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Enhanced Efficiency and Stability of Nonfullerene Ternary Polymer Solar Cells Based on Spontaneously Assembled Active Layer: The Role of a High Mobility Small Molecular Electron Acceptor
摘要： It is challenging to afford efficient and stable organic solar cells based on the as-cast active layer without any external treatments. We present a planar organic electron acceptor BPTCN with high electron mobility as a third component in nonfullerene ternary polymer solar cells, which comprises an electron-deficient 4,7-bis(5H-4,6-dioxothieno[3,4-c]pyrrol-1-yl)benzo[c][1,2,5]thiadiazole core, doubly endcapped by 2-(3-ethyl-5-methylene-4-oxothiazolidin-2-ylidene)malononitrile through the alkylated thiophene-2,5-ylene unit. It shows a π-π stacking distance of 3.60 ? and μe of 1.31 × 10?3 cm2 V?1 s?1. BPTCN exhibits an absorption maximum at 569 nm in the as-cast film and good miscibility with the NIR-absorption acceptor COi8DFIC, leading to complete f?rster energy transfer in the blends. Adding BPTCN into the PTB7-Th:COi8DFIC blend produces multiple beneficial effects: i) facilitating exciton dissociation and charge transfer at the donor/acceptor interface while suppressing bimolecular and trap-assisted recombination by analysis of the Jph–Veff, Jsc–Ilight and Voc–Ilight characteristics, ii) increasing hole and in particular electron transport; and iii) generally promoting the crystallinity of the polymer donor PTB7-Th, as revealed by grazing incidence X-ray diffraction. Moreover, the phase purity is greatly improved in the ternary blend PTB7-Th:COi8DFIC:BPTCN (1:1.05:0.45 by weight). Consequently, the tentatively optimized ternary solar cell provides a PCE of 11.62% with Voc = 0.74 V, Jsc = 25.93 mA cm-2 and FF = 60.61% in comparison with the binary systems PTB7-Th:COi8DFIC (PCE of 9.41%) and PTB7-Th:BPTCN (6.42%) in the absence of any extra treatments. After thermal aging at 80 oC for 450 h, this ternary solar cell exhibits increased stability with PCE retaining 84.39% of the initial value.
关键词： PTB7-Th,COi8DFIC,BPTCN,electron acceptor,organic solar cells,thermal stability,nonfullerene ternary polymer solar cells
更新于2025-09-23 15:19:57
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Highly efficient ternary polymer solar cell with two non-fullerene acceptors
摘要： Polymer solar cells (PSCs) based on binary and ternary active layers were built using PBDB-T polymer as donor and two non-fullerene acceptors (MPU2 and MPU3) with different DPP cores and terminal units but different conjugation length. The studied binary PSCs showed PCE (power conversion efficiency) values of 8.22% (PBDB-T:MPU2) and 9.77% (PBDB-T:MPU3). The VOC measured using the MPU3-based acceptor was higher than that obtained using MPU2 – this difference is attributed to a higher LUMO energy level of MPU3. MPU2 and MPU3 present complementary absorptions in the wavelength range where PBDB-T exhibits a poor absorption, thus the combination of these materials offers great potential for the fabrication of ternary PSCs. The solar cell with an optimized ternary layer PBDB-T:MPU2:MPU3 (1:1:1) showed an PCE value of 10.78%, higher than those obtained for the binary devices due to the enhanced of JSC and FF values. And, since the emission of MPU3 partially overlaps with the absorption of MPU2, the transfer of energy from MPU3 to MPU2 can improve the exciton utilization efficiency and achieve enhanced overall power conversion efficiency in this ternary solar cell.
关键词： Polymer donor,Power conversion efficiency,Non-fullerene acceptor,Ternary polymer solar cells
更新于2025-09-23 15:19:57
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Ternary Polymer Solar Cells Facilitating Improved Efficiency and Stability
摘要： The use of a ternary active layer offers a promising approach to enhance the power conversion efficiency (PCE) of polymer solar cells (PSCs) via simply incorporating a third component. Here, a ternary PSC with improved efficiency and stability facilitated by a new small molecule IBC-F is demonstrated. Even though the PBDB-T:IBC-F-based device gives an extremely low PCE of only 0.21%, a remarkable PCE of 15.06% can be realized in the ternary device based on PBDB-T:IE4F-S:IBC-F with 20% IBC-F, which is ≈10% greater than that (PCE = 13.70%) of the control binary device based on PBDB-T:IE4F-S. The improvement in the device performance of the ternary PSC is mainly attributed to the enhancement of fill factor, which is due to the improved charge dissociation and extraction, suppressed bimolecular and trap-assisted recombination, longer charge-carrier lifetime, and enhanced intermolecular interactions for preferential face-on orientation. Additionally, the ternary device with 20% IBC-F shows better thermal and photoinduced stability over the control binary device. This work provides a new angle to develop the third components for building ternary PSCs with enhanced photovoltaic performance and stability for practical applications.
关键词： power conversion efficiency,stability,fill factor,ternary polymer solar cells
更新于2025-09-12 10:27:22