Effects of the Center Units of Small‐molecule Donors on the Morphology, Photovoltaic Performance and Device Stability of All‐small‐molecule Organic Solar Cells

Solar RRL ◽  
2021 ◽  
Author(s):  
Shaman Li ◽  
Qing Ma ◽  
Beibei Qiu ◽  
Lei Meng ◽  
Jinyuan Zhang ◽  
...  
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.


2015 ◽  
Vol 51 (28) ◽  
pp. 6133-6136 ◽  
Author(s):  
Yao Chen ◽  
Youqin Zhu ◽  
Daobin Yang ◽  
Qian Luo ◽  
Lin Yang ◽  
...  

Asymmetrical squaraine dyes with two aryl groups directly linked to the squaric acid core were synthesized, and exhibited excellent photovoltaic performance.


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.


2018 ◽  
Vol 6 (45) ◽  
pp. 12347-12354 ◽  
Author(s):  
Hongyan Huang ◽  
Bo Xiao ◽  
Chengting Huang ◽  
Jing Zhang ◽  
Shuli Liu ◽  
...  

The effects of the geometric shape of l-IDT and a-IDT subunits on the thermal, optical, electrochemical and film-forming properties, the charge mobility and the photovoltaic performance of the resulting acceptors were investigated.


2019 ◽  
Vol 01 (01) ◽  
pp. 071-077
Author(s):  
Di Zhou ◽  
Zhilin Liu ◽  
Dangqiang Zhu ◽  
Xiyue Yuan ◽  
Xichang Bao ◽  
...  

How to broaden the optical absorption of photovoltaic materials is one of the key issues in the design of high-performance organic solar cells. Nowadays, the sunlight of 400–550 nm wavelength range is not effectively utilized for most small-molecule nonfullerene acceptors. In this work, we proposed the “spliced” strategy of combining the acceptor–donor–acceptor type narrow band-gap small molecules and wide-band-gap perylene diimide (PDI) moieties via a flexible alkyl chain linkage, which could give the superposition effect of the absorption spectra, and three small-molecule acceptors (S1, S2, and S3) were designed based on various end-capping groups with different electron withdrawing abilities. Encouragingly, the as-constructed molecules can well make use of 400–550 nm sunlight with two independent absorption regions. Meanwhile, the aggregation of S1 with a highly planar end-capping group was dominated by both the PDI unit and main skeleton, while S2 and S3 exhibited PDI-controlled aggregation. When fabricated into organic solar cells, S1-based devices achieved a superior efficiency of 3.41% in comparison with those of the other two. The poor photovoltaic performance could be attributed to severe PDI aggregation, which can hinder the charge transfer through the main skeletons. This work could provide a new perspective to modulate optical absorption through the spliced strategy.


2019 ◽  
Vol 7 (18) ◽  
pp. 5381-5384 ◽  
Author(s):  
Qian Zhang ◽  
Yanna Sun ◽  
Xianjie Chen ◽  
Zhijing Lin ◽  
Xin Ke ◽  
...  

A new A2–π–A1–π–A2-type small-molecule donor using a strong electron-withdrawing unit as the central unit was synthesized and its photovoltaic performance was investigated.


2016 ◽  
Vol 4 (22) ◽  
pp. 8784-8792 ◽  
Author(s):  
Ting Wang ◽  
Liangliang Han ◽  
Huan Wei ◽  
Dangqiang Zhu ◽  
Xichang Bao ◽  
...  

A new small moleculeDCATT-Lwith the same building blocks but a different π-bridge configuration compared to that ofDCATTexhibited higher photovoltaic performance.


2019 ◽  
Vol 01 (01) ◽  
pp. 088-094 ◽  
Author(s):  
Junhui Miao ◽  
Bin Meng ◽  
Jun Liu ◽  
Lixiang Wang

Small-molecule donor/polymer acceptor type (MD/PA-type) organic solar cells (OSCs) have the great advantage of superior thermal stability. However, very few small molecular donors can match polymer acceptors, leading to low power conversion efficiency (PCE) of MD/PA-type OSCs. In this work, we studied the effect of terminal groups of small molecular donors on the optoelectronic properties and OSC device performance of MD/PA-type OSCs. We select a benzodithiophene unit bearing carbazolyl substituents as the core, terthiophene as the bridging unit, and electron-withdrawing methyl 2-cyanoacetate, 3-ethylrhodanine, and 2H-indene-1,3-dione as the terminal groups to develop three small-molecule donors. With the increase of the electron-withdrawing capability of the terminal groups, the small molecular donors exhibit redshifted absorption spectra and downshifted LUMO levels. Among the three small-molecule donors, the one with 3-ethylrhodanine terminal group exhibits the best photovoltaic performance with the PCE of 8.0% in MD/PA-type OSCs. This work provides important guidelines for the design of small-molecule donors for MD/PA-type OSC applications.


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