基于非對(duì)稱光柵導(dǎo)模共振提高有機(jī)太陽能電池吸收效率的研究
發(fā)布時(shí)間：2018-09-12 18:58
【摘要】：有機(jī)太陽能電池(Organic Solar Cells,OSCs)由于其材料廉價(jià)、柔韌性和成膜性都較好、可低溫操作以及可根據(jù)需要對(duì)分子進(jìn)行修飾等特性,近年來,一直成為研究的熱點(diǎn)。雖然有機(jī)材料易于制備,但是其較短的載流子擴(kuò)散距離使得活性層的厚度較大時(shí)會(huì)降低的載流子收集效率,這一矛盾限制了OSCs器件的吸收,使得OSCs轉(zhuǎn)換效率很低。近年來,有很多研究致力于改變OSCs的內(nèi)部結(jié)構(gòu)以提高活性層對(duì)入射光的捕獲能力。在OSCs器件結(jié)構(gòu)中引入金屬納米材料是一種行之有效的方法,例如,在OSCs中引入周期性金屬光柵或在活性層中添加金屬納米顆粒,通過在金屬與有機(jī)材料活性層界面形成表面等離子激元,并在局部區(qū)域形成較強(qiáng)的電磁場(chǎng)分布,從而能夠很大程度提高活性層對(duì)光的吸收。但是將金屬納米結(jié)構(gòu)與有機(jī)活性層直接接觸時(shí),金屬材料會(huì)對(duì)光生載流子有一定的吸收,同時(shí)也會(huì)產(chǎn)生熱電子輻射,因此活性層的吸收效率會(huì)受到一定的影響。另一方面,在含有一維金屬納米光柵的OSCs器件中,表面等離子激元只有在TM(橫磁場(chǎng))偏振的入射光下才能激發(fā),而對(duì)于TE(橫電場(chǎng))偏振的入射光,吸收效率并沒有明顯的提高。本論文提出采用電介質(zhì)材料構(gòu)成非對(duì)稱光柵來實(shí)現(xiàn)OSCs器件吸收效率的提高,具體光柵結(jié)構(gòu)主要由作為活性層的P3HT:PCBM和作為電子傳輸層的PEDOT:PSS材料構(gòu)成。該結(jié)構(gòu)能夠避免因?yàn)榻饘俨牧蠈?duì)光生載流子的吸收而產(chǎn)生損耗。在電介質(zhì)材料構(gòu)成的光柵結(jié)構(gòu)中,通過采用合適參數(shù)的衍射光學(xué)元件和波導(dǎo)層的薄膜結(jié)構(gòu)使得衍射光場(chǎng)與受調(diào)制波導(dǎo)泄露模之間耦合引起能量重新分布,從而在波導(dǎo)層產(chǎn)生場(chǎng)強(qiáng)增強(qiáng)的導(dǎo)模共振現(xiàn)象,這種近場(chǎng)的增強(qiáng)能夠促進(jìn)活性層材料的光的吸收。同時(shí),非對(duì)稱光柵能夠打破對(duì)稱光柵中的簡(jiǎn)并模式,在考察的波長(zhǎng)范圍為內(nèi)產(chǎn)生更多的波導(dǎo)模式,從而提高OSCs器件的吸收效率的寬譜特性。本文主要研究?jī)?nèi)容:(1)簡(jiǎn)述OSCs的發(fā)展背景和意義,介紹其工作原理、以及影響OSCs活性層的吸收效率的因素。(2)介紹亞波長(zhǎng)光柵特性,即導(dǎo)模共振異�，F(xiàn)象。闡述導(dǎo)模共振異常的激發(fā)原理,及如何運(yùn)用時(shí)域有限差分法在TE(橫電場(chǎng))和TM(橫磁場(chǎng))偏振模式進(jìn)行電磁場(chǎng)分析。(3)第三章提出一種基于T型非對(duì)稱二元光柵陷光結(jié)構(gòu)的OSCs器件。分析發(fā)現(xiàn),T型對(duì)稱光柵結(jié)構(gòu)中,光柵結(jié)構(gòu)的周期P對(duì)對(duì)稱光柵模式的位置和模式的變化起主要作用。在TE偏振模式下,在400~800 nm范圍內(nèi),與對(duì)稱結(jié)構(gòu)相比,與對(duì)稱結(jié)構(gòu)相比,含有2個(gè)光柵脊的非對(duì)稱光柵結(jié)構(gòu)整體平均吸收效率提高了4.2%。與其相比,當(dāng)非對(duì)稱光柵結(jié)構(gòu)中光柵脊的個(gè)數(shù)為3個(gè)時(shí),整體平均吸收效率提高了約52%。(4)在第三章基礎(chǔ)上,提出核殼-ITO非對(duì)稱光柵結(jié)構(gòu)的OSCs器件,發(fā)現(xiàn)核殼-ITO非對(duì)稱光柵相比較T型光柵結(jié)構(gòu),導(dǎo)模形成的在有機(jī)活性層材料中的局域場(chǎng)分布更有利于器件吸收效率的提高。
[Abstract]:Organic solar cell (Organic Solar Cells,OSCs) has been a hot research area in recent years because of its cheap materials, good flexibility and film-forming properties, low temperature operation and modification of molecules as needed. Although organic materials are easy to prepare, the short carrier diffusion distance reduces the carrier collection efficiency when the thickness of the active layer is larger, which limits the absorption of OSCs devices and makes the conversion efficiency of OSCs very low. In recent years, many studies have been devoted to changing the internal structure of OSCs to improve the ability of the active layer to capture incident light. It is an effective method to introduce metal nanomaterials into the structure of OSCs devices, for example, to introduce periodic metal gratings in OSCs or to add metal nanoparticles to active layers. Through the formation of surface plasmon at the interface of the active layer of metal and organic materials and the formation of strong electromagnetic field distribution in the local region, the absorption of light in the active layer can be greatly improved. However, when the metal nanostructure is directly contacted with the organic active layer, the metal material will absorb the photogenerated carriers and generate hot electron radiation, so the absorption efficiency of the active layer will be affected to a certain extent. On the other hand, in OSCs devices containing one-dimensional metal nanocrystalline gratings, the surface plasma excitations can only be excited under the polarized incident light of TM (transverse magnetic field), but for the incident light polarized by TE (transverse electric field), the absorption efficiency is not significantly improved. In this paper, an asymmetric grating based on dielectric material is proposed to improve the absorption efficiency of OSCs devices. The grating structure is mainly composed of P3HT:PCBM as the active layer and PEDOT:PSS as the electron transport layer. The structure can avoid loss due to the absorption of photogenerated carriers by metal materials. In the grating structure of dielectric material, the coupling between the diffractive light field and the leaky mode of the modulated waveguide is caused by the appropriate parameters of the diffractive optical element and the thin film structure of the waveguide layer, which results in the redistribution of the energy. Thus the guided mode resonance in the waveguide layer is enhanced by the field intensity, and the near field enhancement can promote the light absorption of the active layer material. At the same time, the asymmetric grating can break the degenerate mode in the symmetric grating and generate more waveguide modes in the wavelength range of investigation, so as to improve the absorption efficiency of OSCs devices. The main contents of this paper are as follows: (1) the development background and significance of OSCs, its working principle and the factors affecting the absorption efficiency of the active layer of OSCs are introduced. (2) the characteristics of subwavelength grating, that is, the anomalous phenomenon of guided mode resonance, are introduced. The excitation principle of guided mode resonance anomaly and how to analyze the polarization mode of TE (transverse electric field) and TM (transverse magnetic field) by using finite-difference time-domain method are described. (3) in chapter 3, a novel OSCs device based on T-type asymmetric binary grating trapping structure is proposed. It is found that the periodic P of the grating structure plays a major role in the position and mode change of the symmetric grating mode in the structure of T type symmetric grating. In the polarization mode of TE, the average absorption efficiency of asymmetric grating structure with two ridges is increased by 4.2% compared with symmetric structure in the range of 400,800 nm. Compared with the asymmetric grating structure, when the number of grating ridges is 3, the overall average absorption efficiency is improved by about 52. (4) based on the third chapter, a core-shell OSCs device with asymmetric grating structure is proposed. It is found that the local field distribution of core-shell ITO asymmetric gratings in organic active layer materials is more favorable to the increase of absorption efficiency than that of T-type gratings.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM914.4
本文編號(hào)：2239933
[Abstract]:Organic solar cell (Organic Solar Cells,OSCs) has been a hot research area in recent years because of its cheap materials, good flexibility and film-forming properties, low temperature operation and modification of molecules as needed. Although organic materials are easy to prepare, the short carrier diffusion distance reduces the carrier collection efficiency when the thickness of the active layer is larger, which limits the absorption of OSCs devices and makes the conversion efficiency of OSCs very low. In recent years, many studies have been devoted to changing the internal structure of OSCs to improve the ability of the active layer to capture incident light. It is an effective method to introduce metal nanomaterials into the structure of OSCs devices, for example, to introduce periodic metal gratings in OSCs or to add metal nanoparticles to active layers. Through the formation of surface plasmon at the interface of the active layer of metal and organic materials and the formation of strong electromagnetic field distribution in the local region, the absorption of light in the active layer can be greatly improved. However, when the metal nanostructure is directly contacted with the organic active layer, the metal material will absorb the photogenerated carriers and generate hot electron radiation, so the absorption efficiency of the active layer will be affected to a certain extent. On the other hand, in OSCs devices containing one-dimensional metal nanocrystalline gratings, the surface plasma excitations can only be excited under the polarized incident light of TM (transverse magnetic field), but for the incident light polarized by TE (transverse electric field), the absorption efficiency is not significantly improved. In this paper, an asymmetric grating based on dielectric material is proposed to improve the absorption efficiency of OSCs devices. The grating structure is mainly composed of P3HT:PCBM as the active layer and PEDOT:PSS as the electron transport layer. The structure can avoid loss due to the absorption of photogenerated carriers by metal materials. In the grating structure of dielectric material, the coupling between the diffractive light field and the leaky mode of the modulated waveguide is caused by the appropriate parameters of the diffractive optical element and the thin film structure of the waveguide layer, which results in the redistribution of the energy. Thus the guided mode resonance in the waveguide layer is enhanced by the field intensity, and the near field enhancement can promote the light absorption of the active layer material. At the same time, the asymmetric grating can break the degenerate mode in the symmetric grating and generate more waveguide modes in the wavelength range of investigation, so as to improve the absorption efficiency of OSCs devices. The main contents of this paper are as follows: (1) the development background and significance of OSCs, its working principle and the factors affecting the absorption efficiency of the active layer of OSCs are introduced. (2) the characteristics of subwavelength grating, that is, the anomalous phenomenon of guided mode resonance, are introduced. The excitation principle of guided mode resonance anomaly and how to analyze the polarization mode of TE (transverse electric field) and TM (transverse magnetic field) by using finite-difference time-domain method are described. (3) in chapter 3, a novel OSCs device based on T-type asymmetric binary grating trapping structure is proposed. It is found that the periodic P of the grating structure plays a major role in the position and mode change of the symmetric grating mode in the structure of T type symmetric grating. In the polarization mode of TE, the average absorption efficiency of asymmetric grating structure with two ridges is increased by 4.2% compared with symmetric structure in the range of 400,800 nm. Compared with the asymmetric grating structure, when the number of grating ridges is 3, the overall average absorption efficiency is improved by about 52. (4) based on the third chapter, a core-shell OSCs device with asymmetric grating structure is proposed. It is found that the local field distribution of core-shell ITO asymmetric gratings in organic active layer materials is more favorable to the increase of absorption efficiency than that of T-type gratings.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM914.4
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 陳樂;王慶康;沈向前;陳文;黃X;劉代明;;Absorption enhancement in thin film a-Si solar cells with double-sided SiO_2 particle layers[J];Chinese Physics B;2015年10期
2 劉瑞遠(yuǎn);孫寶全;;有機(jī)物/硅雜化太陽能電池的研究進(jìn)展[J];化學(xué)學(xué)報(bào);2015年03期
，本文編號(hào)：2239933
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