高效光吸收宽谱广角仿生光功能材料制备及其光能转换研究

It is particularly important to enhance the overall efficiency of solar energy utilization by design and preparation of highly efficient solar absorber functional materials worked on wider waveband and larger incident angle. Two limited methods used currently, that is component adjustment and surface texture, are not very benefit on the light absorbance enhancement and easily proceeding. Some special nature species, such as butterflies, snakes and leaves, for the purpose to survive, have evoluted the light absorption exocuticles with high light-trapping ability due to the subtle three-dimensional microstructure. The difficulty to fabricate such fine microstructures in lab has greatly inhibited the research on design and fabrication these subtle structures with higher light absorbance efficiency worked on wide waveband and larger incident angle. To solve this critical problem, this project will use these natural species as the direct or indirect biological template. By the chemical and physical fabrication method, intensive researches on the fabrication process of more efficient light-absorbing structure will be conducted. More efforts will be focused on the phase and microstructures conversion, the intrinsic relationship between the microstructures and waveband and incident angles. Moreover, a mathematic model based on Finite Difference Time Domain (FDTD) and multi-physical fields will be established to simulate the light absorbance and energy conversion process. The coupling effects between microstructures and related optical functions will be revealled then. All of the above studies will provide a theoretical basis and practical ways to the future development on optical functional materials with high efficiency light absorbance and light conversion.

设计和制备出在更宽光谱波段和更大入射角条件下的高效光吸收功能材料，对于太阳光能利用整体效率提高尤其重要。目前多采用组分复合和表面简单粗糙化这两种方案，导致光吸收能力提升有限且无法实现简捷制备。而自然界的某些特殊物种，如蝴蝶、蛇等，为了能在寒冷条件下生存，进化出具有极高光吸收能力的三维微纳结构外表皮。而目前实验室尚无法制备与此类似的精细结构，这极大抑制了针对利用这一精细结构提高在宽谱广角条件下高效吸收太阳光的研究。为解决这一关键问题，本研究主要利用上述生物材料作为生物模板，结合化学物理耦合和纳米压印方法，制备出具有仿生结构的高效光吸收宽谱广角光吸收及光能转换材料，并研究制备过程中相及组织的演化规律，微纳结构与宽谱广角光吸收性能及光能转换的内在关系。构建物理模型拟实揭示微纳结构与光功能特性间的耦合响应机制，为今后设计制备在宽谱广角下具有高效光吸收特性的光功能材料提供理论依据和实用途径。

设计和制备出在更宽光谱波段和更大入射角条件下的高效光吸收功能材料，对于太阳光能利用整体效率提高尤其重要。本研究在基金委的支持下，启迪于自然中具有极高光吸收能力的三维微纳结构的生物微纳光学构型，主要就光吸收功能材料的宽谱减反构型设计、光能吸收和转换一体化材料的构型甄选和制备开展研究。结合化学物理复合制备方法，制备出具有仿生构型的高效光吸收宽谱广角光吸收及光能转换材料，同时利用有限时域差分法研究了制备过程中相及组织的演化规律，微纳结构与宽谱广角光吸收性能及光能转换的内在关系。构建物理模型拟实揭示微纳结构与光功能特性间的耦合响应机制。在可见-近红外区域平均光吸收加强可较商用Bluetec膜增益102.63%，在中红外区域可加强54.9倍；红外光热转换效率可达30.56%，低发射比下的太阳光吸收比可达98%，低温工作区域内太阳能光热转化性能优异。而且在大入射角照射下，实现了可见光谱下仅 7.8%的反射率。有利于在光伏、光热等太阳能应用领域的全天候应用，获得包括 ScienceDaily， Nanowerk 等国内外 30 余家科技媒体的报道；针对复杂三维微纳光能增益构型，开展了针对双连续联通结构的前期研究，相关研究发表在Nature子刊《自然亚洲材料NPG Asia Materials》上；成功制备了具有 4.3kg/m2h光热蒸发率的光热蒸发膜与相关组件，该体系充分利用了宽波段光吸收的散射截面大、等离激元协同增强效应。上述研究为今后设计制备在宽谱广角下具有高效光吸收特性的光功能材料提供理论依据和实用途径，可为未来光热、光伏、光催化和光传感等领域的应用提供解决方案。