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- Genene, Zewdneh, 1983, et al.
(author)
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A comparative study of the photovoltaic performances of terpolymers and ternary systems
- 2017
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:29, s. 17959-17967
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Journal article (peer-reviewed)abstract
- Random terpolymers were synthesized from the electron-rich unit thiophene as the donor and two electron-deficient units with complementary absorption as the acceptor. Polymer solar cells (PSCs) fabricated from these terpolymers were compared with those fabricated from the ternary blends of two alternating polymers to explore the best strategy for extending the light absorption range. The two approaches showed similar open-circuit voltages (Voc) but different short-circuit current densities (Jsc). The terpolymer strategy broadened the light absorption range and provided a high power conversion efficiency (PCE) of 5.8%. This is due to a high Jsc and high hole mobility. The device fabricated from the ternary blend exhibited a lower PCE (3.5%) compared to those fabricated from the terpolymers and alternating polymer blends due to the morphological incompatibility of the donor polymers. Our results illustrate the potential of the terpolymer systems as a promising strategy to effectively increase the light absorption and thereby performance of PSCs by combining two morphologically incompatible polymers.
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| 2. |
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| 3. |
- Li, Zhaojun, 1989, et al.
(author)
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9.0% power conversion efficiency from ternary all-polymer solar cells
- 2017
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In: Energy and Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:10, s. 2212-2221
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Journal article (peer-reviewed)abstract
- Integration of a third component into a single-junction polymer solar cell (PSC) is regarded as an attractive strategy to enhance the performance of PSCs. Although binary all-polymer solar cells (all-PSCs) have recently emerged with compelling power conversion efficiencies (PCEs), the PCEs of ternary all-PSCs still lag behind those of the state-of-the-art binary all-PSCs, and the advantages of ternary systems are not fully exploited. In this work, we realize high-performance ternary all-PSCs with record-breaking PCEs of 9% and high fill factors (FF) of over 0.7 for both conventional and inverted devices. The improved photovoltaic performance benefits from the synergistic effects of extended absorption, more efficient charge generation, optimal polymer orientations and suppressed recombination losses compared to the binary all-PSCs, as evidenced by a set of experimental techniques. The results provide new insights for developing high-performance ternary all-PSCs by choosing appropriate donor and acceptor polymers to overcome limitations in absorption, by affording good miscibility, and by benefiting from charge and energy transfer mechanisms for efficient charge generation.
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| 4. |
- Li, Zhaojun, 1989, et al.
(author)
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High-Performance and Stable All-Polymer Solar Cells Using Donor and Acceptor Polymers with Complementary Absorption
- 2017
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In: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 7:14
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Journal article (peer-reviewed)abstract
- To explore the advantages of emerging all-polymer solar cells (all-PSCs), growing efforts have been devoted to developing matched donor and acceptor polymers to outperform fullerene-based PSCs. In this work, a detailed characterization and comparison of all-PSCs using a set of donor and acceptor polymers with both conventional and inverted device structures is performed. A simple method to quantify the actual composition and light harvesting contributions from the individual donor and acceptor is described. Detailed study on the exciton dissociation and charge recombination is carried out by a set of measurements to understand the photocurrent loss. It is unraveled that fine-tuned crystallinity of the acceptor, matched donor and acceptor with complementary absorption and desired energy levels, and device architecture engineering can synergistically boost the performance of all-PSCs. As expected, the PBDTTS-FTAZ:PNDI-T10 all-PSC attains a high and stable power conversion efficiency of 6.9% without obvious efficiency decay in 60 d. This work demonstrates that PNDI-T10 can be a potential alternative acceptor polymer to the widely used acceptor N2200 for high-performance and stable all-PSCs.
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| 5. |
- Li, Zhaojun, 1989, et al.
(author)
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High-photovoltage all-polymer solar cells based on a diketopyrrolopyrrole-isoindigo acceptor polymer
- 2017
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 5:23, s. 11693-11700
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Journal article (peer-reviewed)abstract
- In this work, we synthesized and characterized two new n-type polymers PTDPP-PyDPP and PIID-PyDPP. The former polymer is composed of pyridine-flanked diketopyrrolopyrrole (PyDPP) and thiophene-flanked diketopyrrolopyrrole (TDPP). The latter polymer consists of PyDPP and isoindigo (IID). PIID-PyDPP exhibits a much higher absorption coefficient compared to the widely used naphthalene diimide (NDI)-based acceptor polymers, and its high-lying LUMO level affords it to achieve a high open-circuit voltage (Voc). As a result, an all-polymer solar cell (all-PSC) fabricated from a high band gap polymer PBDTTS-FTAZ as the donor and PIID-PyDPP as the acceptor attained a high Voc of 1.07 V with a power conversion efficiency (PCE) of 4.2%. So far, it has been one of the highest PCEs recorded from all-PSCs using diketopyrrolopyrrole (DPP)-based acceptors. Gratifyingly, no obvious PCE decay was observed in two weeks, unraveling good stability of the all-PSC. This work demonstrates that the electron-withdrawing PyDPP unit can be a promising building block for new acceptor polymers in all-PSCs.
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| 6. |
- Murto, Petri Henrik, 1984, et al.
(author)
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High performance all-polymer photodetector comprising a donor-Acceptor-Acceptor structured indacenodithiophene-bithieno[3,4-c] pyrroletetrone copolymer
- 2018
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In: ACS Macro Letters. - : American Chemical Society (ACS). - 2161-1653. ; 7:4, s. 395-400
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Journal article (peer-reviewed)abstract
- The synthesis of an acceptor polymer PIDT-2TPD, comprising indacenodithiophene (IDT) as the electron-rich unit and an interconnected bithieno[3,4-c]pyrrole-4,4′,6,6′-Tetrone (2TPD) as the electron-deficient unit, and its application for all-polymer photodetectors is reported. The optical, electrochemical, charge transport, and device properties of a blend of poly(3-hexylthiophene) and PIDT-2TPD are studied. The blend shows strong complementary absorption and balanced electron and hole mobility, which are desired properties for a photoactive layer. The device exhibits dark current density in the order of 10 -5 mA/cm 2 , external quantum efficiency broadly above 30%, and nearly planar detectivity over the entire visible spectral range (maximum of 1.1 × 10 12 Jones at 610 nm) under-5 V bias. These results indicate that PIDT-2TPD is a highly functional new type of acceptor and further motivate the use of 2TPD as a building block for other n-Type materials.
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