Gao Sheng, Balan Bamisha, Yoosaf Karuvath, Monti Filippo, Bandini Elisa, Barbieri Andrea, Armaroli Nicola
Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), Via Gobetti 101, 40129, Bologna, Italy.
Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, 695019, Kerala, India.
Chemistry. 2020 Aug 26;26(48):11013-11023. doi: 10.1002/chem.202001210. Epub 2020 Jun 3.
Five extended π-conjugated systems with electron donor (D) and acceptor (A) moieties have been synthesized. Their basic D-A-D structural motif is a benzothiadiazole unit symmetrically equipped with two thiophene rings (S2T). Its variants include 1) the same molecular framework in which sulfur is replaced by selenium (Se2T), also with four thiophene units (Se4T) and 2) a D'-D-A-D system having a N-carbazole donor moiety at one end (CS2T) and a D'-D-A-D-A' array with a further acceptor carbonyl unit at the other extremity (CS2TCHO). The goal is taking advantage of the intense luminescence and large Stokes shifts of the five molecules for use in luminescent solar concentrators (LSCs). All of them exhibit intense absorption spectra in the UV/Vis region down to 630 nm, which are fully rationalized by DFT. Emission properties have been studied in CH Cl (298 and 77 K) as well as in PMMA and PDMS matrices, measuring photoluminescence quantum yields (up to 98 %) and other key optical parameters. The dye-PMMA systems show performances comparable to the present state-of-the-art, in terms of optical and external quantum efficiencies (OQE=47.6 % and EQE=31.3 %, respectively) and flux gain (F=10.3), with geometric gain close to 90. LSC devices have been fabricated and tested in which the five emitters are embedded in PDMS and their wave-guided VIS luminescence feeds crystalline silicon solar cells.
已合成了五个带有电子供体（D）和受体（A）部分的扩展π共轭体系。它们基本的D - A - D结构基序是一个苯并噻二唑单元，对称地连接着两个噻吩环（S2T）。其变体包括：1）相同的分子框架，其中硫被硒取代（Se2T），也有四个噻吩单元（Se4T）；2）一个D'-D - A - D体系，一端有一个N - 咔唑供体部分（CS2T），以及一个在另一端带有另一个受体羰基单元的D'-D - A - D - A'阵列（CS2TCHO）。目标是利用这五个分子强烈的发光和大的斯托克斯位移，将其用于发光太阳能聚光器（LSC）。所有这些分子在紫外/可见区域直至630 nm都表现出强烈的吸收光谱，这通过密度泛函理论（DFT）得到了充分的合理解释。已在CHCl（298和77 K）以及聚甲基丙烯酸甲酯（PMMA）和聚二甲基硅氧烷（PDMS）基质中研究了发射特性，测量了光致发光量子产率（高达98%）和其他关键光学参数。染料 - PMMA体系在光学和外量子效率（分别为OQE = 47.6%和EQE = 31.3%）以及通量增益（F = 10.3）方面表现出与当前最先进水平相当的性能，几何增益接近90。已制造并测试了LSC器件，其中这五个发射体嵌入在PDMS中，它们的波导可见发光为晶体硅太阳能电池提供能量。
