Lifetime and encapsulation study of organic solar cells (LEOsc)

有机太阳能电池（LEOsc）的寿命和封装研究

• 批准号: EP/X036014/1
• 负责人: Yuanyuan Cao
• 金额: $ 64.93万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX036014%2F1
• 关键词: Lifetime; encapsulation; study; organic; solar

The Paris Agreement set the goal to reach Net-Zero emission by 2050 to tackle global warming; this has stimulated much research into energy transition. Photovoltaic technology receives great attention as it can meet increasing energy demands by converting solar radiation into electricity without greenhouse gas emissions. However, global PV deployment is still low (only 5% of global electricity came from PV technology in 2021) and the market is currently dominated by energy-intensive conventional crystalline silicon PV. To facilitate the energy transition, novel photovoltaic technologies, such as organic solar cells (OSCs), are being intensively studied for flexible & lightweight applications. However, OSCs must fulfil requirements in efficiency, lifetime, and cost for future commercialisation. The cost of OSC production and installation is expected to be very low compared to conventional Si. Continuing developments have been made in improving OSC efficiency and indeed competitive high PCE (power conversion efficiency) of about 20% has been reached so far. While OSC lifetime is still substantially lower than that of inorganic cells and there is much room for improvement. Since OSC degradation is mainly caused by exposure to moisture and oxygen, encapsulation of the cells is one of the most straightforward ways to improve OSC life expectancy. In this context, this Fellowship research focusses on the OSC lifetime study. The proposed tasks involve two aspects, encapsulation layer development and OSC extrinsic degradation mechanism study.Specifically, the atomic layer deposition (ALD) technique will be utilized for the fabrication of the encapsulation layer. ALD is a technique based on the self-limiting reaction between distinct precursors, which can deposit dense thin films with excellent uniformity. The uniformity of the film allows the water and oxygen permeation rate to be extremely low, thus the encapsulation film can protect OSCs longer. The Fellowship will systematically investigate all the encapsulation strategies by the ALD technique, namely: (1) Barrier films for lamination. This strategy allows the possibility of manufacturing the barrier films in advance, then OSCs will be laminated with barrier films. A huge advantage of this scheme is the whole processing of a module can be done in a roll-to-roll configuration and the ALD conditions are not limited by the sensitive organics. (2) Direct thin-film encapsulation (TFE). This strategy is desirable to minimize mechanical stress, abrasion to the barrier, and device contamination. The main issue of TFE is the encapsulation processing conditions are highly constrained by the organics. In both strategies, OSC encapsulation layers with low moisture permeation and sufficient mechanical durability will be developed, an intermediate layer will also be developed to serve as a better growth surface for ALD materials to ensure the thin films are perfect. The deposition rate will be improved to increase the production throughput of ALD. Comparisons of the encapsulation performance within the different strategies will address the best encapsulation configuration for OSCs. Thereafter, the optimal encapsulation will be utilised for the protection of state-of-the-art OSCs, accelerated tests and outdoor lifetime tests will be performed on the protected OSCs to characterise the lifetime. The extrinsic degradation of encapsulated cells will be also studied to address the cell break-down. Optimisation strategies will be given to the encapsulation layers according to the degradation mechanism. My goal is to push the lifetime of the OSC to a comparable level to that of Si. At the end of the Fellowship, scale-up trials will be undertaken with the help of Oxford Physics' Innovation and Enterprise Manager (Phillip Tait) and our industry partners.

《巴黎协定》设定了到2050年实现净零排放的目标，以应对全球变暖；这激发了对能源转型的大量研究。光伏技术受到高度关注，因为它可以通过将太阳辐射转化为电能而不排放温室气体来满足日益增长的能源需求。然而，全球光伏部署仍然较低（2021年全球仅有5%的电力来自光伏技术），且市场目前以能源密集型传统晶硅光伏为主。为了促进能源转型，人们正在深入研究新型光伏技术，例如有机太阳能电池（OSC），以实现灵活和轻量级的应用。然而，OSC 必须满足未来商业化的效率、寿命和成本要求。与传统硅相比，OSC 的生产和安装成本预计非常低。在提高 OSC 效率方面不断取得进展，实际上迄今为止已达到约 20% 的具有竞争力的高 PCE（功率转换效率）。虽然OSC的寿命仍然大大低于无机电池，并且还有很大的改进空间。由于 OSC 降解主要是由于暴露于水分和氧气而引起的，因此电池封装是提高 OSC 预期寿命的最直接方法之一。在此背景下，该奖学金研究的重点是 OSC 寿命研究。所提出的任务涉及封装层开发和OSC外在降解机制研究两个方面。具体来说，将利用原子层沉积（ALD）技术来制造封装层。 ALD 是一种基于不同前驱体之间自限反应的技术，可以沉积具有优异均匀性的致密薄膜。薄膜的均匀性使得水和氧的渗透率极低，因此封装膜可以更长时间地保护OSC。该奖学金将系统地研究 ALD 技术的所有封装策略，即： (1) 用于层压的阻隔膜。这种策略允许提前制造阻挡膜，然后将 OSC 与阻挡膜层压。该方案的一个巨大优势是模块的整个加工可以在卷对卷配置中完成，并且 ALD 条件不受敏感有机物的限制。 (2)直接薄膜封装(TFE)。该策略可最大程度地减少机械应力、屏障磨损和器件污染。 TFE 的主要问题是封装加工条件受到有机物的高度限制。在这两种策略中，都将开发具有低透湿性和足够机械耐久性的OSC封装层，还将开发中间层作为ALD材料更好的生长表面，以确保薄膜的完美。沉积速率将得到提高，以提高 ALD 的生产量。比较不同策略内的封装性能将确定 OSC 的最佳封装配置。此后，将采用最佳封装来保护最先进的OSC，并对受保护的OSC进行加速测试和户外寿命测试，以表征其寿命。还将研究封装细胞的外在降解，以解决细胞分解问题。根据退化机制对封装层给出优化策略。我的目标是将 OSC 的寿命提高到与 Si 相当的水平。在奖学金结束时，将在牛津物理学院创新和企业经理（Phillip Tait）和我们的行业合作伙伴的帮助下进行扩大试验。