界面修饰层对有机太阳能电池的性能影响研究

发布时间：2018-09-12 06:19

【摘要】：有机太阳能电池具有制备工艺简单、可以制备于柔性基板上、便携性高、制备成本低廉、可以大面积成膜等优势,在环境问题日益严重的今天受到了越来越多的关注,并且在近二十年来获得了迅猛地发展。但是目前仍因能量转换效率低下、寿命较低、物理机理不明确等问题无法投入商业化应用。而界面修饰层是影响有机太阳能电池能量转换效率、寿命及器件稳定性的重要因素,本论文以提高器件的能量转换效率为主要目的,从器件结构设计、界面修饰层优化方面入手,系统地研究了界面修饰层对器件转换效率的影响。本论文可分为以下四个方面的主要研究内容:(1)研究了Mg:Ca:Al合金阴极小分子有机太阳能电池,通过改变合金阴极中金属Mg的掺杂比例对器件性能进行优化,再对优化过合金阴极的器件改变阴极缓冲层BPhen的厚度,研究BPhen作为阴极缓冲层对器件性能的影响,发现BPhen的引入在活性层与金属阴极之间形成了良好的接触,有效提高了电子的传输效率以及阴极对其收集效率,同时降低了光生激子的猝灭,有效提高了器件的能量转换效率,当BPhen薄膜厚度为10 nm时,器件获得最大能量转换效率0.96%,比未添加阴极缓冲层的器件提高了88.24%,此时器件的开路电压为0.34 V,短路电流为6.90 mA·cm-2,填充因子为0.41。(2)研究了CuPc:C60及NPB:C60结构体异质结有机太阳能电池,与同结构平面异质结器件进行了对比,实验结果表明体异质结器件的性能较平面异质结器件有较大幅度提高,通过改变CuPc及NPB的掺杂比例对器件结构进行了优化,并研究BPhen作为阴极缓冲层对器件性能的影响。研究表明BPhen作为阴极缓冲层起到了阻挡激子的作用,降低了光生载流子猝灭的几率,有效地提高了器件性能。其中,对于CuPc/CuPc:C60/C60结构的体异质结器件,引入阴极缓冲层BPhen后器件的能量转换效率由0.28%提高到了0.63%;对于CuPc/NPB:C60/C60结构的器件,能量转换效率由0.24%提高到了0.40%。(3)研究了引入阴极缓冲层Alq3的有机太阳能电池。通过实验验证了Alq3具有很好的电子传输能力,并且因为其作为阴极缓冲层的引入使活性层与金属阴极间形成了良好的接触,提高了电子载流子的传输效率,增加了器件的能量转换效率。实验结果显示,在Alq3薄膜厚度为3 nm时,器件的能量转换效率达到0.48%,相比于没有阴极缓冲层的同结构器件,引入了Alq3后器件的能量转换效率提高了71.4%,该器件的开路电压为0.25 V,短路电流为4.03 mA·cm-2,填充因子为0.47。(4)研究了NPB、MoO3及V2O5作为阳极缓冲层的ITO/Cu Pc/CuPc:C60/C60/BPhen/Al结构的小分子有机太阳能电池。实验结果表明,NPB及MoO3的引入非但没有提高器件性能反而影响了器件的能量转换效率。而V2O5作为阳极缓冲层时,由于经过V2O5修饰后降低了ITO表面粗糙度,有利于其与活性层之间形成良好的欧姆接触,从而提高了器件的开路电压。同时,V2O5作为阳极缓冲层有效地抑制了漏电流,降低了载流子的复合概率,从而提高了器件的短路电流。实验结果显示,当V2O5薄膜厚度为5 nm时,器件获得最大能量转换效率0.79%,比为添加阳极缓冲层的同结构器件提高了25.4%。
[Abstract]:Organic solar cells have many advantages, such as simple preparation process, high portability, low cost, and large-area film-forming. They have attracted more and more attention in the environment today, and have been developed rapidly in the last two decades. However, they are still inefficient in energy conversion. The interface modification layer is an important factor affecting the energy conversion efficiency, lifetime and device stability of organic solar cells. The main purpose of this paper is to improve the energy conversion efficiency of devices. The effects of interfacial modification layers on the conversion efficiency of the devices are studied systematically in this paper. The main research contents can be divided into the following four aspects: (1) Small molecule organic solar cells with Mg:Ca:Al alloy cathode are studied. The device performance is optimized by changing the doping ratio of Mg in the alloy cathode, and the device with optimized superalloy cathode is modified. The influence of BPhen as cathode buffer layer on device performance was studied. It was found that the introduction of BPhen formed a good contact between the active layer and the metal cathode, which effectively improved the transmission efficiency of electrons and the cathode collection efficiency. At the same time, the quenching of photoexcitons was reduced and the energy of the device was improved. When the thickness of BPhen film is 10 nm, the maximum energy conversion efficiency of the device is 0.96%, which is 88.24% higher than that of the device without cathode buffer layer. At this time, the open circuit voltage is 0.34 V, the short circuit current is 6.90 mA. cm-2, and the filling factor is 0.41. (2) The CuPc: C60 and NPB: C60 heterojunction organic solar cells are studied. The experimental results show that the performance of bulk heterojunction device is much better than that of planar heterojunction device. The structure of the device is optimized by changing the doping ratio of CuPc and NPB. The effect of BPhen as cathode buffer layer on the performance of the device is studied. Buffer layer acts as a barrier to excitons, reduces the probability of photogenerated carrier quenching and effectively improves the device performance. For bulk heterojunction devices with CuPc/CuPc:C60/C60 structure, the energy conversion efficiency is increased from 0.28% to 0.63% by introducing cathode buffer layer BPhen; for CuPc/NPB:C60/C60 structure, the energy conversion efficiency is increased from 0.28% to 0.63%. (3) Organic solar cells with cathode buffer layer Alq3 were studied. The experimental results show that Alq3 has good electron transfer ability, and because of its introduction as cathode buffer layer, the active layer contacts with metal cathode, and the electron carrier transfer efficiency is improved. The experimental results show that when the thickness of Alq3 film is 3 nm, the energy conversion efficiency of the device is 0.48%. Compared with the same structure device without cathode buffer layer, the energy conversion efficiency of the device is improved by 71.4%. The open-circuit voltage of the device is 0.25 V, the short-circuit current is 4.03 mA cm-2 and the filling current is 4.03 mA cm-2. Factor 0.47. (4) A small molecular organic solar cell with ITO/Cu Pc/CuPc:C60/C60/BPhen/Al structure with NPB, MoO_3 and V2O5 as anode buffer layers was studied. The experimental results show that the introduction of NPB and MoO_3 not only improves the performance of the device, but also affects the energy conversion efficiency of the device. The surface roughness of ITO decreases, which is beneficial to the formation of good ohmic contact between ITO and active layer, thus increasing the open-circuit voltage of the device. At the same time, as an anode buffer layer, V2O5 effectively suppresses the leakage current, reduces the probability of carrier recombination, and thus improves the short-circuit current of the device. At 5 nm, the maximum energy conversion efficiency of the device is 0.79%, which is 25.4% higher than that of the same structure device with anode buffer layer.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4

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