新型热释电基宽光谱、高效率光热转换薄膜结构的设计、制备及性能研究

As one of the important applications of solar energy, the multilayer-based solar selective absorbers can be used to achieve high efficiency of solar-to-heat conversion. The thermal energy can be further converted into electricity using either the thermoelectric or pyroelectric effect. In the general condition, the relatively low optical absorption of the pyroelectric materials has put restriction for their broad application in the solar cell and photo-electronic fields. In this work, in terms of studying the optical properties of metal, dielectric and pyroelectric materials, combined with the optimal film structure design, the high efficiency of solar-to-heat absorption will be achieved in the broad 250-1700nm wavelength range, even extended further to the infrared region of > 1700nm. To realize direct solar-to-electricity conversion, several new methods will be carried out through the study, in which the layered structures with both high efficiency of solar-to-heat conversion and heat-to-electricity conversion will be effectively integrated together. The new devices have the merits of smaller size, easy for integration, simpler structure, higher stability and so on to be applied with good photo-electronic detection properties in the broad spectral region. The results with great innovation and feasibility of application in this work will stimulate the study and development of new types of solar cell and photo-electronics devices in the future.

光热转换是太阳能利用的重要方式之一，通过合理设计和制备高效率的太阳光吸收薄膜结构，可将入射的太阳光直接转换为热并加以充分利用。基于热释电效应，能够将热转换为电，但一般条件下热释电材料对太阳光的吸收率较低。限制了其在太阳能电池等领域的应用。在本项目中，通过研究金属、介质、热释电等材料的光学性质，结合光热转换薄膜结构的优化设计，能够在250-1700nm波段，甚至可扩展至更远的>1700nm的红外波长区实现太阳光的高效率吸收。在研究中，将采用金属/介质型高效率太阳光吸收薄膜与热释电薄膜材料相结合的方法，设计和研制可将高效率光热和热释电材料在结构上集成，进而实现直接光电转换的新型功能薄膜结构，具有体积小、易于集成化、结构简单、稳定性好等优点，预期能够在很宽的光谱区，实现室温红外探测等特性。研究成果不仅具有创新性，而且具有实际应用价值，将显著促进新型太阳能电池和宽光谱光电探测器件的研究和发展。

太阳光选择性吸收薄膜是太阳能光热转换系统的核心部件，其必须在最大程度上吸收太阳光的同时，尽量减少红外辐射造成的热量损失。本项目聚焦于太阳能光热转换这一新能源领域，开发了具有自主知识产权的多层膜型太阳光谱选择性吸收薄膜的设计程序，基于此，制备出多种太阳光吸收率高于95.5%，热辐射率低于0.05（100℃），并在500℃条件下长期稳定工作的太阳光谱选择性吸收薄膜。此外，开发了塞贝克系数自动化测量系统，为进一步研究太阳能光-热-电转换系统奠定了测量系统基础。初步制备了薄膜型光-热-电转换器件，探索了其在光照射下的电压和电流输出特性。本项目工作将可广泛应用于太阳能热水器、太阳能烘干、太阳能海水淡化和太阳能热电站等太阳能光热转换领域，尤其是太阳能热电站，具有极大的应用前景。