Yang Chenchen, Zhang Jun, Peng Wei-Tao, Sheng Wei, Liu Dianyi, Kuttipillai Padmanaban S, Young Margaret, Donahue Matthew R, Levine Benjamin G, Borhan Babak, Lunt Richard R
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, 48824, USA.
Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
Sci Rep. 2018 Nov 5;8(1):16359. doi: 10.1038/s41598-018-34442-3.
Visibly transparent luminescent solar concentrators (TLSC) have the potential to turn existing infrastructures into net-zero-energy buildings. However, the reabsorption loss currently limits the device performance and scalability. This loss is typically defined by the Stokes shift between the absorption and emission spectra of luminophores. In this work, the Stokes shifts (SS) of near-infrared selective-harvesting cyanines are altered by substitution of the central methine carbon with dialkylamines. We demonstrate varying SS with values over 80 nm and ideal infrared-visible absorption cutoffs. The corresponding TLSC with such modification shows a power conversion efficiency (PCE) of 0.4% for a >25 cm device area with excellent visible transparency >80% and up to 0.6% PCE over smaller areas. However, experiments and simulations show that it is not the Stokes shift that is critical, but the total degree of overlap that depends on the shape of the absorption tails. We show with a series of SS-modulated cyanine dyes that the SS is not necessarily correlated to improvements in performance or scalability. Accordingly, we define a new parameter, the overlap integral, to sensitively correlate reabsorption losses in any LSC. In deriving this parameter, new approaches to improve the scalability and performance are discussed to fully optimize TLSC designs to enhance commercialization efforts.
可见透明发光太阳能聚光器（TLSC）有潜力将现有基础设施转变为净零能耗建筑。然而，目前重吸收损耗限制了该器件的性能和可扩展性。这种损耗通常由发光体吸收光谱和发射光谱之间的斯托克斯位移定义。在这项工作中，通过用二烷基胺取代中心次甲基碳来改变近红外选择性捕获花青的斯托克斯位移（SS）。我们展示了超过80nm的不同SS值以及理想的红外 - 可见光吸收截止值。具有这种改性的相应TLSC在大于25cm²的器件面积上显示出0.4%的功率转换效率（PCE），具有大于80%的优异可见光透明度，在较小面积上PCE高达0.6%。然而，实验和模拟表明，关键的不是斯托克斯位移，而是取决于吸收尾部形状的总重叠程度。我们用一系列SS调制的花青染料表明，SS不一定与性能或可扩展性的提高相关。因此，我们定义了一个新参数，重叠积分，以灵敏地关联任何LSC中的重吸收损耗。在推导该参数时，讨论了提高可扩展性和性能的新方法，以全面优化TLSC设计，加强商业化努力。
