基于染料分子掺杂ZnO的光电导阴极界面研究

发布时间：2018-07-13 15:52

【摘要】：有机太阳电池作为一种能低成本获取太阳能的潜在技术,正受到越来越广泛的关注。目前实验室报道的有机太阳电池最高能量转换效率已经超过10%,达到了工业化生产对于效率的最低要求。但是实验室中制备有机太阳电池的最优条件并不适用于工业化生产。造成这种现象的最重要的一点就是目前实验室制备的有机太阳电池各功能层的厚度非常薄,尤其是界面一般只有2~30 nm,而工业上无法通过印刷技术大规模生产如此薄而又均匀的薄膜。为了解决这一问题,本论文提出光电导界面概念并且系统地研究了这类界面提高有机太阳电池性能的机理以及界面厚度对器件性能的影响,为设计适合于工业化生产的高性能界面薄膜提供实验和理论依据。本论文的工作主要分为四个部分。第一部分工作中,我们使用ZnO/PBI-H双层界面结构制备阴极界面,并成功地应用于有机太阳电池器件中,获得了优异的能量转换效率。PBI-H的修饰能有效降低ZnO的功涵,并且能改善Zn O与活性层之间的接触。特别是热处理后,Zn O与PBI-H之间形成的N-Zn化学键增强了双层界面间的结合,这有利于电子从PBI-H向ZnO的传输,最终使得基于PTB7:PC71BM活性层的器件获得高达9.43%的能量转换效率。此外,我们这种双层界面结构阴极界面适用于不同的材料体系中,使P3HT:PC61BM的能量转换效率从3.51%提升到4.78%,PTB7-Th:PC71BM的能量转换效率从8.33%提升到10.31%)。第二部分工作中,我们使用有机染料分子掺杂ZnO来制备光电导阴极界面并应用于倒置有机太阳电池,大幅度提高器件的能量转换效率。其中有机染料分子的掺杂浓度只有1%,所以这种界面只吸收很少量的光子,却具有极高的电导率。以ZnO:PBI-H薄膜为例,在有机太阳电池测试的条件下具有4.5×10-3S/m的电导率,并且PBI-H的掺杂还能提高ZnO薄膜的电子迁移率和降低其功函数。基于ZnO:PBI-H光电导界面的器件获得了高达10.5%的能量转换效率(活性层PTB7-Th:PC71BM)。更为重要的是,由于ZnO:PBI-H光电导界面高的电导率,其厚度在30~60 nm变化时,器件性能的变化很小。这种厚度不敏感的界面对于未来的工业化生产是至关重要的。我们使用另外的染料分子TCPP掺杂ZnO也获得了光电导界面,证明了光电导阴极界面是可以通过多种有机染料分子掺杂来实现的。第三部分工作中,我们将水溶性傒酰亚胺衍生物PBI-Py掺杂到ZnO中,发展了一种水溶液加工的光电导阴极界面。光诱导的电子转移为阴极界面带来了几个方面的优势,包括显著增加的电导率与电子迁移率以及降低功函,这是一个高性能的阴极界面至关重要的性质。这些对于改善电荷传输性质与功函的新机理将可能引导新一代界面材料的发展。由于ZnO:PBI-Py光电导阴极界面的高电导率和活性层的高迁移率,即使当阴极界面与活性层的厚度分别达到100 nm与300 nm时,基于ZnO:PBI-Py光电导阴极界面与FBT-Th4(1,4):PC71BM活性层的倒置有机太阳电池仍然表现了超过10%的平均能量转换效率。我们的结果清晰地展示了环境友好的加工方法与器件性能对厚度不敏感高效有机太阳能电池结合的可能性,这为有机太阳电池向大规模生产迈进了一大步。第四部分工作中,我们将光电导阴极界面的应用扩展到三元共混体系并且构筑了一个新的高效率三元共混体系使用近红外吸收的小分子和高性能的窄带隙材料。在小分子DPPEZnP-TEH的含量在10%到70%之间时都观察到了三元共混体系相对于二元参比器件能量转换效率的提升。这种高成分容忍性在三元共混体系中是独特的并且能量效率超过11%在三元共混体系中也是仅有的一例。DPPEZnP-TEH的引入降低了器件中的复合并且提高了载流子的分离和传输,从而极大地提高了短路电流密度和填充因子。我们的结果清晰地展示出光电导阴极界面在三元共混有机太阳电池这一新兴领域的巨大潜力。
[Abstract]:Organic solar cells are being paid more and more attention as a potential technology for obtaining solar energy at low cost. The highest energy conversion efficiency of organic solar cells in the laboratory has already exceeded 10%, which has reached the minimum requirement for efficiency in industrial production. But the optimal conditions for the preparation of organic solar cells in the laboratory are the best. It is not suitable for industrial production. The most important part of this phenomenon is that the thickness of the functional layers of the organic solar cells is very thin at present, especially the interface is only 2~30 nm, and the thin and uniform film can not be produced on large scale by printing technology. In order to solve this problem, this theory is discussed. This paper presents the concept of photoconductive interface and systematically studies the mechanism of this kind of interface to improve the performance of organic solar cells and the effect of interface thickness on the performance of the device. It provides experimental and theoretical basis for the design of high performance interface films suitable for industrial production. The work of this paper is divided into four parts. We use the ZnO/PBI-H double layer interface to prepare the cathode interface and successfully used in organic solar cell devices. The excellent energy conversion efficiency.PBI-H can effectively reduce the power culvert of ZnO and improve the contact between the Zn O and the active layer. Especially after the heat, the N-Zn chemical bond between Zn O and PBI-H increases. It is better to combine the double layer interface, which is beneficial to the transmission of the electron from PBI-H to the ZnO, eventually making the devices based on the PTB7:PC71BM active layer get up to 9.43% energy conversion efficiency. In addition, our double layer interface structure cathode interface is suitable for different material systems, and the energy conversion efficiency of P3HT:PC61BM is raised from 3.51% to 4.78%. The energy conversion efficiency of PTB7-Th:PC71BM is increased from 8.33% to 10.31%. In the second part, we use the organic dye molecules doped ZnO to prepare the photoconductive cathode interface and apply it to the inverted organic solar cell, which greatly improves the energy conversion efficiency of the devices. The doping concentration of organic dye molecules is only 1%, so this interface is the interface of the organic dye molecules. Only a very small amount of photon is absorbed, but it has very high conductivity. Taking ZnO:PBI-H film as an example, the conductivity of an organic solar cell is 4.5 x 10-3S/m under the condition of an organic solar cell test, and the doping of PBI-H can improve the electron mobility of the ZnO film and reduce its function function. The device based on the ZnO:PBI-H photoconductive interface has obtained a high of 10.5% energy. The conversion efficiency (active layer PTB7-Th:PC71BM) is more important because, due to the high conductivity of the ZnO:PBI-H photoconductivity interface, the change of the device performance is very small when the thickness of the 30~60 nm changes. The insensitive interface of this thickness is very important for the future industrial production. We use the other dye molecule TCPP doped ZnO to obtain it. The photoconductive interface has proved that the photoconductive cathode interface can be doped by a variety of organic dye molecules. In the third part, we doped the water-soluble imide derivative PBI-Py into ZnO, and developed a photoconductive cathode interface for the processing of aqueous solution. The advantages, including a significant increase in electrical conductivity and electron mobility and the reduction of work functions, are the essential properties of a high performance cathode interface. These new mechanisms for improving charge transfer properties and work letters will lead to the development of a new generation of interface materials. The high conductivity of the ZnO:PBI-Py photoconductive cathode interface. The high mobility of the active layer, even when the thickness of the cathode interface and the active layer reached 100 nm and 300 nm respectively, the inverted organic solar cell based on the ZnO:PBI-Py photoconductive cathode interface and the FBT-Th4 (1,4): PC71BM active layer still showed more than 10% average energy conversion efficiency. Our results clearly show the environmentally friendly processing. In the fourth part of the work, we extend the application of the photoconductive cathode interface to the three element blend system and build a new high efficiency three element blend system. Small molecules of infrared absorption and high performance narrow band gap materials. The energy conversion efficiency of the three element blends relative to the two element ratio is observed at a content of 10% to 70% of the small molecule DPPEZnP-TEH. This high component tolerance is unique in the three element blend and the energy efficiency is more than 11% in three Yuan blending. The only example in the system is the introduction of.DPPEZnP-TEH, which reduces the composition of the device and improves the separation and transmission of the carrier, thus greatly improving the short circuit current density and filling factor. Our results clearly show the great potential of the photoconductive cathode interface in the emerging field of three yuan blends of the machine solar cell.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ132.41;TM914.4

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