Singlet Fission Photon Multipliers - Adding Efficiency to Silicon Solar Cells

太阳能可以为全球能源供应做出重大贡献，但这种可再生能源要想产生重大影响，就需要在成本上与传统能源竞争。硅太阳能电池是现有的光伏技术，在过去的5-8年里，它受益于制造成本的大幅降低。现在模块成本不再是已安装系统成本的最大组成部分，进一步降低每安装瓦特成本需要提高电池效率。然而，像硅这样的单结电池从根本上受到这样一个事实的限制，即超过半导体带隙能量的太阳光谱能量会随着热量的损失而损失。我们的目标是开发一种简单的活性薄膜，可以应用于硅(或任何其他)太阳能电池的前表面，从而将电池效率提高高达4%(例如，从20%到24%)。我们将通过捕获太阳光谱中的高能光子并将其转化为两个低能光子来实现这一点，这些光子可以被太阳能电池吸收，而不会因热而损失能量。这将通过发生在某些有机材料中的单重态激子裂变过程来实现，将光子吸收产生的自旋为0的单重态转换为两个自旋为1的三重态。我们最近证明了将这些非发射的三重态转移到无机半导体纳米粒子上是可能的，然后它可以有效地发射光子，这些光子可以被底层的太阳能电池吸收。在这个项目中，我们将基于上述方法优化、设计和演示光子倍增薄膜，为硅太阳能电池提供低成本的效率增强，无需重新设计电池的电气结构。

Solar energy can make a major contribution to global energy supply, but for this renewable energy source to make a major impact it will need to compete on cost with conventional sources of energy. Silicon solar cells are the incumbent photovoltaic technology, and have benefited from huge reductions in manufacturing costs over the last 5-8 years. Now that the module cost is no longer the largest component of the installed system cost, further reductions in the cost per installed Watt require increases in the cell efficiency. However, single-junction cells such as silicon are fundamentally limited by the fact that the energy of the solar spectrum in excess of the semiconductor bandgap energy is lost as heat.We aim to develop a simple active film that can be applied to the front surface of a silicon (or any other) solar cell that will increase the cell efficiency by up to 4% (e.g. from 20% to 24%). We will do this by capturing the high-energy photons from the solar spectrum and converting them to two lower-energy photons that can be absorbed in the solar cell without energy losses to heat. This will be achieved using the process of singlet exciton fission which occurs in certain organic materials, converting the spin-0 singlet state produced by photon absorption into two spin-1 triplet states. We have very recently demonstrated that it is possible to transfer these non-emissive triplet states onto inorganic semiconductor nanoparticles, which can then efficiently emit photons that could be absorbed by an underlying solar cell.In this project, we will optimise, engineer and demonstrate photon multiplier films based on the approach described above, providing a low-cost efficiency enhancement for silicon solar cells that can be implemented without re-engineering of the electrical structure of the cell.