A short presentation of chemical engineering evolution,as guided by its paradigms,is exposed.The first paradigm–unit operations–has emerged as a necessity of systematization due to the explosion of chemical industri...A short presentation of chemical engineering evolution,as guided by its paradigms,is exposed.The first paradigm–unit operations–has emerged as a necessity of systematization due to the explosion of chemical industrial applications at the end of 19th century.The birth in the late 1950s of the second paradigm–transport phenomena–was the consequence of the need for a deep,scienti fic knowledge of the phenomena that explain what happens inside of unit operations.In the second part of 20th century,the importance of chemical product properties and qualities has become essentially in the market fights.Accordingly,it was required with additional and even new fundamental approaches,and product engineering was recognized as the third paradigm.Nowadays chemical industry,as a huge materials and energy consumer,and with a strong ecological impact,couldn't remain outside of sustainability requirements.The basics of the fourth paradigm–sustainable chemical engineering–are now formulated.展开更多
Iridium complexes with dicyanovinyl-grafted phenylpyridine/l-phenylisoquinoline as ligands are synthesized and their photo- physical, electrochemical, and sensitization properties in DSSCs are investigated. The iridiu...Iridium complexes with dicyanovinyl-grafted phenylpyridine/l-phenylisoquinoline as ligands are synthesized and their photo- physical, electrochemical, and sensitization properties in DSSCs are investigated. The iridium complexes present significantly enhanced absorption from 400 to 525 nm. The 1-phenylisoquinoline-based iridium complex show bathochromic-shift emission in DMSO solution compared with their phenylpyridine-based counterpart, while their absorption response and photoluminescence peak in solid show little difference despite extension of the conjugated system. Using DSSCs, the conversion efficiency of 0.62% and open-circuit current of 1.4 mA/cm2 is achieved. The poor performance is attributed to the excited-state properties of iridium complexes according to the TD-DFT calculation.展开更多
Two-dimensional(2D) ternary materials have sprung up in a broad variety of optoelectronic applications due to their robust degree of freedom to design the physical properties of the materials through adjusting the sto...Two-dimensional(2D) ternary materials have sprung up in a broad variety of optoelectronic applications due to their robust degree of freedom to design the physical properties of the materials through adjusting the stoichiometric ratio. However, the controlled growth of high-quality 2D ternary materials with good chemical stoichiometry remains challenging, which severely impedes their further development and future device applications. Herein, we synthesize ternary Bi_(2)Te_(2)Se(BTS) flakes with a thickness down to 4 nm and a lateral dimension about 60 μm by an atmospheric-pressure solid source thermal evaporation method on a mica substrate. The phonon vibration and electrical transportation of 2D BTS are respectively investigated by temperature-dependent Raman spectrum and conductivity measurements. Furthermore, the photodetector based on 2D BTS exhibits excellent performance with a high light on/off ratio of 1300(365 nm), a wide spectral response range from 365 to 980 nm, and an ultra-fast response speed up to 2 μs. In addition, its electrical and photoelectric properties can be modulated by the gate voltage, offering an improved infrared responsivity to 2.74 A W^(-1) and an on/off ratio of 2266 under 980 nm. This work introduces an effective approach to obtain 2D BTS flakes and demonstrates their excellent prospects in optoelectronics.展开更多
文摘A short presentation of chemical engineering evolution,as guided by its paradigms,is exposed.The first paradigm–unit operations–has emerged as a necessity of systematization due to the explosion of chemical industrial applications at the end of 19th century.The birth in the late 1950s of the second paradigm–transport phenomena–was the consequence of the need for a deep,scienti fic knowledge of the phenomena that explain what happens inside of unit operations.In the second part of 20th century,the importance of chemical product properties and qualities has become essentially in the market fights.Accordingly,it was required with additional and even new fundamental approaches,and product engineering was recognized as the third paradigm.Nowadays chemical industry,as a huge materials and energy consumer,and with a strong ecological impact,couldn't remain outside of sustainability requirements.The basics of the fourth paradigm–sustainable chemical engineering–are now formulated.
基金supported by the Fundamental Research Funds for the Central Universities(08143034)the National Basic Research Program of China(2013CB328705,2013CB328706)the National Natural Science Foundation of China(61275034,61106123)
文摘Iridium complexes with dicyanovinyl-grafted phenylpyridine/l-phenylisoquinoline as ligands are synthesized and their photo- physical, electrochemical, and sensitization properties in DSSCs are investigated. The iridium complexes present significantly enhanced absorption from 400 to 525 nm. The 1-phenylisoquinoline-based iridium complex show bathochromic-shift emission in DMSO solution compared with their phenylpyridine-based counterpart, while their absorption response and photoluminescence peak in solid show little difference despite extension of the conjugated system. Using DSSCs, the conversion efficiency of 0.62% and open-circuit current of 1.4 mA/cm2 is achieved. The poor performance is attributed to the excited-state properties of iridium complexes according to the TD-DFT calculation.
基金supported by the National Natural Science Foundation of China (21825103)Hubei Provincial Natural Science Foundation of China (2019CFA002)the Fundamental Research Funds for the Central Universities (2019kfy XMBZ018)。
文摘Two-dimensional(2D) ternary materials have sprung up in a broad variety of optoelectronic applications due to their robust degree of freedom to design the physical properties of the materials through adjusting the stoichiometric ratio. However, the controlled growth of high-quality 2D ternary materials with good chemical stoichiometry remains challenging, which severely impedes their further development and future device applications. Herein, we synthesize ternary Bi_(2)Te_(2)Se(BTS) flakes with a thickness down to 4 nm and a lateral dimension about 60 μm by an atmospheric-pressure solid source thermal evaporation method on a mica substrate. The phonon vibration and electrical transportation of 2D BTS are respectively investigated by temperature-dependent Raman spectrum and conductivity measurements. Furthermore, the photodetector based on 2D BTS exhibits excellent performance with a high light on/off ratio of 1300(365 nm), a wide spectral response range from 365 to 980 nm, and an ultra-fast response speed up to 2 μs. In addition, its electrical and photoelectric properties can be modulated by the gate voltage, offering an improved infrared responsivity to 2.74 A W^(-1) and an on/off ratio of 2266 under 980 nm. This work introduces an effective approach to obtain 2D BTS flakes and demonstrates their excellent prospects in optoelectronics.
