Browsing by Author "Su, Yi-Jia"

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A chlorinated nonacyclic carbazole-based acceptor affords over 15% efficiency in organic solar cells
(2020-01-21)
Chen, Tsung-Wei
;
Peng, Kuan-Lin
;
Lin, You-Wei
;
Su, Yi-Jia
;
Ma, Ko-Jui
In this contribution, a dithienocyclopentacarbazole (DTC)-based and two dithieno[3,2-b]thiophenecyclopentacarbazole (DTTC)-based non-fullerene acceptors (NFAs) named DTC-4F, DTTC-4F and DTTC-4Cl were exploited to elucidate the effects of conjugation extension and end group chlorination. DTTC-4F was designed through conjugation extension on the basis of DTC-4F by fusing one additional thiophene on both flanks of the heptacyclic DTC core, generating the nonacyclic DTTC core. Compared with DTC-4F, DTTC-4F features up-shifted energy levels, red-shifted absorption and enhanced pi-pi interaction. PM6:DTTC-4F exhibits a decent PCE of 13.89% with a V-OC of 0.95 V, a J(SC) of 21.66 mA cm(-2) and a FF of 67.60%. Although DTTC-4F affords a reduced FF compared to DTC-4F, a DTTC-4F-based device delivers a higher PCE than DTC-4F-based devices due to the extended absorption range of DTCC-4F in comparison with DTC-4F. Since chlorinated NFAs are known to possess stronger pi-pi interaction than fluorinated NFAs, DTTC-4Cl was therefore synthesized by end-capping DTTC core with 2Cl-IC groups instead of 2F-IC groups. Moreover, DTTC-4Cl demonstrates a red-shifted absorption in comparison with DTTC-4F, which is beneficial for light-harvesting. Overall, PM6:DTTC-4Cl affords an outstanding PCE of 15.42% with a V-OC of 0.92 V, a J(SC) of 22.64 mA cm(-2) and a FF of 74.04%, which is the record PCE observed in carbazole-based NFAs.
Chlorinated Carbon-Bridged and Silicon-Bridged Carbazole-Based Nonfullerene Acceptors Manifest Synergistic Enhancement in Ternary Organic Solar Cell with Efficiency over 15%
(1970-01-01)
Chen, Tsung-Wei
;
Yu, Jun-Yan
;
Lin, You-Wei
;
Peng, Shih-Hao
;
Wu, Shang-Hsuan
Herein, two novel nonfullerene acceptors (NFAs), DTCC-4Cl and DTSiC-4Cl, are synthesized by end-capping dithienocyclopentacarbazole (DTCC) and dithieno-silolocarbazole (DTSiC) cores with chlorinated IC (2Cl-IC) units, respectively. With the better-known advantage of having the extraordinary sigma*-pi* conjugation of silole unit embedded in the DTSiC core, DTSiC-4Cl manifests upshifted lowest unoccupied molecular orbital (LUMO), blue-shifted absorption, and increased pi-pi interaction in comparison with DTCC-4Cl. Furthermore, to elucidate the effect of bridging atoms on the photovoltaic performance, T1 is selected as the polymer donor to be blended with DTCC-4Cl and DTSiC-4Cl. T1:DTCC-4Cl-based devices exhibit a fine power conversion efficiency (PCE) of 14.43% and T1:DTSiC-4Cl-based devices exhibit a comparable PCE of 14.46%. Interestingly, the T1:DTSiC-4Cl-based devices demonstrate an additive-free feature, which is worthy of further applications. From the perspective of constructing high-performance ternary devices, DTCC-4Cl is expected to possess excellent compatibility with DTSiC-4Cl owing to its structural similarity. As anticipated, the ternary T1:DTSiC-4Cl:DTCC-4Cl-based device outperforms the binary T1:DTCC-4Cl and T1:DTSiC-4Cl-based devices, affording a decent PCE of 15.04% with aV(OC)of 0.97 V, aJ(SC) of 20.80 mA cm(-2), and an FF of 74.55% without any additive.
Porphyrin-Containing Polymer as a Superior Blue Light-Absorbing Additive To Afford High-J(sc) Ternary Solar Cells
(2019-01-09)
Li, Chia-Hua
;
Chang, Chia-Chih
;
Hsiao, Yu-Hsuan
;
Peng, Shih-Hao
;
Su, Yi-Jia
Integrating an additional component featuring complementary light absorption into binary polymer solar cells is a superior tactic to ameliorate solar cell efficiency and stability. An appropriate additive not only extends the absorption range but may also facilitate charge separation and transport processes. In this work, we elucidate the effects of incorporating a porphyrin-containing conjugated polymer (PPor-1), which displays absorption in 350-500 nm, into binary PTB7-Th:4TIC and PTB7-Th:ITIC blends, affording devices with an average power conversion efficiency approaching 9%. We successfully demonstrate that PPor-1 can be incorporated as an additive to impart improved J(sc) (up to 19.1 mA cm(-2)).