Light Trapping in charge transfer states for improved organic photovoltaic performance

电荷转移状态下的光捕获可改善有机光伏性能

• 批准号: 1804690
• 负责人: Adam Moule
• 金额: $ 37.5万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1804690&HistoricalAwards=false
• 关键词: Light; Trapping; charge; transfer; states

Photovoltaics (PVs) convert sunlight directly into electricity without any production of greenhouse gases. Most commercial PVs are made from silicon, which is expensive to process, heavy to transport, and brittle. This fundamental research project contributes to the development of PV devices that are made from organic materials that are low-cost, light-weight, and mechanically flexible. One issue for all PV devices is that the sunlight must be absorbed and not reflected from the surface for any angle of incidence on the surface. This problem has been addressed for silicon PV devices by roughening the front and back surfaces of the silicon in a specific pattern to cause the light to be absorbed into the silicon instead of being reflected back to space. This research project addresses a similar process to roughen the back surface of the organic PV layer to enhance absorption of light specifically in the near infrared portion of the solar spectrum, which contains a large proportion of the solar energy. Through this surface roughening process, the efficiency of organic PV devices will be increased, making them a better commercial option for clean energy production. The pattern will also make the organic PV absorb light more efficiently at high incidence angles, which is similar to sunlight in the morning and evening. Undergraduate and Ph.D. graduate students will be trained with research skills that are valued in the solar, polymer, and semiconducting industries. Student recruiting and outreach activities are designed to enhance inclusion of underrepresented minorities in research science.There is a critical need to engineer light‐trapping structures into organic photovoltaic (OPV) devices that can greatly increase the charge‐transfer (CT) state absorbance in the near infrared (NIR). The goal of this project is to enhance CT‐state absorbance in OPV devices using lateral light‐trapping structures. The overall objective is to develop a roll‐to‐roll (R2R) compatible optical patterning process to scribe lateral light‐trapping structures into OPV layers that can increase the external quantum efficiency (EQE) of CT‐state absorbance above 20% across a broad wavelength range. The central hypothesis of this project is that 700‐1000 nm 2D lateral patterning of the OPV layer combined with a thick active layer will achieve this goal of 20% EQE in the CT‐states. The rationale that underlies the research is to mimic light‐trapping structures used in inorganic thin‐film PV devices using solution processing methods that make OPV potentially both inexpensive and scalable. The University of California-Davis team brings expertise in OPV device fabrication, optical modeling, and conjugated polymer synthesis to the project. The project is structured into three aims. Aim 1: Create NIR light‐trapping structures using rapid optical processing. The working hypothesis is that deep light‐trapping structures will optimize waveguide modes below the excitonic band gap, leading to enhanced absorbance in the NIR range. Aim 2: Synthesize OPV materials with controlled solubility for optimized patterning. The pattern fidelity is maximized by high molecular weight and low dispersity polymers that are active donors for OPV applications. And Aim 3: Develop, test and model patterned OPV devices with record power conversion efficiency (PCE). The team will use large‐area solution patterning to fabricate patterned OPV devices with the most promising polymeric active materials. This fundamental research will enable a departure from flat OPV layers to focus on light capture in sub‐band gap states. The expected significance extends beyond the individual device efficiency as other researchers will be able to adopt the patterning method and industry will be able to expand its use to large area organic device applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

光伏（pv）将阳光直接转化为电能，而不会产生任何温室气体。大多数商业光伏是由硅制成的，加工成本高，运输重，易碎。这个基础研究项目有助于开发由有机材料制成的光伏设备，这些材料成本低，重量轻，机械灵活。所有光伏设备的一个问题是，无论从任何角度入射，阳光都必须被吸收，而不是从表面反射。这个问题已经在硅光伏设备中得到了解决，方法是将硅的前后表面以特定的图案进行粗糙处理，从而使光被硅吸收，而不是被反射回太空。本研究项目采用了类似的工艺，将有机PV层的背面磨粗，以增强对太阳光谱中近红外部分的光的吸收，其中近红外部分包含了很大比例的太阳能。通过这种表面粗化工艺，有机光伏器件的效率将得到提高，使其成为清洁能源生产的更好的商业选择。这种模式还将使有机光伏在高入射角下更有效地吸收光线，这与早晚的阳光相似。本科生和博士研究生将接受研究技能的培训，这些技能在太阳能、聚合物和半导体行业很有价值。招生和推广活动旨在加强代表性不足的少数民族参与研究科学。我们迫切需要设计光源&amp；#8208；捕获结构到有机光伏（OPV）器件中，可以大大增加电荷&amp；#8208；转移态（CT）在近红外（NIR）中的吸光度。这个项目的目标是增强使用横向光的OPV器件的状态吸光度&amp；#8208；捕获结构。总体目标是开发一个滚动&amp；#8208；卷（R2R）兼容光学图案化工艺，用于划线横向光&amp；#8208；将结构捕获到OPV层中，可以提高CT&amp；#8208的外部量子效率（EQE）；在较宽的波长范围内吸光度高于20%的状态。这个项目的中心假设是：在ct8208状态下，OPV层的1000 nm二维横向图案与厚有源层相结合将实现20% EQE的目标。这项研究的基本原理是模拟光。捕集结构用于无机薄板；使用溶液处理方法的薄膜光伏装置，使OPV既便宜又可扩展。加州大学戴维斯分校的团队为该项目带来了OPV设备制造、光学建模和共轭聚合物合成方面的专业知识。该项目分为三个目标。目标1：创造近红外光；利用快速光学处理的捕获结构。工作假设是深光捕获结构将优化激子带隙以下的波导模式，从而增强近红外范围内的吸光度。目的2：合成可控制溶解度的OPV材料，用于优化图案化。高分子量和低分散性聚合物是OPV应用的活性供体，可以最大限度地提高图案保真度。目标3：开发，测试和建模具有创纪录功率转换效率（PCE）的图案化OPV器件。团队将使用大号&amp；#8208；区域溶液图案化，以制造图案化的OPV器件最有前途的聚合物活性材料。这项基础研究将使平面OPV层脱离，专注于子器件的光捕获。带隙态。预期的意义超出了单个器件的效率，因为其他研究人员将能够采用图案方法，工业将能够将其应用扩展到大面积有机器件应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。