Ab Initio Nonadiabatic Dynamics of Semiconductor Materials via Surface Hopping Method

Photoinduced carrier dynamic processes are without doubt the main driving force responsible for the efficient performance of semiconductor nanomaterials in applications like photoconversion and photonics.Nevertheless,establishing theoretical insights into these processes is computationally challenging owing to the multiple factors involved in the processes,namely reaction rate,material surface area,material composition etc.Modelling of photoinduced carrier dynamic processes can be performed via nonadiabatic molecular dynamics(NA-MD)methods,which are methods specifically designed to solve the time-dependent Schrodinger equation with the inclusion of nonadiabatic couplings.Among NA-MD methods,surface hopping methods have been proven to be a mighty tool to mimic the competitive nonadiabatic processes in semiconductor nanomaterials,a worth noticing feature is its exceptional balance between accuracy and computational cost.Consequently,surface hopping is the method of choice for modelling ultrafast dynamics and more complex phenomena like charge separation in Janus transition metal dichalcogenides-based van der Waals heterojunction materials.Covering latest stateof-the-art numerical simulations along with experimental results in the field,this review aims to provide a basic understanding of the tight relation between semiconductor nanomaterials and the proper simulation of their properties via surface hopping methods.Special stress is put on emerging state-ot-the-art techniques.By highlighting the challenge imposed by new materials,we depict emerging creative approaches,including high-level electronic structure methods and NA-MD methods to model nonadiabatic systems with high complexity.

Preparation and Characterization of Porous Carbon from Mixed Leaves for High-Performance Supercapacitors

With the increasing demand of sustainable and eco-friendly resources,it is very attractive to use waste leaves for activated carbon(AC)preparation that can be used in supercapacitors.Considering the practically collected leaves are commonly in mixed nature,and extra efforts are needed to sort these mixtures,we here report the first preparation of AC using mixed leaves from different plants,including Platanus acerifolia(PA),Firmiana platanifolia(FP)and Pistia stratiotes(PS),and compared the results with single leaves-derived AC materials.These leave-derived AC samples were characterized with FESEM,EDS,FTIR and Raman spectroscopy,and electrochemical tests.The AC derived from mixed leaves(PA3FP1PS2AC)showed a good specific capacitance of 246 F·g−1 at 1 A·g−1 in aqueous 3 mol·L^(-1)KOH.This sample further showed the largest specific capacitance of 201 F·g−1 at 5 A·g−1,as compared with the non-mixed AC samples,and a good stability of 100.0%capacitance retention over 1000 cycles.Utilizing mixed leaves for AC preparation is not only demonstrated to be a promising approach of low cost and high-performance AC production for supercapacitor applications,but may also help environmental protection by reducing the invasive species problem.