scholarly journals An investigation of the role acceptor side chains play in the processibility and efficiency of organic solar cells fabricated from small molecular donors featuring 3,4-ethylenedioxythiophene cores

RSC Advances ◽  
2018 ◽  
Vol 8 (69) ◽  
pp. 39231-39240
Author(s):  
N. A. Mica ◽  
S. A. J. Almahmoud ◽  
L. Krishnan Jagadamma ◽  
G. Cooke ◽  
I. D. W. Samuel

The chemical nature of the acceptor side chain plays an important role in the processability and photovoltaic performance of EDOT-based small molecule donors.

2020 ◽  
Vol 02 (01) ◽  
pp. 026-032
Author(s):  
Chen Yang ◽  
Liu Yuan ◽  
Ruimin Zhou ◽  
Zhen Wang ◽  
Jianqi Zhang ◽  
...  

The molecular stacking assembly in the active layer plays a significant role in the photovoltaic performance of organic solar cells (OSCs). Here, we report two new small molecular donors with different side chains, FBT-O and FBT-H, and their corresponding fullerene-based OSCs. A slight change in the side chains led to a big difference in the power conversion efficiencies (PCEs). Although the molecular structures of the two donors are similar to each other, PCEs of the devices based on FBT-O were almost three times higher than those of the devices based on FBT-H, with manifold short-circuit current density, fill factor, as well as three orders of magnitude enhancement in the hole mobility. The difference in their single crystal structures was thoroughly investigated, whereby the FBT-O exhibited better planarity leading to appropriate phase separation and domain size. Furthermore, two-dimensional grazing-incidence wide-angle X-ray scattering results of the blend films revealed that the two donors retained a similar stacking structure as compared to the single-crystal structures, thus, establishing a clear relationship between the molecular stacking structure and the device performance.


2018 ◽  
Vol 6 (46) ◽  
pp. 23270-23277 ◽  
Author(s):  
Jing Liu ◽  
Lik-Kuen Ma ◽  
Zhengke Li ◽  
Huawei Hu ◽  
Fu Kit Sheong ◽  
...  

The synergistic effects of overfluorination and alkylthiophene side chain strategies led to 10.60% efficiency for non-fullerene organic solar cells.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1324 ◽  
Author(s):  
Weifang Zhang ◽  
Zicha Li ◽  
Suling Zhao ◽  
Zheng Xu ◽  
Bo Qiao ◽  
...  

At present, most high-performance non-fullerene materials are centered on fused rings. With the increase in the number of fused rings, production costs and production difficulties increase. Compared with other non-fullerenes, small molecule INTIC has the advantages of easy synthesis and strong and wide infrared absorption. According to our previous report, the maximum power conversion efficiency (PCE) of an organic solar cell using PTB7-Th:INTIC as the active layer was 7.27%. In this work, other polymers, PTB7, PBDB-T and PBDB-T-2F, as the donor materials, with INTIC as the acceptor, are selected to fabricate cells with the same structure to optimize their photovoltaic performance. The experimental results show that the optimal PCE of PBDB-T:INTIC based organic solar cells is 11.08%, which, thanks to the open voltage (VOC) increases from 0.80 V to 0.84 V, the short circuit current (JSC) increases from 15.32 mA/cm2 to 19.42 mA/cm2 and the fill factor (FF) increases from 60.08% to 67.89%, then a 52.4% improvement in PCE is the result, compared with the devices based on PTB7-Th:INTIC. This is because the PBDB-T:INTIC system has better carrier dissociation and extraction, carrier transportation and higher carrier mobility.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ruimin Zhou ◽  
Zhaoyan Jiang ◽  
Chen Yang ◽  
Jianwei Yu ◽  
Jirui Feng ◽  
...  

AbstractThe high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.


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