Variable temperature double-optical-modulation apparatus

由于我们面临着日益减少的化石燃料世界储量和日益增加的温室气体排放造成的环境危机，收集太阳能是本世纪的一项关键努力。太阳能电池技术目前是以硅为基础的。用于人类能源消耗的设备产生的太阳能转换效率约为10%，这足以满足工业化世界的很大一部分能源需求，但制造这样的设备成本太高，并产生温室气体。为了收回这些能源成本，需要长达四年的连续运行。这是设备寿命的很大一部分；考虑到硅太阳能电池的加工成本，这是该技术广泛应用的一个严重障碍。为了使太阳能对我们的能源需求产生更大的影响，我们需要找到替代技术，减少能源回收期和设备处理成本。这个研究项目的重点是共轭聚合物，它现在提供了一种技术上可行的可溶液加工的成膜半导体。有机光电二极管（opvd）目前作为该技术的候选器件受到相当大的兴趣。在过去十年中开发的最好的材料显示出前景，但在太阳能照明下，OPVD功率转换效率目前被许多研究小组常规测量，限制在5%。对电子动力学的详细了解是超越这一效率极限的关键。我们的目标是测量有机太阳能电池电子应用中重要的过程。我们将通过用一个光电调制的、可调谐的光源诱导光吸收，并测量由泵浦光诱导的光电调制探针光源通过样品的光透射率的非常小的变化，作为温度和调制频率的函数来实现。了解这些令人兴奋的新材料中的电子过程对于有机电子学的进一步发展至关重要，而不仅仅是材料和器件参数的增量优化。

Harvesting solar energy is a key endeavour for this century as we face ever-decreasing fossil fuel world reserves and ever-increasing environmental crises emanating from greenhouse gas production. Solar cell technology is currently based on silicon. Devices used for human energy consumption yield solar power conversion efficiencies of around 10%, which is sufficient to meet a significant fraction of energy demands in the industrialised world, but manufacturing such devices costs too much energy and produces greenhouse gases. In order to recover such energetic costs, up to four years of continuous operation are required. This is a significant fraction of the device lifetime; given the processing costs of silicon solar cells, it represents a serious obstacle to widespread implementation of this technology. In order for solar energy to have a more substantial impact on our energy requirements, we need to find alternative technologies that reduce energy payback periods and device processing costs. This research programme focuses on conjugated polymers, which now provide a technologically viable class of solution-processable, film-forming semiconductors. Organic photovoltaic diodes (OPVDs) currently receive considerable interest as candidate devices for this technology. The best materials that have been developed over the last decade show promise but OPVD power conversion efficiencies under solar illumination, measured routinely by numerous research groups, are currently limited to 5%. Detailed understanding of electronic dynamics is critical to surpass this efficiency limit. Our objectives are to measure processes that are important in electronic applications of organic solar cells. We will do so by inducing optical absorption with a photomodulated, tunable light source, and measuring very small changes in the optical transmittance of a photomodulated probe light source through the sample, induced by the pump light, as a function of temperature and modulation frequency. Understanding electronic processes in these new and exciting materials is essential for further development of organic electronics beyond incremental optimisation of materials and device parameters.