- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Novel swivel-cruciform 5,5′-bibenzothiadiazole based small molecule donors for efficient organic solar cells
摘要： 5,5′-bibenzothiadiazole (BBT), which is a dimer of widely used electron deficient building block benzothiadiazole (BT), offers great promise for developing highly efficient electron donors because of its unique structural features. However, a small quantity of work has been reported on BBT based donors, and their overall performances are still far behind those of their BT counterparts. In order to make a contribution in this regard, the novel small molecules were synthesized and applied as donor materials in the bulk heterojunction solar cells, in which the BBT was used as the central node. Compared with the corresponding linear BT based molecule, the swivel-cruciform BBT based molecule exhibited significantly enhanced photovoltaic performance with an impressive power conversion efficiency of 7.21%, which is the best reported device performance based on BBT-core materials in organic solar cells. These results indicate the great potential of BBT for high performance solar cells.
关键词： Swivel-cruciform structure,Organic solar cells,5,5′-bibenzothiadiazole unit,Small molecule donors
更新于2025-09-19 17:13:59
-
Di‐fluorinated Oligothiophenes for High‐Efficiency All‐Small‐Molecule Organic Solar Cells: Positional Isomeric Effect of Fluorine Substitution on Performance Variations
摘要： Three symmetrically di-fluorinated organic semiconductors (namely D5T2F-P, D5T2F-S, and D5T2F-T) containing rhodanine-flanked pentathiophene structures are synthesized and used as donors in all-small-molecule organic solar cells (ASM-OSCs) prepared with the small-molecule acceptor 2,2'-((2Z,2'Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC-4F). The different substitutional positions of the fluorine atoms (-F) in the conjugated backbone of the donor molecule leads to various material and photovoltaic properties being exhibited. Among the three isomers, the centrally-fluorinated D5T2F-P exhibits a redshifted absorption spectrum, downshifted highest occupied molecular orbital (HOMO) energy level, and improved miscibility with IDIC-4F in the blend films, all of which result in superior device performance. The power conversion efficiency (PCE) of the ASM-OSCs based on D5T2F-P:IDIC-4F reaches the impressive value of 9.36% with an open-circuit voltage (VOC) value of 0.86 V and a short-circuit current density (JSC) value of 16.94 mA/cm2, while those of D5T2F-S (6.11%) and D5T2F-T (5.42%) are much lower. In comparison, an ASM-OSC based on the non-fluorinated analogue DRCN5T fabricated under the same conditions exhibits poorer performance (8.03% with IDIC-4F), revealing a 16% enhancement in PCE achieved through backbone fluorination. To the best of our knowledge, the PCE of 9.36% is one of the highest efficiencies of oligothiophene-based ASM-OSCs reported in the literature to date.
关键词： organic solar cells,binding energy,small molecule donors,fluorination,non-fullerene
更新于2025-09-12 10:27:22
-
Markedly different molecular formation in DPP-based small-molecule solar cells probed by grazing-incidence wide-angle X-ray scattering
摘要： This study comprehensively explores the nanostructural properties of two diketopyrrolo[3,4-c]pyrrole-1,4-dione (DPP)-based small molecules with different alkyl side groups and their blends with the fullerene derivative PC71BM, using grazing-incidence wide-angle X-ray scattering synchrotron techniques. Preferentially relative face-on orientation within the larger and more ordered stacking phase of SM1 with its shorter side group (ethylhexyl) was observed in the majority of both pristine and blend thin films, whereas SM2 crystals showed strictly perpendicular orientation. These contrasting crystalline characteristics led to significant differences in the results, from which crystalline structure–performance property correlations are proposed. Thus, the results not only demonstrate important scientific insights into the relationship between molecular structure and crystalline formation but also provide molecular design directions that will facilitate further improvement to the morphology and performance of DPP-based small-molecule solar cells.
关键词： small-molecule donors,diketopyrrolopyrrole,grazing-incidence wide-angle X-ray scattering,molecular packing structure,small-molecule solar cells
更新于2025-09-11 14:15:04