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Theoretical and Experimental Features of Nano-Crystals Rochelle Salt: Piezoelectric Resonance and Phase Transition
摘要： A new methodology based on Three-Electrode System (TES) technique was used to measure both, elastic (C44) and piezoelectric (d14) constants of Rochelle salt (RS) crystal. This technique was also used to observe the phase transitions at ?18 °C and 24 °C, manifested as an increase of the output signal at these temperatures. Mechanical wave attenuation coefficient (α) into the crystal was found. Also, first principle methodology in the framework of the density functional theory was utilized to confirm the electronic structure of Rochelle Salt. The results present high accuracy theoretical/experimental as well as a complete agreement with those known in the literature done by different methodologies.
关键词： Phase Transitions,Rochelle Salt Crystal,Piezoelectric Device,Ab Initio Simulation
更新于2025-09-23 15:22:29
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Metaheuristic <i>Ab Initio</i> Optimum Search for Doping Effects in Nanocarbons
摘要： We have developed a combined approach of metaheuristic optimization algorithms (MOA), such as the genetic algorithm, with an ab-initio materials simulation engine. Concurrent run of the ab-initio calculations with each different parameter set selected by the MOA searches the optimum condition within a given input-parameter space. Using this methodology, the optimum dopant and its position/structure at a graphene edge are found to be a multiple N-atoms doping at graphitic sites, which predicts to lead to better charging/discharging performance when it is used as an anode material of Li-ion battery.
关键词： genetic algorithm,lithium-ion battery,nano-carbon,ab-initio simulation,doping effect
更新于2025-09-23 15:22:29
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Dopants Control of Electron-Hole Recombination in Cesium-Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Co-Doping Supersedes Mono-Doping
摘要： Using nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory, we simulate electron-hole recombination in pristine and doped inorganic Pb-free double perovskite Cs2TiBr6. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite they do not change the fundamental bandgap of Cs2TiBr6, they decrease the NA electron-phonon coupling and accelerate decoherence, arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants respectively, suppressing electron-hole recombination. More importantly, co-doping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by co-doping in design of high performance all-inorganic Pb-free perovskite solar cells.
关键词： Co-doping,Electron-Hole Recombination,Mono-doping,Energy Conversion and Storage,Cesium-Titanium Halide Double Perovskite,Plasmonics and Optoelectronics,Time Domain Ab Initio Simulation,Dopants Control
更新于2025-09-10 09:29:36