Light management by disordered nano-structures for optoelectronic devices (LAMBDA)

本课题属于二维平面无序纳米结构光电薄膜器件的光管理领域。后者被设计成一种高效的散射结构，其主要目标是改善白色有机发光二极管（WOLEDs）的解耦特性，从而提高其功率效率。这里开发的方法和结构也将对光伏领域产生直接影响。因此，计划测试工程结构以改善非晶硅薄膜太阳能电池的光捕获能力，非晶硅薄膜太阳能电池具有与WOLEDs相当的光谱范围。作为任何实验研究的先决条件，使用基于横向相分离的多功能、大面积、湿化学技术，将建立一个成熟的制造路线，以创建具有可控无序特性的光子结构。为了优化所产生的结构，将开发一种新的光学建模方法，使其能够在低计算资源需求的情况下，通过嵌入在薄膜系统中的大量圆柱形散射中心集合来严格计算散射。它还将与先进的扫描近场光学显微镜技术结合使用，以进一步了解起作用的物理机制。从这些分析中获得的信息将有助于将散射层集成到两个目标器件中，并将测量其在效率提高方面的影响。在这个跨学科的实验/理论研究范围内，解决了与薄膜系统内平面伪无序结构的光散射有关的具体问题，并包括这些层对相干多散射现象，激子寿命或表面等离子激元极化子提取的影响。

The present proposal falls into the field of light management for optoelectronic thin film devices using 2D planar disordered nano-structures. The latter are designed to act as an efficient scattering architecture whose main goal is to improve the outcoupling properties of white organic light emitting diodes (WOLEDs), and consequently to increase their power efficiency. The methodology and structures developed here will also have direct implications for the field of photovoltaics. Thus, it is planned to test the engineered structures to ameliorate the light-trapping capabilities of amorphous silicon thin-film solar cells, which possess a comparable spectral range of operation as WOLEDs.As a prerequisite for any experimental investigations, a mature fabrication route for the creation of photonic structures with controllable disorder properties will be established using a versatile, large area, wet-chemical technique based on lateral phase separation. In order to optimize the structures produced, a novel optical modeling method will be developed enabling the rigorous calculation of the scattering by a large ensemble of cylindrical scattering centers embedded in a thin film system with low computational resources demands. It will also be used in combination with advanced techniques of scanning near-field optical microscopy to provide further insights into the physical mechanisms at play. The information derived from those analyses will facilitate the integration of the scattering layers into the two targeted devices, and their impact in terms of efficiency increase will be measured.Within the scope of this interdisciplinary experimental/ theoretical study, specific questions related to light scattering by planar pseudo-disordered structures inside thin films systems are addressed, and encompass the influence of those layers on coherent multi-scattering phenomena, on the excitons life time or on the extraction of surface plasmon polaritons.