【作者】 王超；

【导师】 武永刚；

【作者基本信息】 河北大学 ， 高分子化学与物理， 2022， 博士

【摘要】 有机太阳能电池具有质轻、制备工艺简单、成本低廉、材料设计丰富多样以及可以大面积制备等优点,受到人们的广泛关注。由电子给体和电子受体组成的活性层是有机太阳能电池的核心结构,其作用是进行光电转换。近年来,研究人员致力于新型给、受体材料的开发和器件工艺的优化,将本体异质结有机太阳能电池的能量转换效率提升到18%,推动了有机太阳能电池的发展。苯并噻二唑是一种具有稠合芳香核的缺电子单元,既可以用作给体材料也可以用作受体材料。以往已经有大量的苯并噻二唑类的光电材料被开发出来,证明了其具有很大的研究价值。本文主要是以苯并噻二唑为核心,设计、合成了几种光伏材料并应用于光伏器件当中,主要的研究内容如下:第一、聚合物太阳能电池凭借其诸多有利优势,在下一代清洁能源领域展现出巨大潜力。在此,我们成功设计并合成了一系列新型含氟苯并噻二唑类共轭共聚物WCP32和WCP36。在AM 1.5G照明下,在约100 nm厚度的有源层内,基于WCP32和WCP36的器件实现了15.5%和6.36%的功率转换效率。15.5%的PCE是所有报道的基于苯并噻二唑类的传统非富勒烯单结聚合物有机太阳能电池的最高值。此外,值得注意的是,该电池采用简单的制造结构,优异的光电性能和良好的溶解性使聚合物WCP32成为高性能聚合物太阳能电池的替代材料。第二、近红外电子受体在有机太阳能电池中发挥着重要作用,其中它们通常可以分为稠环和非稠环电子受体。在这项工作中,我们报道了第一个用于有机太阳能电池的基于萘并双三唑的非稠环电子受体。新受体包含萘并双三唑单元作为核心,环戊二噻吩作为π桥和2-(3-氧代-2,3-二氢茚-1-亚基)丙二腈(IC)作为端基。此外,将两个或四个氟原子引入IC端基以调整受体的物理和结晶特性。发现新受体在携带F原子时表现出300-900 nm范围内的宽吸收光谱和深前沿能级。基于这些受体的有机太阳能电池提供了6.19%-10.79%的PCE,其中基于F的受体表现出更高的PCE,这是由于更好的结晶度、更高的电荷载流子迁移率以及在太阳能电池中的低电荷复合。第三、聚合物受体的开发对于提高全聚合物太阳能电池的功率转换效率至关重要。在这项工作中,我们开发了由苯并噻二唑类非稠环小分子衍生的两种新型聚合物受体WCP30和WCP38,它们具有合成简单、光学禁带窄和高吸收系数,以PBDB-T为给体制备全聚合物有机太阳能电池,溶剂添加剂和热退火的协同作用提高了器件性能。结果,全聚合物电池分别为WCP30和WCP38提供了4.99%和2.08%的PCE。进一步的形态学和电学表征表明,WCP30更高的器件性能源于更有效的激子分离和电荷传输,这是由于固态聚合物堆积更有序。我们的工作表明,聚合非稠环小分子受体是开发高性能全聚合物受体的有效策略。第四、最近,由双缆聚合物制造的单组分有机太阳能电池引起了极大的关注。然而,功率转换效率应进一步提高以满足商业需求。为了改善功率转换效率,相分离和电荷转移特性必须得到很好的控制,因此双缆聚合物的给体聚合物和受体片段应该被精确设计。在这项工作中,合成了两种以苯并噻二唑聚合物为骨架,苝双酰亚胺为侧链的双缆聚合物PBT(t)PBI和PBT(tt)PBI。随后,将这两种聚合物引入到单组分有机太阳能电池中。因此,PBT(t)PBI表现出优异的功率转换效率,高达4.35%,远高于2.35%的PBT(tt)PBI。PBT(t)PBI的优异性能得益于共轭主链和侧链的结晶配合,这有利于构建双连续的空穴和电子传输通道。更多还原

【Abstract】 Organic solar cells have attracted people’s attention because of their advantages such as light weight,simple preparation process,low cost,rich and diverse material design and large-area preparation.The active layer composed of electron donor and electron acceptor is the core structure of organic solar cells,and its function is photoelectric conversion.In recent years,researchers are committed to the development of new donor and acceptor materials and the optimization of device technology,which improves the energy conversion efficiency of bulk heterojunction organic solar cells to 18%and promotes the development of organic solar cells.Benzothiadiazole is an electron-deficient unit with fused aromatic nucleus,which can be used as both donor and acceptor materials.In the past,a large number of benzothiadiazole photoelectric materials have been developed,which proves that they have great research value.In this paper,benzothiadiazole is the core,and several photovoltaic materials are designed and synthesized and applied to photovoltaic devices.The main research contents are as follows:Firstly,polymer solar cells show great potential in the next generation of clean energy because of their many advantages.Here,we have successfully designed and synthesized a series of novel conjugated copolymers WCP32 and WCP36 containing fluorobenzothiadiazole.Under the illumination of AM 1.5G,the devices based on WCP32 and WCP36 achieved power conversion efficiency of 15.5%and 6.36%in the active layer with a thickness of about 100 nm.15.5%PCE is the highest value of all reported traditional non-fullerene single junction polymer organic solar cells based on benzothiadiazoles.In addition,it is worth noting that the cell adopts a simple manufacturing structure,and its excellent photoelectric properties and good solubility make polymer WCP32 a substitute material for high-performance polymer solar cells.Second,near infrared electron acceptors play an important role in organic solar cells,among which they can usually be divided into fused ring and non-fused ring electron acceptors.In this work,we report the first non-fused ring electron acceptor based on naphtho-bis-triazole for organic solar cells.The new receptor contains naphtho-bis-triazole unit as the core,pentodithiophene acts asπbridge and 2-(3-oxo-2,3-indan-1-subunit)malononitrile(IC)acts as terminal group.In addition,two or four fluorine atoms are introduced into the IC terminal group to adjust the physical and crystalline characteristics of the acceptor.It is found that the new receptor exhibits a wide absorption spectrum and a deep front energy level in the range of 300-900 nm when carrying F atoms.Organic solar cells based on these receptors provide 6.19%-10.79%PCE,among them,F-based acceptors show higher PCE,which is due to better crystallinity,higher charge carrier mobility and low charge recombination in solar cells.Thirdly,the development of polymer receptor is very important to improve the power conversion efficiency of all-polymer solar cells.In this work,we have developed two novel polymer aeceptors WCP30 and WCP38 derived from benzothiadiazole non-fused small molecules,which have simple synthesis,narrow optical band gap and high absorption coefficient.All-polymer organic solar cells were prepared with PBDB-T as the donor,and the synergistic effect of solvent additives and thermal annealing improved the device performance.As a result,all-polymer batteries provided 4.99%and 2.08%PCE for WCP30 and WCP38,respectively.Further morphological and electrical characterization shows that the higher device performance of WCP30 is due to more effective exciton separation and charge transport,this is due to the more orderly accumulation of solid polymers.Our work shows that polymerization of non-condensed small molecular aeceptors is an effective strategy to develop high-performance all-polymer receptors.Fourthly,recently,single-component organic solar cells made of double-cable polymer have attracted great attention.However,the power conversion efficiency should be further improved to meet the commercial demand.In order to improve the power conversion efficiency,the phase separation and charge transfer characteristics must be well controlled,Therefore,the donor polymer and acceptor segments of the double-cable polymer should be precisely designed.In this work,two kinds of double-cable polymers PBT(t)PBI and PBT(tt)PBI with benzothiadiazole polymer as skeleton and perylene diimide as side chain were synthesized.Subsequently,these two polymers were introduced into single-component organic solar cells.Therefore,PBT(t)PBI shows excellent power conversion efficiency,up to4.35%,Much higher than 2.35%PBT(tt)PBI.The excellent performance of PBT(t)PBI is due to the crystallization coordination of conjugated main chain and side chain,which is conducive to the construction of bicontinuous hole and electron transmission channels.更多还原