By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon ...By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon monocrystal under dry oxygen atmosphere at 1100℃.Compared with their oxidation kinetic curves consisted of three stages,we suggested a mechanism on forming silicon oxide film.According to electron and X-ray diffraction analyses the silicon oxide films consisted of silica with different crystal structure.We also have discussed a stacking fault and a dislocation formed in the Si-Sio_2 interface region simulaneously forming silicon oxide film.展开更多
Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on ...Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on PbI2 morphology and the performances of resulting perovskite solar cells. The PbI2 morphologies and coverage rates under different formation conditions such as solvent effect, slow crystallization at room temperature and substrate-preheating, are found to be of crucial importance for preparing high-quality perovskite. The generation of loosely packed disk-like PbI2 film with interpenetrating nanopores promotes the penetration of methyl ammonium iodide （MAI）, leading to a better crystallinity of the perovskite film, and a best repeatable power conversion efficiency of 11.59% is achieved when methyl ammonium lead triiodide （CH3NH3PbI3, MAPbI3） is employed. In addition, an excellent device is also obtained with an efficiency of more than 93% to remain after working for 43 days.展开更多
Electrocatalytic CO_(2) conversion has been considered as a promising way to recycle CO_(2) and produce sustainable fuels and chemicals.However,the efficient and highly selective electrochemical reduction of CO_(2) di...Electrocatalytic CO_(2) conversion has been considered as a promising way to recycle CO_(2) and produce sustainable fuels and chemicals.However,the efficient and highly selective electrochemical reduction of CO_(2) directly into multi‐carbon(C_(2+))products remains a great challenge.Herein,we synthesized three type catalysts with different morphologies based on Cu_(2)O nanowires,and studied their morphology and crystal facet reconstruction during the pre‐reduction process.Benefiting from abundant exposure of Cu(100)crystal facet,the nanosheet structure derived Cu catalyst showed a high faradaic efficiency(FE)of 67.5%for C_(2+)products.Additionally,electrocatalytic CO_(2) reduction studies were carried out on Cu(100),Cu(110),and Cu(111)single crystal electrodes,which verified that Cu(100)crystal facets are favorable for the C_(2+)products in electrocatalytic CO_(2) reduction.Our work showed that catalysts would reconstruct during the CO_(2) reduction process and the importance in morphology and crystal facet control to obtain desired products.展开更多
文摘By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon monocrystal under dry oxygen atmosphere at 1100℃.Compared with their oxidation kinetic curves consisted of three stages,we suggested a mechanism on forming silicon oxide film.According to electron and X-ray diffraction analyses the silicon oxide films consisted of silica with different crystal structure.We also have discussed a stacking fault and a dislocation formed in the Si-Sio_2 interface region simulaneously forming silicon oxide film.
基金Project supported by the National Natural Science Foundation of China(Grant No.61404007)the Beijing Talents Fund,China(Grant No.2015000021223ZK38)
文摘Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on PbI2 morphology and the performances of resulting perovskite solar cells. The PbI2 morphologies and coverage rates under different formation conditions such as solvent effect, slow crystallization at room temperature and substrate-preheating, are found to be of crucial importance for preparing high-quality perovskite. The generation of loosely packed disk-like PbI2 film with interpenetrating nanopores promotes the penetration of methyl ammonium iodide （MAI）, leading to a better crystallinity of the perovskite film, and a best repeatable power conversion efficiency of 11.59% is achieved when methyl ammonium lead triiodide （CH3NH3PbI3, MAPbI3） is employed. In addition, an excellent device is also obtained with an efficiency of more than 93% to remain after working for 43 days.
文摘Electrocatalytic CO_(2) conversion has been considered as a promising way to recycle CO_(2) and produce sustainable fuels and chemicals.However,the efficient and highly selective electrochemical reduction of CO_(2) directly into multi‐carbon(C_(2+))products remains a great challenge.Herein,we synthesized three type catalysts with different morphologies based on Cu_(2)O nanowires,and studied their morphology and crystal facet reconstruction during the pre‐reduction process.Benefiting from abundant exposure of Cu(100)crystal facet,the nanosheet structure derived Cu catalyst showed a high faradaic efficiency(FE)of 67.5%for C_(2+)products.Additionally,electrocatalytic CO_(2) reduction studies were carried out on Cu(100),Cu(110),and Cu(111)single crystal electrodes,which verified that Cu(100)crystal facets are favorable for the C_(2+)products in electrocatalytic CO_(2) reduction.Our work showed that catalysts would reconstruct during the CO_(2) reduction process and the importance in morphology and crystal facet control to obtain desired products.
