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Search Publications by: Edwin J. Heilweil (Fed)

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Displaying 1 - 25 of 132

Studies of spatial uniformity and jitter in SiC UV SPADs

June 15, 2023
Author(s)
Joshua Bienfang, Edwin J. Heilweil, Anand Sampath, Gregory Garrett, Jonathan Shuster, Jeremy Smith, Michael Derenge, Daniel Habersat, Reza Gandhi, Sergei Dolinsky, Enrico Bellotti, michael wrabeck
Ultraviolet single-photon avalanche detectors (UV-SPAD) that are low cost, size, weight, and power as well as resilient to shock, high temperatures and stray magnetic fields have a number of applications. SiC is attractive for UV SPADs as it is inherently

Predicting solar cell performance from terahertz and microwave spectroscopy

February 26, 2022
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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