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Search Publications by: Edwin J. Heilweil (Fed)

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Displaying 1 - 25 of 128

Predicting solar cell performance from terahertz and microwave spectroscopy

February 26, 2022
Hannes Hempel, Edwin J. Heilweil, Timothy Magnanelli
Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Previously reported values for lead-halide perovskites vary by orders

Unraveling the compositional heterogeneity and carrier dynamics of alkali cation doped 3D/2D perovskites with improved stability

December 11, 2020
Ming Chun Tang, Siyuan Zhang, Nhan V. Nguyen, Edwin J. Heilweil, Christina A. Hacker, Timothy J. Magnanelli, Thomas D. Anthopoulos
Preventing the degradation of hybrid perovskite by humid air remains a challenge for their future commercial utilization. 3D/2D perovskites with hierarchical architecture have attracted significant attention due to their promising power conversion

Efficient hybrid mixed-ion perovskite photovoltaics: in situ diagnostics of the roles of cesium and potassium alkali cation addition

June 19, 2020
Ming Chun Tang, Yuanyuan Fan, Dounya Barrit, Ruipeng Li, Hoang X. Dang, Siyuan Zhang, Timothy J. Magnanelli, Nhan V. Nguyen, Edwin J. Heilweil, Christina A. Hacker, Detlet-M Smilgies, Kui Zhao, Aram Amassian, Thomas D. Anthopoulos
Perovskite photovoltaics have made extraordinary progress in efficiency and stability in the past few years owing to process and formulation developments like antisolvent drip and mixed-cation mixed-halide compositions. Perovskite solar cells performance

Polarization Dependence of Charge Conduction in Conjugated Polymer Films Investigated with Time- Resolved Terahertz Spectroscopy

March 6, 2020
Timothy J. Magnanelli, Sebastian Engmann, Jared K. Wahlstrand, John C. Stephenson, Lee J. Richter, Edwin J. Heilweil
We interrogate polarization anisotropy associated with charge conduction in films of the block co polymer PCDTPT, consisting of alternating cyclopenta dithiophene (donor) and thiadiazolo pyridine (acceptor) units with respect to sample morphology. Film

Carrier mobility of silicon by sub-bandgap time-resolved terahertz spectroscopy

February 26, 2020
Timothy J. Magnanelli, Edwin J. Heilweil
Low density charge mobility from below bandgap, two-photon photoexcitation of bulk Silicon (Si) is interrogated using time-resolved terahertz spectroscopy (TRTS). Total charge mobility is measured as a function of excitation frequency and fluence (charge

Photodynamics of [FeFe]-Hydrogenase Model Compounds with Bidentate Heterocyclic Ligands

July 23, 2019
Wyatt Thornley, Sarah Wirick, Maximilian Riedel-Topper, Nathan J. DeYonker, Thomas E. Bitterwolf, Christopher J. Stromberg, Edwin J. Heilweil
Two asymmetrically structured model compounds for the hydrogen-generating [Fe-Fe]-hydrogenase active site were investigated to determine the ultrafast photodynamics, structural intermediates, and photoproducts compared to more common symmetric di-iron

Contact and Non-Contact Measurement of Electronic Transport in Individual 2D SnS Colloidal Semiconductor Nanocrystals

September 24, 2018
Adam J. Biacchi, Son T. Le, Brian G. Alberding, Joseph A. Hagmann, Sujitra J. Pookpanratana, Edwin J. Heilweil, Curt A. Richter, Angela R. Hight Walker
Colloidal-based solution syntheses offer a scalable and cost-efficient means of producing 2D nanomaterials in high yield. While much progress has been made towards the controlled and tailorable synthesis of semiconductor nanocrystals in solution, it

Femtosecond Laser Eyewear Protection: Measurements and Precautions for Amplified High Power Applications

September 24, 2018
Christopher J. Stromberg, Sarah Wirick, Maximilian Riedel-Topper, Brian Alberding, Joshua A. Hadler, Edwin J. Heilweil
Ultrafast lasers have become increasingly important as research tools in laboratories and commercial enterprises suggesting laser safety, personal protection and awareness becomes ever more important. Laser safety eyewear are typically rated by their

Optical Properties of Meloxicam in the Far-Infrared Spectral Region

August 17, 2018
Yusuf S. Aytekin, Mustafa Koturk, Adam Zaczek, Timothy M. Korter, Edwin J. Heilweil, Okan Esenturk
One of the most commonly used nonsteroidal anti-inflammatory active pharmaceutical ingredient called Meloxicam has been characterized spectroscopically both by Terahertz (THz) time domain spectroscopy (THz-TDS) and by Fourier Transform Infrared (FTIR)

Photochemical Dynamics of a Trimethyl-Phosphine Derivatized [FeFe]-Hydrogenase Model Compound

August 17, 2018
Edwin J. Heilweil, Rachel L. Meyer, Tara M. Biser, Anet D. Zhandosova, Christopher J. Stromberg
Coupling photosensitizers with [FeFe]-hydrogenase model compounds can potentially create light- driven catalysts for production of hydrogen gas from acidic protons. Though there have been many studies on the synthesis, kinetics, and reaction mechanisms of

Effectiveness of Laser Safety Eyewear under Real-World Conditions

March 18, 2018
Christopher J. Stromberg, Edwin J. Heilweil, Joshua A. Hadler
Ultrafast lasers have become increasingly important as research tools in chemistry, which means laser safety is becoming more important. Laser safety glasses represent the last line of defense to protect users from potentially life-altering eye injuries

Ultrafast Laser Eyewear Protection: Measurements and Precautions

September 25, 2017
Christopher J. Stromberg, Joshua A. Hadler, Brian Alberding, Edwin J. Heilweil
Ultrafast laser systems are becoming more widespread throughout the research and industrial communities yet eye protection for these high power, bright pulsed sources still require scrupulous characterization and testing before use. Femtosecond lasers

Elucidating the Structural and Electronic Properties of Solution-Synthesized 2D SnS Crystals

March 28, 2017
Adam J. Biacchi, Brian G. Alberding, Son T. Le, Joseph A. Hagmann, Sugata Chowdhury, Curt A. Richter, Edwin J. Heilweil, Angela R. Hight Walker
The vast majority of nanoscale 2D materials are synthesized by exfoliation or gas phase deposition techniques. Alternatively, bottom-up colloidal solution syntheses offer a scalable and cost-efficient means of producing 2D nanomaterials in high yield

Static and Time-Resolved Terahertz Measurements of Photoconductivity in Solution-Deposited Ruthenium Oxide Nanofilms

January 25, 2017
Brian Alberding, Paul A. Desario, Adam D. Dunkelberger, Debra R. Rolison, Jeffrey C. Owrutsky, Edwin J. Heilweil
Thin film Ruthenium Oxide (RuO2) is a promising alternative material as a conductive electrode in electronic applications because its rutile crystalline form is metallic and highly conductive. Herein, a previously established solution-deposition multi

Charge Carrier Dynamics and Mobility Determined by Time-Resolved Terahertz Spectroscopy on Films of Nano-to-Micrometer-Sized Colloidal Tin(II) Monosulfide

August 1, 2016
Brian Alberding, Adam Biacchi, Angela R. Hight Walker, Edwin J. Heilweil
Tin(II) monosulfide (SnS) is a semiconductor material with an intermediate band gap, high absorption coefficient is the visible range, and consists of earth abundant, non-toxic elements. For these reasons, SnS has generated much interest for incorporation