Mulder C L, Reusswig P D, Velázquez A M, Kim H, Rotschild C, Baldo M A
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Opt Express. 2010 Apr 26;18 Suppl 1:A79-90. doi: 10.1364/OE.18.000A79.
Luminescent solar concentrators (LSCs) use dye molecules embedded in a flat-plate waveguide to absorb solar radiation. Ideally, the dyes re-emit the absorbed light into waveguide modes that are coupled to solar cells. But some photons are always lost, re-emitted through the face of the LSC and coupled out of the waveguide. In this work, we improve the fundamental efficiency limit of an LSC by controlling the orientation of dye molecules using a liquid crystalline host. First, we present a theoretical model for the waveguide trapping efficiency as a function of dipole orientation. Next, we demonstrate an increase in the trapping efficiency from 66% for LSCs with no dye alignment to 81% for a LSC with vertical dye alignment. Finally, we show that the enhanced trapping efficiency is preserved for geometric gains up to 30, and demonstrate that an external diffuser can alleviate weak absorption in LSCs with vertically-aligned dyes.
发光太阳能聚光器（LSCs）利用嵌入平板波导中的染料分子来吸收太阳辐射。理想情况下，染料将吸收的光重新发射到与太阳能电池耦合的波导模式中。但总会有一些光子损失，通过LSC的表面重新发射并耦合出波导。在这项工作中，我们通过使用液晶主体控制染料分子的取向来提高LSC的基本效率极限。首先，我们提出了一个波导俘获效率作为偶极子取向函数的理论模型。接下来，我们证明了俘获效率从无染料取向的LSCs的66%提高到垂直染料取向的LSC的81%。最后，我们表明，在几何增益高达30时，增强的俘获效率得以保持，并证明外部扩散器可以减轻垂直排列染料的LSCs中的弱吸收。
