Thin cuprous oxide films have been prepared by chemical vapor deposition(pulsed spray evaporation-chemical vapor deposition)method without post-treatment.The synthesis of cuprous oxide was produced by applying a water...Thin cuprous oxide films have been prepared by chemical vapor deposition(pulsed spray evaporation-chemical vapor deposition)method without post-treatment.The synthesis of cuprous oxide was produced by applying a water strategy effect.Then,the effect of water on the morphology,topology,structure,optical properties and surface composition of the obtained films has been comprehensively investigated.The results reveal that a pure phase of Cu2O was obtained.The introduction of a small quantity of water in the liquid feedstock lowers the band gap energy from 2.16 eV to 2.04 eV.This finding was mainly related to the decrease of crystallite size due to the effect of water.The topology analyses,by using atomic force microscope,also revealed that surface roughness decreases with water addition,namely more uniform covered surface.Moreover,theoretical calculations based on density functional theory method were performed to understand the adsorption and reaction behaviors of water and ethanol on the Cu2O thin film surface.Formation mechanism of the Cu2O thin film was also suggested and discussed.展开更多
[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric ph...[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric phosphate,[C(NH_(2))3]3PO_(4)·2H_(2)O,was successfully designed and synthesized by a solution evaporation method.[C(NH_(2))3]3PO_(4)·2H_(2)O without metal ions is composed of planar conjugated guanidine cations and PO_(4)tetrahedrons,which are connected by hydrogen bonds,forming a three-dimensional network.Physical property measurements indicate that the title compound displays an SHG response of 1.5×KH_(2)PO_(4)(KDP) and a larger birefringence (0.055@546.1 nm)compared with most reported ultraviolet nonlinear optical phosphates.Furthermore,first-principles calculations reveal that theπ-conjugated planar[C(NH_(2))3]+cations and[PO_(4)]3-groups are responsible for its excellent linear and NLOproperties.展开更多
The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the intera...The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the interaction between two perpendicular π-systems of various oligothiophene substituted spirofluorenes is conducted. The results demonstrate that the interaction be- tween two perpendicular branches is reduced by oligothiophene substitutions. Photoexcitation induced relaxation is mainly located on one of the equivalent branches or the branch with longer conjugation length. In addition to these benefits brought by 9,9-spirobifluorene center, the specific oligothiophene moieties linked to the spirt center also have properties of significant merit, such as the ability to tune energy levels and emission colors by controlling the conjugation length.展开更多
基金supported by the Ministry of Science and Technology of China(No.2017YFA0402800)the National Natural Science and Technology of China(No.91541102 and No.51476168)+2 种基金the support by Chinese Academy of Sciences for Senior International Scientists within President’s International Fellowship Initiative(PIFI)programthe financial support during his Ph.D.research stay at Bielefeld UniversityThe Moroccan institute of IRESEN is acknowledged for the financial support(Innowind13 Nanolubricant)
文摘Thin cuprous oxide films have been prepared by chemical vapor deposition(pulsed spray evaporation-chemical vapor deposition)method without post-treatment.The synthesis of cuprous oxide was produced by applying a water strategy effect.Then,the effect of water on the morphology,topology,structure,optical properties and surface composition of the obtained films has been comprehensively investigated.The results reveal that a pure phase of Cu2O was obtained.The introduction of a small quantity of water in the liquid feedstock lowers the band gap energy from 2.16 eV to 2.04 eV.This finding was mainly related to the decrease of crystallite size due to the effect of water.The topology analyses,by using atomic force microscope,also revealed that surface roughness decreases with water addition,namely more uniform covered surface.Moreover,theoretical calculations based on density functional theory method were performed to understand the adsorption and reaction behaviors of water and ethanol on the Cu2O thin film surface.Formation mechanism of the Cu2O thin film was also suggested and discussed.
基金supported by the National Natural Science Foundation of China (21975255,51890862,21921001 and U1605245)the National Key Research and Development Plan of Ministry of Science and Technology (2016YFB0402104)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB20000000)the Natural Science Foundation of Fujian Province (2019J01020758)Youth Innovation Promotion Association CAS (2019303)。
文摘[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric phosphate,[C(NH_(2))3]3PO_(4)·2H_(2)O,was successfully designed and synthesized by a solution evaporation method.[C(NH_(2))3]3PO_(4)·2H_(2)O without metal ions is composed of planar conjugated guanidine cations and PO_(4)tetrahedrons,which are connected by hydrogen bonds,forming a three-dimensional network.Physical property measurements indicate that the title compound displays an SHG response of 1.5×KH_(2)PO_(4)(KDP) and a larger birefringence (0.055@546.1 nm)compared with most reported ultraviolet nonlinear optical phosphates.Furthermore,first-principles calculations reveal that theπ-conjugated planar[C(NH_(2))3]+cations and[PO_(4)]3-groups are responsible for its excellent linear and NLOproperties.
基金financially supported by the National Basic Research Program of China (Grant No. 2009CB930601)the National Natural Science Foundation of China (Grant Nos. 20804020, 60976019, 50903028 and 20974046)+2 种基金the Program for New Century Excellent Talents in University (Grant No. NCET-07-0446)the Scientific and Technological Innovation Teams of Colleges and Universities in Jiangsu Province (Grant No. TJ207035)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications (Grant No. NY210017)
文摘The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the interaction between two perpendicular π-systems of various oligothiophene substituted spirofluorenes is conducted. The results demonstrate that the interaction be- tween two perpendicular branches is reduced by oligothiophene substitutions. Photoexcitation induced relaxation is mainly located on one of the equivalent branches or the branch with longer conjugation length. In addition to these benefits brought by 9,9-spirobifluorene center, the specific oligothiophene moieties linked to the spirt center also have properties of significant merit, such as the ability to tune energy levels and emission colors by controlling the conjugation length.
