نتایج جستجو برای: low band-gap

تعداد نتایج: 1423945  

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم پایه 1390

در این تحقیق اتصال پپتیدی نانولوله به صفحات گرافن مورد بررسی قرار گرفته است. از میان جنبه های مختلف قابل بررسی برای این ساختارها، مطالعات ساختاری، مطالعات مربوط به انرژی تشکیل پیوند، مطالعاتnmr) )neuclear magnetic resonance و nuclear quadrupole resonance (nqr)و molecular electrostatic potential (mep)، مطالعات مربوط به شکاف انرژی (band gap)هریک از این هیبریدهای نانولوله - گرافن و همچنین بررسی ان...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1387

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم انسانی 1390

this study investigated the effects of manipulating the cognitive complexity of tasks along +/- few elements and the time limits on l2 learners writing performance. to conduct the study, 60 iranian efl learners with two levels of proficiency, low and high intermediate, were selected and assigned to three groups based on the time devoted to task completion. the participants performed both a simp...

Journal: :journal of optoelectronical nano structures 0
khojasteh zarei 1department of electronic engineering, sepidan branch,islamic azad university, sepidan, iran. ghahraman solookinejad department of physics, marvdashtbranch,islamic azad university, marvdasht, iran. masoud jabbari department of electrical engineering, marvdasht branch, islamic azad university, marvdasht, iran.

in this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for te/tm modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. after that, effects of parameters like...

Journal: :physical chemistry research 2014
mohammed bouachrine najat belghiti mohammed nassiri bennani simohamed bouzzine mohamed hamidi

the research in the short-chain organic -conjugated molecules has become one of the most interesting topics in the fields of chemistry. these compounds have become the most promising materials for the optoelectronic device technology. the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. the control of the band gap of th...

Journal: :Advanced materials and technologies 2021

Important parameters of an organic semiconductor material are the electronic band gap (Eg) and position highest occupied lowest unoccupied bands versus vacuum. These called valence conduction for inorganic semiconductors. For semiconductors defining often molecular orbital (HOMO) (LUMO). One advantage semiconducting polymers is ability to tune HOMO LUMO levels by chemical design. The photovolta...

Journal: :Solar Energy Materials and Solar Cells 2007

Journal: :physical chemistry research 2014
mohammed bouachrine fatima agda mostapha taleb tayeb abram

the research in new organic π-conjugated molecules with specific properties has become one of the most interesting topics in fields of materials chemistry. these materials are promising for optoelectronic device technology such as solar cells. on the other hand, the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. the co...

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