硒化物半导体材料制备及其光电与热电性能研究

发布时间：2018-03-10 09:49

本文选题：太阳能　切入点：硒化物半导体　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：随着全球工业化进程的加快,能源短缺和环境污染已经成为世界范围内不容忽视的两大问题,严重制约着社会长期稳定发展。研究和开发新能源已经成为全球能源发展的趋势。其中太阳能以其取之不尽用之不竭的广泛性及无噪音无污染的清洁性获得了巨大关注,并成为最为理想的绿色能源；然而太阳辐射还具有分散性与间歇性等特点,通常无法直接利用,而是需要被有效转化与存储方可加以利用。本文总结和概括了太阳能的主要转化方式,对太阳能光热转换、光化学转换、光电转换以及热电转换进行了详细的原理介绍与现状分析。在此基础上,分别采用熔融-冷却(Melt-quenching)方法和热注入(Hot injection)方法制备了金属硒化物陶瓷和纳米颗粒,研究了组成与制备工艺等对硒化物陶瓷物相组成、微观结构及光电性能,以及反应物组成、反应温度、反应时间等对硒化物纳米颗粒微观结构及性能的影响规律。论文主要研究结果如下：1、以多晶锗、锑、硒及铜等为原料,采用melt-quenching方法,制备了Cu2GeSe3-Sb2Se3体系陶瓷。研究了组成及制备工艺对陶瓷物相组成、微观结构及光电性能的影响。研究发现,原料配比并不影响陶瓷材料晶体类型,陶瓷体系中只存在Cu2GeSe3与Sb2Se3晶体,但对陶瓷中两种晶体比例及微观结构有显著影响,随着原料中Cu(Ge)/Sb配比增加,陶瓷材料中Cu2GeSe3/Sb2Se3比例随之上升,微观结构中Sb2Se3棒状结构逐渐淹没于致密的Cu2GeSe3晶体当中。Cu2GeSe3与Sb2Se3晶体比例的不同对于材料光电性能没有显著影响,该体系陶瓷都具有类似的电导率、电流-电压(I-V)曲线变化规律,且仅显示出P型半导体光电流增强现象。在光密度400 W·m-2条件下,-0.6 V偏压下的最高光电流密度达到了50 μA·cm-2。研究了CuI取代Cu对陶瓷材料结构与性能的影响,由于I元素的引入,陶瓷中产生了新的SbSeI晶相,而且新相的产生打断了原本贯通的Cu2GeSe3导电通道,不仅使材料孔隙增多,更使得陶瓷材料同时具有了P型与N型半导体光电效应。初步分析了这类陶瓷材料可能的导电机制,为进一步将该体系新材料用于太阳能电池器件奠定了基础。2、以锑、硒、铜及CuI等为原料,采用melt-quenching方法,制备了不含稀有元素锗(Ge)的Cu3SbSe4-Sb2Se3体系陶瓷。研究了组成及制备工艺对陶瓷物相组成、微观结构及光电性能的影响。研究发现,原料配比并不影响陶瓷材料晶体类型,陶瓷体系中只存在Cu3SbSe4与Sb2Se3晶体,但对陶瓷中两种晶体比例及微观结构有显著影响,随着原料中Cu含量的增加,陶瓷材料中Cu3SbSe4/Sb2Se3比例随之上升,微观结构中Sb2Se3棒状结构逐渐淹没于致密的Cu3SbSe4晶体当中。Cu3SbSe4与Sb2Se3晶体比例的不同对于材料光电性能没有显著影响,该体系陶瓷都具有类似的电导率、Ⅰ-Ⅴ曲线变化规律,并同时显示P型半导体与N型半导体光电流增强现象,在光密度400 W·m-2条件下,-0.6 V偏压下最高光电流密度也达到了50 μA·cm-2。利用Cu3SbSe4取代Cu2GeSe3与Sb2Se3构建微观PN异质结共同组成了Cu3SbSe4-Sb2Se3体系陶瓷,在成功取代了稀有元素Ge的同时,保留了陶瓷优异的光电性能。研究了Ⅰ元素掺杂对Sb2Se3电阻率的影响,在不引起杂质晶相的情况下,少量Ⅰ元素掺杂即可将Sb2Se3电阻率降低105倍,这对于改善具有优异的光吸收和热电性能却一直被其高电阻限制的Sb2Se3具有重大意义。Ⅰ元素掺杂对于Cu3SbSe4-Sb2Se3体系陶瓷性能的影响与对Cu2GeSe3-Sb2Se3体系陶瓷的影响类似,Ⅰ掺杂Sb2Se3也打断了原本贯通的Cu3SbSe4导电通道,但由于Ⅰ掺杂显著提高了Sb2Se3导电性,光生载流子不仅通过Cu3SbSe4也可通过Sb2Se3晶体,从而同时显示出P型与N型半导体光电效应。3、采用热注入法,将室温硒源前驱物Se-ODE注射到热的阳离子溶液中,通过控制反应温度和时间,成功制备了CuSe纳米颗粒和高质量单晶二维六方晶纳米片,该合成过程避免了使用有毒的不稳定的烷基膦类化合物作为有机溶液,具有绿色环保,产率高等优点。研究了反应温度、反应时间及添加A13+对于CuSe晶体物相、形貌尺寸及禁带宽度的影响。研究发现,随反应时间延长,初始纳米颗粒逐渐增大最终形成二维纳米片。用定向附着理论解释了二维纳米片的生长过程,硒化铜纳米片通过纳米晶粒之间晶面匹配、定向聚集生长而成。反应过程中,A13+离子可以通过吸附硒离子延缓纳米片的生长速率,无A13+离子参与条件下硒化铜纳米颗粒在180℃反应温度下仅需10分钟即可生长为二维纳米片。通过控制反应时间可以制备近红外光学吸收可调的硒化铜纳米材料,可以根据目标应用对半导体禁带宽度的要求进行合成制备,极大地拓宽了硒化铜在近红外光谱范围的应用。4、采用热注入法制备了Cu3SbSe4纳米颗粒。研究发现,纳米颗粒具有单晶并呈现单分散的类球型结构。通过控制反应温度和时间,纳米颗粒平均尺寸可以在15 nm(0分钟)到110 nm(60分钟)之间调节。将Cu3SbSe4纳米颗粒作原料用于制备块体热电材料,与常规固相反应制备的Cu3SbSe热电材料相比,用Cu3SbSe4纳米颗粒制备的热电材料可有效减少晶粒尺寸,增加晶界散射,从而有效降低材料热导率。研究了Sn元素掺杂对Cu3SbSe4热电材料性能的影响,掺杂Sn元素可显著提高材料电导率,结合纳米颗粒制备的Cu3SbSe4热电材料较低的热导率,两者共同提高了材料的功率因子,以Cu3Sb0.98Sn0.02Se4纳米颗粒为原料,采用热压烧结制备的块体热电材料,在575 K时的热电优值达到了0.50。
[Abstract]:With the rapid development of industrialization, energy shortage and environmental pollution have become the two major issues in the world can not be ignored, seriously restricting the long-term stable development of the society. The research and development of new energy has become a global trend of development. The solar energy to clean its inexhaustible inexhaustible wide and no noise and no pollution the obtained great attention, and become the most ideal green energy; however, solar radiation has dispersion and intermittent characteristics, usually cannot be used directly, but to be effective conversion and storage can be used. This paper summarizes the main mode of transformation of solar energy, solar thermal, photochemical conversion, photoelectric conversion and thermoelectric conversion are introduced and analyzed in detail. The principle and status quo on the basis of this, using melt cooling method (Melt-quenching) Injection (Hot injection) and hot metal selenide ceramic nano particles and the preparation method, the composition and preparation process on the phase composition of selenide ceramic material, and photoelectric properties of microstructure, composition, and reaction temperature, influence of reaction time on the microstructure of selenide nanoparticles and performance. The main results are as follows: 1, in polycrystalline germanium, antimony, selenium and copper as raw materials, using the method of melt-quenching, Cu2GeSe3-Sb2Se3 ceramics were prepared. The composition and preparation process on the phase composition of ceramic material, influence of microstructure and photoelectric properties. The study found that does not affect the ratio of raw materials of ceramic materials Cu2GeSe3 and Sb2Se3 crystal type, crystal ceramic exists only in the system, but has significant influence on the microstructure of two kinds of ceramics and crystals in proportion with the raw material of Cu (Ge) /Sb ratio increased, Cu2GeSe3/Sb2Se ceramic material The proportion of 3 rise, Cu2GeSe3 crystal rod like structure of Sb2Se3 microstructure gradually submerged in the dense.Cu2GeSe3 and Sb2Se3 crystals with different proportion for photoelectric properties of materials had no significant effect on the ceramic has similar electrical conductivity, current voltage (I-V) variation curve, and only shows the P type semiconductor photocurrent enhancement the phenomenon. In the optical density of 400 W under the condition of m-2, the highest photoelectric -0.6 V bias current density reached 50 A - cm-2. of CuI to replace the effect of Cu on the structure and properties of ceramic materials, due to the introduction of the I element, ceramic produced a new SbSeI crystal phase, and the new phase generated interrupt the original Cu2GeSe3 conductive channel through, not only makes the material porosity increase, the ceramic material has the photoelectric effect of P type and N type semiconductor. Preliminary analysis of the conduction mechanism of the ceramic material, into a This step will be new material system for solar cell devices has laid the foundation to.2, antimony, selenium, copper and CuI as raw materials, using the method of melt-quenching, the preparation does not contain rare elements germanium (Ge) Cu3SbSe4-Sb2Se3 ceramics was studied. The composition and preparation process on the phase composition of ceramic material, and photoelectric properties the microstructure. It is found that does not affect the ratio of raw materials of ceramic materials Cu3SbSe4 and Sb2Se3 crystal type, crystal ceramic exists only in the system, but has significant influence on the microstructure of two kinds of ceramics and crystals in proportion, with the increase of Cu content in raw material, ceramic material in the proportion of Cu3SbSe4/Sb2Se3 increased, Cu3SbSe4 crystal microstructure of Sb2Se3 rod structure gradually submerged in the dense.Cu3SbSe4 and Sb2Se3 crystals with different proportion for photoelectric properties of materials had no significant effect on the ceramic has similar conductivity, I-V The change curve, and at the same time that the P type semiconductor and N type semiconductor photocurrent enhancement, optical density at 400 W under the condition of m-2, -0.6 V under the high light bias current density reached 50 A - cm-2. by Cu3SbSe4 to replace Cu2GeSe3 and Sb2Se3 to build micro PN heterojunction composed of Cu3SbSe4-Sb2Se3 ceramics. In successfully replaced the rare element Ge and retains the excellent optical and electrical properties of ceramic was studied. Effect of element doping on the resistivity of Sb2Se3, in which the impurity crystal phase under the condition of a small amount of 1 element doped Sb2Se3 can be 105 times lower resistivity, it has to improve the light absorption and excellent thermoelectric properties are has been of great significance to its high resistance limit. I Sb2Se3 doping affects the performance of Cu3SbSe4-Sb2Se3 system for ceramics and influence on ceramic Cu2GeSe3-Sb2Se3 system similar to that of doped Sb2Se3 Cu3SbSe4 originally interrupted conducting channel through, but because of doping enhances the conductivity of Sb2Se3, the photogenerated carriers not only through Cu3SbSe4 can also pass through the Sb2Se3 crystal, which also shows the photoelectric effect of P type and N type semiconductor.3 by hot injection method, the temperature of selenium source precursor Se-ODE injected into cationic hot solution, by controlling the reaction temperature and time, high quality single crystal CuSe nanoparticles and six dimensional nano films were prepared successfully, the synthesis process avoids the use of toxic volatile alkyl phosphonic compounds as organic solution, green environmental protection, high yield. The effects of reaction temperature, reaction time and addition of A13+ for the CuSe crystal phase, morphology and size effect of the band gap. The study found that with the prolonging of reaction time, initial nanoparticles increased gradually formed nanosheets with oriented attachment theory. The theory explains the growth process of two-dimensional nanosheets, copper selenide nanoplates through nano grain crystal surface matching, and directional aggregation. In the reaction process, the growth rate of A13+ ions by adsorption of selenium ion delay nanosheets, A13+ ion in the condition of copper selenide nano particles in the reaction temperature 180 DEG C only needs 10 minutes for the growth of nanosheets. Through the preparation of near infrared optical absorption adjustable copper selenide nano materials can control the reaction time can be prepared according to the target application of semiconductor band gap, greatly expanded the application of.4 copper selenide in the near infrared spectral range, using Cu3SbSe4 nanoparticles were prepared into nano particles. The study found that having a single crystal and presents a spherical structure of monodisperse. By controlling the reaction temperature and time, the average size of nano particles in the 15 nm (0 Minutes) to 110 nm (60 minutes). The adjustment between Cu3SbSe4 nanoparticles as raw materials for the preparation of bulk thermoelectric materials, compared with conventional Cu3SbSe thermoelectric materials prepared by solid state reaction, thermoelectric materials with Cu3SbSe4 nano particle preparation can effectively reduce the increase of grain size, grain boundary scattering, thus effectively reducing the thermal conductivity. Study on the effect of Sn doping on properties of Cu3SbSe4 thermoelectric materials, Sn doping can significantly improve the electrical conductivity, thermal conductivity of Cu3SbSe4 thermoelectric materials with nano particles were prepared by a low rate, both increase the power factor, using Cu3Sb0.98Sn0.02Se4 nano particles as raw material, prepared by hot pressing sintering bulk thermoelectric materials in 575 K, ZT value reached 0.50.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN304

【相似文献】