3D-Localisation - Three Dimensionally Defined Non-Fullerene Acceptors

太阳光基本上是一种无限的能源。将其转化为电能、热能或化学能是解决能源危机和减少人类活动引起的气候变化影响的最具吸引力和最有效的方法之一。有机太阳能电池是一种新兴技术，可以帮助向可再生经济过渡。它们重量轻、灵活，利用现成的有机分子，与传统的硅器件不同，它们可以通过节能、非热的方法进行加工。这些器件的发展依赖于富勒烯作为电子受体材料。富勒烯是碳的分子形式，具有球形，类似足球的几何形状，这使得电子在整个分子表面产生离域。这种结构赋予富勒烯多种独特的性质，它们可以可逆地接受多达6个电子，并且可以在三维空间中有效地传输电荷。然而，现在已经确定使用富勒烯对有机太阳能电池的性能有严格的限制。富勒烯吸收阳光的能力很差，而且它们参与的过程在运行时对设备具有破坏性。更复杂的是，它们的生产和购买都很昂贵，并且在任何程度的控制下进行化学修饰都极具挑战性。这意味着它们的光学和电子特性不容易调整为太阳能电池或任何其他特定应用。最终，富勒烯的使用是不可持续的，因此，如果这些绿色能源技术要充分发挥其潜力，迫切需要新的非富勒烯受体。该项目全面考察了富勒烯的有益和有害性质，并将利用这种方法生产一类全新的非富勒烯受体。这将对可再生能源的供应产生巨大影响。这种方法有两个关键方面：1)使用三维分子结构作为中心支架。这将促进三维的电子离域。2)通过将选定的杂环侧基附着在这些支架上，可以最大限度地提高太阳能吸收，并且可以很容易地控制这些新分子的电化学和形态特性。这代表了有用的非富勒烯受体发展的一个阶段性变化。将生产用于能量转换技术的新一代分子材料，并将建立一般实现真正类似富勒烯的行为的设计规则，并适用于任何应用。现有的许多有机电子材料的研究工作主要集中在由平面杂环碎片组成的分子和聚合物上，与之相反，在三维空间中探索化学空间是本文提出的工作的关键。这大大增加了我们方法的新颖性。

Sunlight presents an essentially infinite source of energy. Converting it into electricity, heat, or chemical energy is among the most appealing and effective approaches to tackling the energy crisis and reducing the impact of human activity induced climate change. Organic solar cells are one emerging technology that can aid in the transition to a renewable economy. They are lightweight, flexible devices which utilise readily available organic molecules and can be processed by energy-efficient, non-thermal methods unlike traditional silicon devices. The development of these devices has relied upon fullerenes as electron acceptor materials.Fullerenes are molecular forms of carbon with a spherical, soccer ball-like geometry which gives rise to delocalisation of electrons across the entire surface of the molecule. This structure attributes fullerene with a variety of unique properties, they can reversibly accept up to six electrons and can transport charges efficiently in three dimensions. However, it is now well-established that using fullerenes places strict limitations on organic solar cell performance. Fullerenes absorb sunlight only poorly and they participate in processes which are destructive to the device while under operation. Compounding this, they are expensive to produce and purchase, and are extremely challenging to chemically modify with any degree of control. This means that their optical and electronic properties cannot be easily tuned for solar cells or any other specific application. Ultimately, the use of fullerenes is non-sustainable therefore new non-fullerene acceptors are urgently required if these green energy technologies are to realise their full potential.This project takes a holistic view of the beneficial and detrimental properties of fullerenes and will use this approach to produce a completely new class of non-fullerene acceptors. These will serve to impact hugely on the delivery of renewable energy sources. There are two key facets to this approach:1) The use of three-dimensional molecular structures as a central scaffold. These will facilitate electronic delocalisation in three dimensions.2) By attaching selected heterocyclic side groups to these scaffolds, solar absorbance will be maximised, and the electrochemical and morphological properties of these new molecules will be controlled in a facile manner.This represents a step-change in the development of useful non-fullerene acceptors. A new generation of molecular materials for use in energy conversion technologies will be produced, and design rules for attaining truly fullerene-like behaviour in general, and for any application, will be established. In contrast with much of the existing work on organic electronic materials, which focusses upon molecules and polymers composed of planar heterocyclic fragments, exploring chemical space in three dimensions is key to the work proposed here. This adds significantly to the novelty of our approach.