We investigate the application of the density-matrix renormalization group （DMRG） algorithm to a one-dimensional harmonic oscillator chain and compare the results with exact solutions, aiming at improving the algori...We investigate the application of the density-matrix renormalization group （DMRG） algorithm to a one-dimensional harmonic oscillator chain and compare the results with exact solutions, aiming at improving the algorithm＇s ef- ficiency. It is demonstrated that the algorithm can show quite accurate results if the procedure is properly organized; for example, by using the optimized bases. The errors of calculated ground state energy and the energy gap between the ground state and the first excited state are analyzed, and they are found to be critically dependent upon the size of the system or the energy level structure of the studied system and the number of states targeted during the DMRG procedure.展开更多
An efficient descriptor model for fast screening of potential materials for solar cell applications is presented.It works for both excitonic and non-excitonic solar cells materials,and in addition to the energy gap it...An efficient descriptor model for fast screening of potential materials for solar cell applications is presented.It works for both excitonic and non-excitonic solar cells materials,and in addition to the energy gap it includes the absorption spectrum(α(E))of the material.The charge transport properties of the explored materials are modelled using the characteristic diffusion length(Ld)determined for the respective family of compounds.The presented model surpasses the widely used Scharber model developed for bulk heterojunction solar cells.Using published experimental data,we show that the presented model is more accurate in predicting the achievable efficiencies.To model both excitonic and non-excitonic systems,two different sets of parameters are used to account for the different modes of operation.The analysis of the presented descriptor model clearly shows the benefit of includingα(E)and Ld in view of improved screening results.展开更多
The field of hybrid inorganic–organic framework materials is one of the fastest growing fields in materials science because their enormous structural and chemical diversity presents great opportunities for creating m...The field of hybrid inorganic–organic framework materials is one of the fastest growing fields in materials science because their enormous structural and chemical diversity presents great opportunities for creating many technologically relevant properties.One of the most important issues is controlling and tuning the structural,optical,thermal,mechanical and electronic properties of these complex materials by varying their chemistry,fabrication techniques and preparation conditions.Here we demonstrate that significant progress in this area may be achieved by introducing structural elements that form hydrogen bonds with the environment.Considering hybrid framework materials with different structural ordering containing protonated sulfonium cation H3S+and electronegative halogen anions(I^(−),Br^(−),Cl^(−)and F^(−)),we found that hydrogen bonding increases the structural stability of the material and may be used for tuning electronic states near the bandgap.We suggest that such a behaviour has a universal character and should be observed in hybrid inorganic–organic framework materials containing protonated cations.This effect may serve as a viable route for optoelectronic and photovoltaic applications.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274117 and 11134003, and the Shanghai Excellent Academic Leaders Program of China under Grant No 12XD1402400.
文摘We investigate the application of the density-matrix renormalization group （DMRG） algorithm to a one-dimensional harmonic oscillator chain and compare the results with exact solutions, aiming at improving the algorithm＇s ef- ficiency. It is demonstrated that the algorithm can show quite accurate results if the procedure is properly organized; for example, by using the optimized bases. The errors of calculated ground state energy and the energy gap between the ground state and the first excited state are analyzed, and they are found to be critically dependent upon the size of the system or the energy level structure of the studied system and the number of states targeted during the DMRG procedure.
文摘An efficient descriptor model for fast screening of potential materials for solar cell applications is presented.It works for both excitonic and non-excitonic solar cells materials,and in addition to the energy gap it includes the absorption spectrum(α(E))of the material.The charge transport properties of the explored materials are modelled using the characteristic diffusion length(Ld)determined for the respective family of compounds.The presented model surpasses the widely used Scharber model developed for bulk heterojunction solar cells.Using published experimental data,we show that the presented model is more accurate in predicting the achievable efficiencies.To model both excitonic and non-excitonic systems,two different sets of parameters are used to account for the different modes of operation.The analysis of the presented descriptor model clearly shows the benefit of includingα(E)and Ld in view of improved screening results.
文摘The field of hybrid inorganic–organic framework materials is one of the fastest growing fields in materials science because their enormous structural and chemical diversity presents great opportunities for creating many technologically relevant properties.One of the most important issues is controlling and tuning the structural,optical,thermal,mechanical and electronic properties of these complex materials by varying their chemistry,fabrication techniques and preparation conditions.Here we demonstrate that significant progress in this area may be achieved by introducing structural elements that form hydrogen bonds with the environment.Considering hybrid framework materials with different structural ordering containing protonated sulfonium cation H3S+and electronegative halogen anions(I^(−),Br^(−),Cl^(−)and F^(−)),we found that hydrogen bonding increases the structural stability of the material and may be used for tuning electronic states near the bandgap.We suggest that such a behaviour has a universal character and should be observed in hybrid inorganic–organic framework materials containing protonated cations.This effect may serve as a viable route for optoelectronic and photovoltaic applications.
