| 1. |
- Wu, Jingnan, 1994, et al.
(författare)
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New Electron Acceptor with End-Extended Conjugation for High-Performance Polymer Solar Cells
- 2021
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 35:23, s. 19061-19068
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Tidskriftsartikel (refereegranskat)abstract
- To develop high-efficiency polymer solar cells (PSCs), the acceptors in a bulk heterojunction (BHJ) blend are supposed to possess complementary absorption bands in the near-infrared region and a suitable energy level to be well-matched with the donors. In this work, a new small molecular acceptor (SMA) named IDTT8-N based on an indacenodithienothiophene (IDTT) core was designed and synthesized. In comparison to the counterpart molecule IDTN with an indacenodithiophene (IDT) core, IDTT8-N with the extended π-conjugation length of an IDT core not only exhibits a red shift of ca. 35 nm in optical absorption but also has little change on its lowest unoccupied molecular orbital (LUMO) energy level. Therefore, PSCs based on PM6:IDTT8-N exhibit a superior short-circuit current density (Jsc) and high open-circuit voltage (Voc). Moreover, apart from the strong face-on molecular stacking, distinct end-group π-πstacking of IDTT8-N can be observed in the blends, facilitating the charge transport. Therefore, the optimized PM6:IDTT8-N-based devices exhibit dramatically high and balanced electron mobility (μe) and hole mobility (μh), whose magnitudes are over 10-3 cm2 V-1 s-1. Consequently, an extraordinary PCE of 14.1% with a relatively high Jsc of 20.98 mA cm-2 and a Voc of 0.94 V was recorded. To our knowledge, it is the new record among PSCs with a SMA based on 2-(3-oxocyclopentylidene)malononitrile (INCN) as end groups. These results indicate that extending the π-conjugation length of the fused ring core of a SMA is an efficient method to both enhance the absorption and the molecular interaction of the acceptor as well as the photovoltaic performance of PSCs.
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| 2. |
- Yan, Xin, et al.
(författare)
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Highly efficient ternary solar cells with reduced non-radiative energy loss and enhanced stability via two compatible non-fullerene acceptors
- 2022
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 10:29, s. 15605-15613
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Tidskriftsartikel (refereegranskat)abstract
- A ternary strategy by introducing a third component into a binary host system has been proven to be a simple and promising method to boost the power conversion efficiency (PCE) and stability of organic solar cells (OSCs). Herein, a high efficient ternary OSC is fabricated, wherein, a non-fullerene acceptor, namely MOIT-M, is introduced as a third component into the PM6:BTP-eC9 blend. MOIT-M possesses good complementary absorption spectra and aligned cascade energy levels with the host binary blend, which benefits light harvesting, exciton dissociation, and charge transport. Moreover, MOIT-M exhibits good miscibility with BTP-eC9, forming a well-mixed phase, which improves molecular packing for better charge transport and optimizes ternary blend morphology. Notably, the incorporation of MOIT-M suppresses non-radiative recombination, leading to reduced non-radiative energy losses (Delta E-nr). As a result, the ternary OSC exhibits a significantly increased PCE of 18.5% with a lower Delta E-nr of 0.21 eV in comparison with the control binary PM6:BTP-eC9 device with a PCE of 17.4% and a Delta E-nr of 0.24 eV. In addition, the ternary OSC displays better storage stability compared to the PM6:BTP-eC9 system. This work indicates that a ternary strategy via combining two compatible small molecule acceptors is effective to simultaneously improve the efficiency and stability of OSCs.
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| 3. |
- Zhang, Zhiliang, et al.
(författare)
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Enhancing intermolecular packing and light harvesting through asymmetric non-fullerene acceptors for achieving 18.7% efficiency ternary organic solar cells
- 2023
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 11:28, s. 15553-15560
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the ternary strategy has been proven to be an effective way to improve the performance of organic solar cells (OSCs). Herein, an asymmetric medium-band gap non-fullerene acceptor (AFIC) is synthesized and added as the third component into the PM6:BTP-eC9 binary blend for a highly efficient ternary OSC. AFIC exhibits a well-complementary absorption spectrum with the host binary blend, which benefits light harvesting of the active layer. Furthermore, AFIC shows a large dipole moment and good miscibility with BTP-eC9, which facilitates the formation of a stable well-mixed phase and enhances molecular packing in the blend, leading to improved charge transport and suppressed charge recombination in ternary devices. As a result, the ternary OSC based on PM6:BTP-eC9:AFIC demonstrates a significantly improved power conversion efficiency (PCE) of 18.7% while the binary OSC based on PM6:BTP-eC9 shows a PCE of 17.5%, which is attributed to the synergistic enhancement of the open-circuit voltage (V-oc), short-circuit current density (J(sc)), and fill factor (FF).
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