折射率对碳点基发光太阳能聚光器光电性能的影响

Effect of Refractive Index on Photoelectric Properties of Carbon Dots-based Luminescent Solar Concentrator

发光太阳能聚光器作为一种新型的实现低成本电力的潜在光伏技术已经引起了广泛的关注。选择合适的荧光基质和性能优异的光波导介质成为该技术得以推广应用的关键。目前,多数研究者把目光聚焦在荧光基质光学性能的提高上,对光波导介质性能的优化却鲜有报道。本文使用邻苯二甲酸和邻苯二胺两种前驱体,一步微波法快速高效地合成了一种晶态碳点。鉴于该碳点具有绿色荧光,荧光量子产率超过80%,并且吸收和发射光谱间存在较大的斯托克斯位移,适合作为新型太阳能聚光器用荧光基质。另外,采用预聚体法制备了高透明的聚氨酯膜,并作为发光太阳能聚光器用光波导介质研究了其光学性能。通过引入硫元素,该薄膜的折射率从1.483提高到1.547,这直接导致利用所制备的碳点作为荧光基质封装的聚氨酯薄膜型发光太阳能聚光器器件的光电转换效率提升了41%。该结果不仅证实了聚氨酯作为光波导介质的可行性,更为通过改良光波导介质的折射率来提高光传输的研究方法提供了实验依据。

Luminescent solar concentrator(LSC),as a new potential solar technology to achieve low cost electricity,has attracted wide attention,and it is the key to popularize the technique to select suitable fluorescent substrate and waveguide medium with excellent optical property.Up to now,most researchers focus on the improvement of optical properties of fluorescent substrates,but there are few reports on the performance optimization of optical waveguide medium.Here,a crystalline carbon dots(CDs)was synthesized by one-step microwave method using two precursors of phthalic acid and phthalenediamine.Since the CDs can emit green fluorescence and has a large Stokes shift between absorption and emission spectra,it is suitable as a fluorescent substrate for a new type of solar concentrator.In addition,highly transparent polyurethane(PU)films were prepared by prepolymer method,and their optical properties were studied as optical waveguide medium for LSC.By introducing sulfur element,the refractive indexes of these films were increased from 1.483 to 1.547,which directly led to a 41%increase in the photoelectric conversion efficiency of the PU film-based LSC device encapsulated with the prepared CDs as the fluorescent matrix.The results not only confirm the feasibility of PU as optical waveguide medium,but also provide experimental basis for the research method of improving optical transmission by increasing the refractive index of optical waveguide medium.