@article{wang_li_ardekani_serrano-lujan_wang_ramezani_wilmington_chauhan_epps_darabi_et al._2023, title={Sustainable materials acceleration platform reveals stable and efficient wide-bandgap metal halide perovskite alloys}, volume={6}, ISSN={["2590-2385"]}, DOI={10.1016/j.matt.2023.06.040}, abstractNote={The vast chemical space of emerging semiconductors, like metal halide perovskites, and their varied requirements for semiconductor applications have rendered trial-and-error environmentally unsustainable. In this work, we demonstrate RoboMapper, a materials acceleration platform (MAP), that achieves 10-fold research acceleration by formulating and palletizing semiconductors on a chip, thereby allowing high-throughput (HT) measurements to generate quantitative structure-property relationships (QSPRs) considerably more efficiently and sustainably. We leverage the RoboMapper to construct QSPR maps for the mixed ion FA1−yCsyPb(I1−xBrx)3 halide perovskite in terms of structure, bandgap, and photostability with respect to its composition. We identify wide-bandgap alloys suitable for perovskite-Si hybrid tandem solar cells exhibiting a pure cubic perovskite phase with favorable defect chemistry while achieving superior stability at the target bandgap of ∼1.7 eV. RoboMapper’s palletization strategy reduces environmental impacts of data generation in materials research by more than an order of magnitude, paving the way for sustainable data-driven materials research.}, number={9}, journal={MATTER}, author={Wang, Tonghui and Li, Ruipeng and Ardekani, Hossein and Serrano-Lujan, Lucia and Wang, Jiantao and Ramezani, Mahdi and Wilmington, Ryan and Chauhan, Mihirsinh and Epps, Robert W. and Darabi, Kasra and et al.}, year={2023}, month={Sep}, pages={2963–2986} }
 @article{ardekani_wilmington_vutukuru_chen_brandt_swan_gundogdu_2021, title={Broadband micro-transient absorption spectroscopy enabled by improved lock-in amplification}, volume={92}, ISSN={["1089-7623"]}, url={https://doi.org/10.1063/5.0060244}, DOI={10.1063/5.0060244}, abstractNote={Recent breakthroughs in material development have increased the demand for characterization methods capable of probing nanoscale features on ultrafast time scales. As the sample reduces to atomically thin levels, an extremely low-level signal limits the feasibility of many experiments. Here, we present an affordable and easy-to-implement solution to expand the maximum sensitivity of lock-in detection systems used in transient absorption spectroscopy by multiple orders of magnitude. By implementation of a tuned RC circuit to the output of an avalanche photodiode, electric pulse shaping allows for vastly improved lock-in detection. Furthermore, a carefully designed “peak detector” circuit provides additional pulse shaping benefits, resulting in even more lock-in detection signal enhancement. We demonstrate the improvement of lock-in detection with each of these schemes by performing benchmark measurements of a white-light continuum signal and micro-transient absorption spectroscopy on a few-layer transition metal dichalcogenide sample. Our results show the practicality of ultrafast pump–probe spectroscopy for many high-sensitivity experimental schemes.}, number={10}, journal={REVIEW OF SCIENTIFIC INSTRUMENTS}, author={Ardekani, Hossein and Wilmington, Ryan L. and Vutukuru, Mounika and Chen, Zhuofa and Brandt, Ryan and Swan, Anna K. and Gundogdu, Kenan}, year={2021}, month={Oct} }
 @article{vutukuru_ardekani_chen_wilmington_gundogdu_swan_2021, title={Enhanced Dielectric Screening and Photoluminescence from Nanopillar-Strained MoS2 Nanosheets: Implications for Strain Funneling in Optoelectronic Applications}, volume={4}, ISSN={["2574-0970"]}, url={https://doi.org/10.1021/acsanm.1c01368}, DOI={10.1021/acsanm.1c01368}, abstractNote={Nonuniform strain on multilayer transition-metal dichalcogenide (TMDC) nanosheets is an exciting path toward practical optoelectronic devices, as it combines the advantages of localized control of optical and electronic properties with ease of fabrication. However, the weaker photoluminescence (PL) due to their indirect nature poses a challenge to their application. Here, we demonstrate extraordinary enhancement of PL from multilayer MoS2 nanosheets under nonuniform strain generated by nanopillars. We observe charge and exciton funneling to the pillar strain apex. The screening from the increased exciton and charge density lowers the exciton binding energy and renormalizes the band gap. Hence, we attribute the dramatic increase in PL to dissociation of bound excitons to free electron–hole pairs, showing that nonuniform strain on TMDC nanosheets can effectively manipulate the nature of light–matter interaction in these atomically thin materials for application in novel strain-engineered optoelectronics.}, number={8}, journal={ACS APPLIED NANO MATERIALS}, publisher={American Chemical Society (ACS)}, author={Vutukuru, Mounika and Ardekani, Hossein and Chen, Zhuofa and Wilmington, Ryan L. and Gundogdu, Kenan and Swan, Anna K.}, year={2021}, month={Aug}, pages={8101–8107} }
 @article{wilmington_ardekani_rustagi_bataller_kemper_younts_gundogdu_2021, title={Fermi liquid theory sheds light on hot electron-hole liquid in 1L-MoS2}, volume={103}, ISSN={["2469-9969"]}, url={https://doi.org/10.1103/PhysRevB.103.075416}, DOI={10.1103/PhysRevB.103.075416}, abstractNote={Room-temperature electron-hole liquid has recently been experimentally identified in low-dimensional transition metal dichalcogenides. Here, the authors demonstrate that a first-principles Fermi liquid model effectively predicts the photoluminescence response of this phenomenon. Using density functional theory, in conjunction with previous Raman and photoluminescence spectroscopy results, they present a consistent quantitative picture of the electron-hole liquid phase transition in suspended, heat-strained 1$L$-MoS${}_{2}$ monolayers. They show a 23-fold increase in photoluminescence per unit of direct gap carrier density and 9:1 indirect-direct hole population ratio at high strain.}, number={7}, journal={PHYSICAL REVIEW B}, author={Wilmington, R. L. and Ardekani, H. and Rustagi, A. and Bataller, A. and Kemper, A. F. and Younts, R. A. and Gundogdu, K.}, year={2021}, month={Feb} }