本文選題：PbI_2 + 表面光電壓��； 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：隨著社會(huì)經(jīng)濟(jì)的發(fā)展,一系列的環(huán)境問(wèn)題接踵而來(lái),如何充分地利用能源而又有效地降解污染已經(jīng)成為解決問(wèn)題的重點(diǎn),而具有光伏效應(yīng)和光催化能力的半導(dǎo)體材料就成為解決問(wèn)題的突破點(diǎn)。半導(dǎo)體材料產(chǎn)生光伏響應(yīng)并參與光催化過(guò)程主要依靠于光生電荷分離、遷移及復(fù)合過(guò)程。以上光生電荷的行為一般發(fā)生在半導(dǎo)體的表面,研究半導(dǎo)體表面光電性質(zhì)可以引導(dǎo)光伏響應(yīng)和光催化效率的提高。PbI_2為p型半導(dǎo)體材料,禁帶寬度較大,約為2.4 eV。具有較高的原子系數(shù)、較大的禁帶寬度、電阻率高和載流子遷移率壽命極大等諸多優(yōu)點(diǎn),能有效的利用太陽(yáng)能,具有在光伏、檢測(cè)器、傳感器和光催化中的應(yīng)用的潛力。由于其光生電荷的產(chǎn)生、傳輸和復(fù)合機(jī)理研究甚少,嚴(yán)重限制了 PbI_2的應(yīng)用。基于以上原因,本文針對(duì)退火前后的PbI_2微晶,采用表面光電壓(SPV)、場(chǎng)致光電壓(FISPV)和瞬態(tài)光電壓(TPV)技術(shù)對(duì)以上光生電荷行為進(jìn)行研究。并通過(guò)部分樣品的光催化MO實(shí)驗(yàn),查找光生電荷行為和光催化結(jié)果的內(nèi)在聯(lián)系。本課題以退火前后PbI_2微晶的制備及性能研究和不同退火時(shí)間對(duì)PbI_2的表面改性兩個(gè)方面來(lái)展開(kāi)的:1、采用溶液法來(lái)制備出PbI_2微晶,禁帶寬度為2.39 eV。PbI_2微晶的表面存在捕獲空穴的表面態(tài),致使亞帶隙光照下光伏反轉(zhuǎn)現(xiàn)象的發(fā)生,對(duì)應(yīng)的表面態(tài)位于價(jià)帶上方0.43 eV。表面光電壓在不同波長(zhǎng)光照下光生電荷產(chǎn)生方式不同,遮光后對(duì)應(yīng)的光電壓衰減時(shí)間也不同,這就導(dǎo)致了不同的MO光催化結(jié)果。2、將PbI_2微晶在520 K真空條件下分別退火10 min、20 min和30 min,退火后樣品的原子配比(Pb:I)更接近1:2。PbI_2微晶在退火后樣品的的光譜吸收范圍有所擴(kuò)展,帶隙隨退火時(shí)間的延長(zhǎng)越來(lái)越大。退火導(dǎo)致表面缺陷減少,但增大了在場(chǎng)致作用下的反型層作用,外加偏壓越大,反型層的作用也逐漸加強(qiáng),甚至超過(guò)了本征的帶帶躍遷作用。
[Abstract]:With the development of society and economy, a series of environmental problems are coming. How to make full use of energy and degrade pollution effectively has become the key to solve the problem. Semiconductor materials with photovoltaic effect and photocatalytic ability become the breakthrough point to solve the problem. The photovoltaic response of semiconductor materials and their participation in photocatalytic process mainly depend on the photocharge separation, migration and recombination process. The photoinduced charge behavior usually occurs on the surface of the semiconductor. The photovoltaic response and photocatalytic efficiency of the semiconductor can be improved by studying the photovoltaic properties of the semiconductor surface. PbIStack2 is a p-type semiconductor material with a wide bandgap of about 2.4 EV. It has many advantages, such as high atomic coefficient, large band gap, high resistivity and great carrier mobility life. It can effectively utilize solar energy and has potential in photovoltaic, detector, sensor and photocatalytic applications. Due to the generation of photogenerated charge, there are few studies on the transport and recombination mechanism, which seriously limits the application of PbIAP2. For the above reasons, surface photovoltage (SPV), field photovoltage (FISPV) and transient photovoltage (TPV) were used to study the photoinduced charge behavior of PbI2 microcrystals before and after annealing. The internal relationship between photocatalytic charge behavior and photocatalytic results was found through the photocatalytic MO experiments of some samples. In this paper, the preparation and properties of PbISAT _ 2 microcrystals before and after annealing and the surface modification of PBI _ s _ 2 by different annealing time were used to prepare PbI-2 microcrystals by solution method. The gap width of 2.39eV.PbI2 microcrystal has a surface state of trapped holes, which results in photovoltaic inversion under sub-band gap illumination. The corresponding surface state is 0.43 EV above the valence band. The photovoltage of surface photovoltage is produced in different ways under different wavelengths of illumination, and the attenuation time of photovoltage after shading is also different. This resulted in different MO photocatalytic results .2.The microcrystals were annealed at 520K vacuum for 10 min ~ 20 min and 30 min, respectively. The atomic ratio (Pb: I) of the annealed samples was closer to 1: 2. The absorption range of PbI _ 2 microcrystals increased after annealing. The band gap increases with the increase of annealing time. Annealing results in the reduction of surface defects, but increases the effect of the inversion layer under the field action. The greater the bias, the stronger the effect of the inversion layer is, even more than the band transition of the intrinsic band.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36

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相關(guān)期刊論文 前1條

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本文編號(hào)：2112855