發(fā)布時(shí)間：2018-05-18 19:10

  本文選題：有機(jī)半導(dǎo)體 + 有機(jī)磁電阻�。� 參考：《山東大學(xué)》2016年博士論文

【摘要】：與無機(jī)半導(dǎo)體和全碳材料(如碳納米管、石墨烯等)相比,有機(jī)半導(dǎo)體材料有諸多不同。大部分有機(jī)半導(dǎo)體材料在形貌上高度無序,化學(xué)純度不高,元素之間通過共價(jià)鍵結(jié)合,分子之間通過范德瓦耳斯力結(jié)合。過去三十多年來,有機(jī)半導(dǎo)體作為重要的電磁光功能材料已取得長足發(fā)展。與無機(jī)器件相比,有機(jī)半導(dǎo)體器件具有價(jià)格低、易制備、柔性等優(yōu)點(diǎn),因而在應(yīng)用方面有十分廣闊的前景。有機(jī)發(fā)光二極管,有機(jī)太陽能電池,有機(jī)場效應(yīng)管,有機(jī)激光器和有機(jī)傳感器等均已研制出來。隨著以有機(jī)發(fā)光二極管為代表的有機(jī)電子學(xué)器件在實(shí)際應(yīng)用中獲得巨大成功,有機(jī)自旋電子學(xué)也已進(jìn)入到大規(guī)模研究活動(dòng)中。有機(jī)自旋電子學(xué)的研究催生了一系列對磁場敏感的概念器件的發(fā)明,如磁場傳感器、自旋閥、自旋有機(jī)發(fā)光二極管等。以器件為導(dǎo)向的研究進(jìn)展迅速,但有機(jī)自旋電子學(xué)不僅包含自旋相關(guān)的技術(shù),也包含對器件中電子自旋物理過程的理解。目前文獻(xiàn)中已經(jīng)提出大量的物理模型和假設(shè)。有機(jī)半導(dǎo)體中的載流子為極化子和雙極化子,而且輸運(yùn)多為分子間躍遷的模式,這導(dǎo)致有機(jī)半導(dǎo)體載流子遷移率很低。材料的高無序性導(dǎo)致載流子密度在同一種材料的不同樣品中也可能是不同的。有機(jī)自旋電子學(xué)不僅包含信息載流子的自旋交換,還包含對磁場敏感的載流子輸運(yùn),這些現(xiàn)象都與自旋弛豫有關(guān)。在有機(jī)自旋閥器件中,自旋極化電流從具有不同矯頑力的鐵磁電極注入到有機(jī)活性層中。由于兩電極的磁化方向可以獨(dú)立改變,該器件可以制成載流子自旋過濾器。反過來,由于器件對外磁場敏感,又可用作磁場探測器。自旋閥器件要求載流子遷移率高,自旋弛豫時(shí)間長。有機(jī)半導(dǎo)體中自旋-軌道耦合較弱,這似乎對自旋極化的保持有利。但有機(jī)半導(dǎo)體遷移率低、超精細(xì)場強(qiáng)、高無序、載流子自旋高定域性又都不利于自旋極化的保持。這些特點(diǎn)一方面會(huì)使有機(jī)自旋電子學(xué)在基本原理以及技術(shù)上顯得豐富多樣,另一方面也給自旋現(xiàn)象的實(shí)驗(yàn)研究帶來了困難。由于存在電極雜散場,傳統(tǒng)的磁光克爾效應(yīng)顯微技術(shù)不再適用。迄今為止,最有可能在微觀上追蹤自旋極化的實(shí)驗(yàn)有兩個(gè),一是μ子自旋轉(zhuǎn)動(dòng)譜法,根據(jù)實(shí)驗(yàn)測量,有機(jī)半導(dǎo)體中自旋擴(kuò)散長度只有納米量級。另一個(gè)實(shí)驗(yàn)是雙光子光電子發(fā)射譜實(shí)驗(yàn),這個(gè)實(shí)驗(yàn)給鐵磁／有機(jī)層界面自旋注入提供了令人信服的證據(jù),但卻不能探測有機(jī)半導(dǎo)體材料中的自旋極化輸運(yùn)。發(fā)現(xiàn)電荷輸運(yùn)受磁場影響的現(xiàn)象,進(jìn)一步使問題變得復(fù)雜。有機(jī)磁電阻效應(yīng)(OMAR)指的是有機(jī)發(fā)光二極管器件在弱磁場(幾十個(gè)mT)下,其電阻可以有高達(dá)1-10%的變化率。近十年來,在不同有機(jī)材料,特別是溶液和真空蒸發(fā)制備的聚合物薄膜有機(jī)發(fā)光二極管器件中,有機(jī)磁電阻效應(yīng)均有報(bào)道。磁電阻的大小、正負(fù)、偏壓依賴關(guān)系均有研究。幾個(gè)mT量級的OMAR和磁電致發(fā)光也有報(bào)道。還有研究發(fā)現(xiàn)OMAR可以在磁場變化過程中改變符號。一個(gè)有意思的觀點(diǎn)是,OMAR可能揭示了有磁場感官能力的鳥利用地磁場判斷方向的物理機(jī)制,而且有可能涉及宏觀室溫量子相干現(xiàn)象。目前關(guān)于OMAR效應(yīng),主要的理論模型包括：電子-空穴對機(jī)制(或者叫載流子對機(jī)制),雙極化子機(jī)制和激子-極化子碰撞機(jī)制。在電子-空穴對模型中,自旋弛豫過程控制了單態(tài)和三重態(tài)電子-空穴對的相互轉(zhuǎn)化,而單、三重態(tài)電子-空穴對的濃度共同決定了器件的電導(dǎo)率。外加靜磁場可以改變超精細(xì)場對自旋弛豫的影響,從而出現(xiàn)磁電阻。通常認(rèn)為,這一模型只能描述或正、或負(fù)的OMAR,但不能同時(shí)描述兩者。激子極化子碰撞模型認(rèn)為,三態(tài)激子與極化子碰會(huì)撞導(dǎo)致極化子遷移率下降,而外磁場可以改變?nèi)貞B(tài)激子的濃度,進(jìn)而改變碰撞次數(shù),產(chǎn)生磁電阻效應(yīng)。這兩個(gè)模型都需要器件中同時(shí)存在正負(fù)載流子,但OMAR還可以在單極器件中出現(xiàn)。Bobbert等人提出,通過引入雙極化子,可以很好地解釋單極器件中的OMAR。模型認(rèn)為外磁場可以調(diào)控極化子和雙極化子比率,由于極化子和雙極化子的遷移率不同,導(dǎo)致加磁場前后電導(dǎo)率不同。有實(shí)驗(yàn)在單極器件中發(fā)現(xiàn)了高達(dá)2000%的OMAR,也可以很好地用雙極化子模型來解釋。對于器件中磁相互作用的來源,有研究考慮了超精細(xì)相互作用和自旋-軌道相互作用,還有研究認(rèn)為外磁場對載流子的洛侖茲力改變了載流子在格點(diǎn)間的躍遷積分,進(jìn)而改變電流,產(chǎn)生磁電阻現(xiàn)象。目前,有機(jī)磁電阻研究最大的挑戰(zhàn)在于從實(shí)驗(yàn)上直接檢驗(yàn)這些理論的正確性。目前有實(shí)驗(yàn)組利用光譜技術(shù)開展相關(guān)的研究。OMAR效應(yīng)的發(fā)現(xiàn)促進(jìn)了人們對有機(jī)半導(dǎo)體材料中載流子自旋特性的深入思考。2010年,Tarafder等人通過第一性原理計(jì)算發(fā)現(xiàn),Alq3分子中注入電子會(huì)出現(xiàn)凈磁矩。計(jì)算發(fā)現(xiàn),Alq3分子在電子注入前后,三個(gè)A1-N鍵和三個(gè)A1-O鍵會(huì)發(fā)生變化,同時(shí)費(fèi)米面附近會(huì)發(fā)生自旋劈裂。他們研究了諸如電荷量從0到1.5 e時(shí)分子自旋極化的情況,發(fā)現(xiàn)分子的自旋極化隨注入電荷量成正比。因?yàn)锳lq3分子中包含金屬元素,其中的物理過程更為復(fù)雜。Hou等人計(jì)算了純有機(jī)聚噻吩分子中電荷注入引起的自發(fā)自旋極化情況。根據(jù)他們的計(jì)算,注入電荷量少的時(shí)候,系統(tǒng)不會(huì)出現(xiàn)自旋極化,只有注入電荷量的達(dá)到一定值后,系統(tǒng)才會(huì)出現(xiàn)自旋極化。另外分子的聚合度也會(huì)對自旋極化的大小有影響。有機(jī)半導(dǎo)體中注入載流子的自發(fā)自旋極化以及載流子遷移率受磁場調(diào)控等現(xiàn)象的發(fā)現(xiàn),都預(yù)示著有機(jī)半導(dǎo)體中載流子有豐富的電荷和自旋特性。而室溫有機(jī)多鐵現(xiàn)象的發(fā)現(xiàn)更加豐富了人們對于有機(jī)半導(dǎo)體材料的認(rèn)識(shí)。多鐵材料指的是能同時(shí)顯示出兩個(gè)及以上鐵性序參量的材料,如鐵電性、鐵磁性和鐵彈性。近十年來,多鐵材料以其豐富的物理性質(zhì),以及在自旋電子學(xué)、光電、熱電和傳感器等領(lǐng)域的潛在應(yīng)用,迅速成為科學(xué)研究的熱點(diǎn)。而室溫有機(jī)多鐵現(xiàn)象的發(fā)現(xiàn)和研究,為低成本、大面積地制備和開發(fā)實(shí)用型器件提供了新的思路。2009年,Giovannetti等人采用第一性原理計(jì)算結(jié)合模型方法,首次預(yù)言了在TTF-CA電荷轉(zhuǎn)移鹽材料中會(huì)出現(xiàn)多鐵現(xiàn)象。在這之后,幾種具有磁電耦合性質(zhì)的復(fù)合物器件在實(shí)驗(yàn)上被制備出來。2012年,Ren等人報(bào)道了在nw-P3HT/C60復(fù)合物中觀測到光激發(fā)鐵磁性現(xiàn)象。他們發(fā)現(xiàn),在P3HT納米線單晶中摻入C60后,光照會(huì)使器件呈現(xiàn)明顯的鐵磁性。實(shí)驗(yàn)進(jìn)一步發(fā)現(xiàn),外電場、應(yīng)力等外界刺激也會(huì)對材料磁化強(qiáng)度有影響。通常在無機(jī)多鐵材料中,磁電序出現(xiàn)的居里溫度較低。但激發(fā)鐵磁性不受這一限制,從而為室溫多鐵開辟了新的領(lǐng)域。綜上所述,有機(jī)半導(dǎo)體材料中的載流子有豐富的自旋特性,實(shí)驗(yàn)上也發(fā)現(xiàn)了很多新現(xiàn)象,但很多具體問題背后的物理機(jī)制還需要仔細(xì)研究,以便更好地理解有機(jī)半導(dǎo)體中載流子的自旋特性。本論文從機(jī)半導(dǎo)體中載流子的自旋特性入手,采用經(jīng)典的躍遷理論和一維Su-Schrieffer-Heeger (SSH)模型,分別研究了有機(jī)磁電阻現(xiàn)象,有機(jī)半導(dǎo)體中電荷注入引起的自發(fā)自旋極化和有機(jī)電荷轉(zhuǎn)移復(fù)合物器件中的光激發(fā)鐵磁性現(xiàn)象。以下是具體的研究內(nèi)容和基本結(jié)論。1.OLED器件中的磁電阻效應(yīng)。關(guān)于實(shí)驗(yàn)上發(fā)現(xiàn)的有機(jī)磁場效應(yīng),目前人們已經(jīng)提出幾個(gè)理論。我們這里采用經(jīng)典的Marcus躍遷模型,提出磁場引起載流子能級的賽曼劈裂,并改變電子在分子間躍遷率的模型,給出有機(jī)磁電阻效應(yīng)的一個(gè)經(jīng)典的解釋。此外我們還考慮了超精細(xì)相互作用,考慮了外磁場對載流子的洛倫茲力,計(jì)算發(fā)現(xiàn),在低溫下,賽曼劈裂引起的載流子躍遷率的改變可能是有機(jī)磁電阻效應(yīng)的一個(gè)來源。但是在高溫下,有機(jī)非磁性器件中外磁場引起電流的變化,更多是磁場對載流子的洛侖茲力引起的。2.有機(jī)半導(dǎo)體中電荷注入引起的自發(fā)自旋極化。我們在Hou等人研究基礎(chǔ)上,采用擴(kuò)展的一維SSH模型,考慮電子-電子相互作用,自旋反轉(zhuǎn)相互作用以及自旋-軌道耦合,理論研究了聚噻吩中電荷注入引起的自發(fā)自旋極化現(xiàn)象。模型方法的優(yōu)勢在于可以方便地計(jì)算更長的分子鏈,更多的電荷注入和更方便的參數(shù)分析。計(jì)算發(fā)現(xiàn),隨著電-聲耦合常數(shù)的增大,系統(tǒng)電子態(tài)會(huì)出現(xiàn)從擴(kuò)展到局域的突變,伴隨著電子態(tài)局域的出現(xiàn),自旋極化隨之產(chǎn)生,因此有機(jī)材料強(qiáng)的電-聲相互作用是出現(xiàn)自發(fā)自旋極化的前提。相同電荷注入量下,不同聚合度的聚噻吩,其自旋磁矩也會(huì)有所不同,我們認(rèn)為這都與電荷在分子中的局域度有關(guān)。對于小分子,分子尺寸很小,注入到分子中的電荷很容易形成局域態(tài),因此即使注入很少電子,系統(tǒng)仍然可以出現(xiàn)自旋極化。而在高分子中,注入電荷量很少時(shí),注入的電荷先是形成擴(kuò)展態(tài),注入電荷量增加到一定程度時(shí)局域態(tài)才會(huì)出現(xiàn),并與之相伴產(chǎn)生自旋極化。對于自旋-軌道耦合,因?yàn)橛袡C(jī)材料中自旋-軌道耦合強(qiáng)度很小,計(jì)算發(fā)現(xiàn)自旋-軌道耦合對自旋極化幾乎沒有影響。3.有機(jī)電荷轉(zhuǎn)移復(fù)合物中的激發(fā)鐵磁性。圍繞Ren等人在電荷轉(zhuǎn)移復(fù)合物中發(fā)現(xiàn)的光激發(fā)鐵磁性,我們采用擴(kuò)展的一維緊束縛模型,計(jì)算了有機(jī)電荷轉(zhuǎn)移復(fù)合物中,激子和電荷轉(zhuǎn)移態(tài)的自旋極化情況和變化規(guī)律。一般認(rèn)為,帶間光激發(fā)產(chǎn)物是單態(tài)激子,三態(tài)激子因?yàn)檐S遷禁阻,其數(shù)目可以忽略。而考慮自旋相關(guān)的相互作用之后,自旋不再是好的量子數(shù),所有的激子都會(huì)變成單態(tài)和三態(tài)激子的疊加態(tài)。計(jì)算發(fā)現(xiàn),對于電荷轉(zhuǎn)移態(tài),電子給體和受體上的自旋極化是不一樣的,因此,不論如何激發(fā),電荷轉(zhuǎn)移態(tài)總會(huì)對外顯示凈磁矩。關(guān)于電荷轉(zhuǎn)移態(tài)之間的耦合,我們在計(jì)算中考慮了不同的耦合方式,計(jì)算發(fā)現(xiàn),對于不同的自旋排列,系統(tǒng)的能量有高低,但是總能對外顯示凈磁矩。
[Abstract]:Compared with inorganic semiconductors and all carbon materials (such as carbon nanotubes, graphene, etc.), there are many different organic semiconductors. Most organic semiconductors are highly disordered and with low chemical purity. The elements are combined by covalent bonds between the elements and the molecules are combined by Fan De Valis. Over the past thirty years, organic semiconductors have been made. Compared with inorganic devices, organic semiconductor devices have many advantages, such as low price, easy preparation and flexibility. Therefore, organic light-emitting diodes, organic solar cells, organic field effective tubes, organic lasers and organic sensors have been developed. As organic electronic devices represented by organic light emitting diodes have gained great success in practical applications, organic spintronics have also entered into large-scale research activities. The study of organic spintronics has led to a series of concept devices sensitive to magnetic fields, such as magnetic field sensors, spin valves, spin organics. Light emitting diodes and so on. The progress of device oriented research is rapid, but organic spintronics includes not only spin related technology, but also the understanding of the physical process of electron spin in the device. A large number of physical models and hypotheses have been proposed in the current literature. The mode of intermolecular transition, which leads to the low mobility of the organic semiconductor carrier, may lead to the carrier density in different samples of the same material. Organic spintronics includes not only the spin exchange of the information carrier, but also the carrier transport of the magnetic field, which are sensitive to the magnetic field. In organic spin valve devices, the spin polarization current is injected into the organic active layer from the ferromagnetic electrodes with different coercivity. Because the magnetization direction of the two electrode can be changed independently, the device can be made into a carrier spin filter. In turn, it is sensitive to the external magnetic field and can be used as a magnetic field probe. The spin valve device requires high carrier mobility and long spin relaxation time. The spin orbit coupling in organic semiconductors is weak, which seems to be beneficial to spin polarization. However, the mobility of organic semiconductors is low, hyperfine field strength, high disorder, and high domain of carrier spin is not conducive to the maintenance of spin polarization. It will make organic spintronics rich in basic principles and techniques. On the other hand, the experimental study of spin phenomena is difficult. Due to the existence of the heterostray field, the traditional magneto-optical Kerr effect microscopy is no longer applicable. So far, there are two experiments that are most likely to trace spin polarization on microviews, one is mu. According to the experimental measurements, the spin diffusion length of the organic semiconductor is only nanometers. The other experiment is a two-photon photoelectron emission spectrum experiment. This experiment provides convincing evidence for the spin injection of the ferromagnetic / organic layer interface, but it can not detect the spin polarization transport in the organic semiconductors. The phenomenon that the current charge transport is affected by the magnetic field further complicates the problem. The organic magnetoresistance effect (OMAR) refers to the resistance of organic light-emitting diodes in the weak magnetic field (dozens of mT) to a change rate of up to 1-10%. In the last ten years, the polymer films prepared in different organic materials, especially in solution and vacuum evaporation, have been prepared. The effects of organic magnetoresistance are reported in the light emitting diode (LED) devices. The size of magnetic resistance, positive and negative, and bias dependence have been studied. Several mT orders of OMAR and magnetoelectric luminescence are also reported. And the study found that OMAR can change symbols in the process of magnetic field change. A deliberate view that OMAR may reveal the sense of the magnetic field The capable birds use the geomagnetic field to determine the physical mechanism of the direction, and may involve the quantum coherence phenomena at the macroscopic room temperature. At present, the main theoretical models of the OMAR effect include: the electron hole pair mechanism (or the carrier pair mechanism), the dipole mechanism and the exciton dipole collision mechanism. In the electron hole pair model, the spin is spins. The relaxation process controls the mutual conversion of the single state and the three state electron hole pair, while the concentration of the single and three heavy electron hole pairs determines the electrical conductivity of the device together. The external magnetostatic magnetic field can change the effect of the hyperfine field on the spin relaxation, thus producing the magnetoresistance. The shock model of exciton polaron shows that the collision between the three state exciton and the polaron leads to the decrease of the mobility of the polaron, and the external magnetic field can change the concentration of the three heavy exciton, and then change the number of collisions and produce the magnetoresistance effect. The two models all need both positive and negative carriers in the device, but OMAR can also be in the monopole. In the device,.Bobbert et al. Put forward that by introducing the dipole, the OMAR. model in the unipolar device can be well explained that the external magnetic field can regulate the ratio of the polaron and the dipolaron. Due to the different mobility of the polaron and the dipole, the conductivity is different before and after the addition of the magnetic field. The experiment is found to be up to 20 in the monopole device. The OMAR of 00% can also be well explained by the dipolaron model. For the source of magnetic interaction in the device, the study considers the hyperfine interaction and spin orbit interaction, and the study considers that the Lorentz force of the external magnetic field changes the transition integral between the carriers at the lattice, and then changes the current and produces the magnetoelectricity. At present, the greatest challenge for the research of the organic magnetoresistance is to test the correctness of these theories directly. At present, the experimental group is using the spectral technology to carry out the related research on the.OMAR effect and promote the people to think deeply about the spin characteristics of the carrier in organic semiconductors for.2010 years. Tarafder et al. The calculation of the principle of sexual principle shows that the net magnetic moment of the injection of electrons in the Alq3 molecule is found. It is found that the three A1-N and three A1-O keys will change before and after the electron injection, and the spin splitting will occur near the surface of the Fermi surface. They have studied the spin polarization such as the charge amount from 0 to 1.5 e, and found the spin polarization of the molecule. As the injection charge is proportional to the amount of charge, because the Alq3 molecule contains metal elements, the physical process is more complicated by.Hou et al. The spontaneous spin polarization caused by charge injection in the pure organic polythiophene is calculated. According to their calculations, the system will not have spin polarization when the charge amount is less, only the amount of injection charge is reached. After a certain value, the spin polarization will occur in the system. The degree of polymerization of the molecules also affects the spin polarization. The discovery of the spontaneous spin polarization of the carriers in the organic semiconductors and the discovery of the carrier mobility by the magnetic field all indicate the rich charge and spin properties of the carriers in the organic semiconductors. The discovery of the phenomenon of organic iron at room temperature has enriched the understanding of organic semiconductors. Multi iron materials refer to materials that can show two and more iron order parameters at the same time, such as ferroelectricity, ferromagnetism and ferroelasticity. In the last ten years, the material has its rich physical properties, as well as spintronics, photoelectric, thermoelectric, and thermoelectric properties. The potential applications of sensors and other fields have rapidly become the focus of scientific research. The discovery and study of the phenomenon of organic iron at room temperature provides a new way of thinking for the low cost, large area preparation and development of practical devices. Giovannetti et al. Used the first principle calculation method to predict the charge transfer in TTF-CA for the first time. After this, several composite devices with magnetic and electrical coupling properties have been prepared for.2012 years after this. Ren et al. Reported the observation of the ferromagnetism in the nw-P3HT/C60 complex. They found that after the incorporation of C60 in the P3HT nanowire single crystal, the light illuminated the device with an obvious ferromagnetic field. The experiment further found that external electric field, stress and other external stimuli also affect the magnetization of the material. Generally, in the inorganic multi iron material, the Curie temperature in the magnetoelectric order is lower. However, the excitation of ferromagnetism is not limited, which opens up a new field for the room temperature multi iron. The carrier of organic semiconductors is abundant. Many new phenomena have been found in the spin properties of the rich, but the physical mechanisms behind many specific problems need to be carefully studied in order to better understand the spin characteristics of the carriers in the organic semiconductors. This paper starts with the spin properties of the carrier in the machine semiconductor, and uses the classical transition theory and the one-dimensional Su-Schrieffer-Heeger. (SSH) model, the phenomenon of organic magnetoresistance, the spontaneous spin polarization induced by charge injection in organic semiconductors and the light excitation ferromagnetism in the organic charge transfer complex devices are studied. The following is the specific research content and the basic conclusion of the magnetoresistance effect in the.1.OLED device. Several theories have been put forward by the former people. Here we use the classical Marcus transition model to suggest that the magnetic field causes the Zeeman splitting of the carrier energy level, and changes the model of the electron transition rate between the molecules and gives a classic explanation of the effect of the organic magnetoresistance. In addition, we consider the hyperfine interaction and consider the external magnetic field to load. It is found that the change of the carrier transition rate caused by Zeeman splitting at low temperature may be a source of the organic magnetoresistance effect at low temperature. But at high temperature, the magnetic field caused by the magnetic field in the organic nonmagnetic device causes the change of the current, and more is the charge of the.2. organic semiconductor caused by the magnetic field to the Lorentz force of the carrier. On the basis of Hou et al. Based on the extended one-dimensional SSH model, we consider the electron electron interaction, spin reversal interaction and spin orbit coupling, and study the spontaneous spin polarization phenomena caused by the charge injection in polythiophene. The advantage of the model method is that it can be easily calculated. The longer molecular chain, more charge injection and more convenient parameter analysis. It is found that with the increase of the electrical acoustic coupling constant, the electronic state will appear from the expansion to the local, with the appearance of the electronic state, the spin polarization is produced, so the spontaneous spin polarization of the organic material is strong. Under the same charge injection amount of polythiophene with different degree of polymerization, the spin magnetic moment of the polythiophene will vary. We think that this is all related to the local degree of the charge in the molecule. For small molecules, the size of the molecule is very small, the charge into the molecule is very easy to form a local state, so the system can still appear even if there is little electron injection. When the injection charge is very small, the injected charge is first formed, and the local state will appear when the charge amount is increased to a certain extent, and the spin polarization is associated with it. For spin orbit coupling, the spin orbit coupling is found to be found in the organic material. The spin polarization has little effect on the magnetization of the excited ferromagnetism in the.3. organic charge transfer complex. We have calculated the spin polarization and the variation of the exciton and charge transfer states in the organic charge transfer complex by using the extended one-dimensional tight binding model around the light excited ferromagnetism found in the charge transfer complex of Ren et al. It is generally believed that the interband light excitation product is a single state exciton, and the number of the three state excitons can be ignored because of the transition. Considering the spin dependent interaction, the spin is no longer a good quantum number, and all the excitons will become the superposition state of the single state and the three state exciton. The calculation is found that the charge transfer state, the electron donor and the receptor are found. The spin polarization is different. Therefore, no matter how excited, the charge transfer state always shows the net magnetic moment.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：O469

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