a Ru-II center bearing 2,2':6',2 ''-terpyridine-4,4',4 ''-tricarboxylate (tctpy) and a NCS- ligand results in strongly light-absorbing complexes [Ru(tct ...

American Chemical Society2014

Subphthalocyanines: Active molecules for molecular photovoltaics

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

Amer Chemical Soc2014

Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers

Michael Graetzel, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Negar Ashari Astani, Aswani Yella, Peng Gao, Simon Mathew

Dye-sensitized solar cells have gained widespread attention in recent years because of their low production costs, ease of fabrication and tunable optical properties, such as colour and transparency. Here, we report a molecularly engineered porphyrin dye, ...

2014

Quantum-Confined ZnO Nanoshell Photoanodes for Mesoscopic Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aravind Kumar Chandiran, Aswani Yella, Chenyi Yi, Mojtaba Abdi Jalebi, Mohammad Ibrahim Dar

We present a photoanode for dye-sensitized solar cell (DSC) based on ZnO nanoshell deposited by atomic layer deposition at 150°C, on a mesoporous insulating template. An ultrathin layer of ZnO between 3 and 6 nm, which exhibits quantum confinement effect, ...

American Chemical Society2014

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

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Kuan-Lin Wu, Filippo de Angelis, Shilong Wang

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

High-Surface-Area Porous Platinum Electrodes for Enhanced Charge Transfer

Michael Graetzel, Marcel Roland Schreier, Francesco Stellacci, Aswani Yella, Yelin Hu, Morgan Mertens Stefik, Stefan Guldin

Cobalt-based electrolytes are highly tunable and have pushed the limits of dye-sensitized solar cells, enabling higher open-circuit voltages and new record efficiencies. However, the performance of these electrolytes and a range of other electrolytes suffe ...

Wiley-V C H Verlag Gmbh2014

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, 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

A durable SWCNT/PET polymer foil based metal free counter electrode for flexible dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Thomas Moehl, Syed Ghufran Hashmi, Aswani Yella, Fabrizio Giordano

An ITO free, highly conductive PET foil is fabricated by depositing aqueous single-walled carbon nanotube (SWCNT) ink that exhibits remarkable durability when exposed to severe mechanical stability tests. Excellent adhesion of the SWCNT film on PET was obt ...

Royal Society of Chemistry2014

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