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Yongfang Li - One of the best experts on this subject based on the ideXlab platform.

  • High efficiency Polymer solar cells with efficient hole transfer at zero Highest occupied molecular orbital offset between methylated Polymer donor and brominated acceptor
    Journal of the American Chemical Society, 2020
    Co-Authors: Rui Wang, Yongfang Li, Shanshan Chen, Ziya Shang, Lei Meng, Chunfeng Zhang, Min Xiao, Changduk Yang
    Abstract:

    Achieving efficient charge transfer at small frontier molecular orbital offsets between donor and acceptor is crucial for High Performance Polymer solar cells (PSCs). Here we synthesize a new wide ...

  • a low cost and High Performance Polymer donor material for Polymer solar cells
    Nature Communications, 2018
    Co-Authors: Jianqi Zhang, Yongfang Li, Zhiguo Zhang
    Abstract:

    The application of Polymer solar cells requires the realization of High efficiency, High stability, and low cost devices. Here we demonstrate a low-cost Polymer donor poly[(thiophene)-alt-(6,7-difluoro-2-(2-hexyldecyloxy)quinoxaline)] (PTQ10), which is synthesized with High overall yield of 87.4% via only two-step reactions from cheap raw materials. More importantly, an impressive efficiency of 12.70% is obtained for the devices with PTQ10 as donor, and the efficiency of the inverted structured PTQ10-based device also reaches 12.13% (certificated to be 12.0%). Furthermore, the as-cast devices also demonstrate a High efficiency of 10.41% and the devices exhibit insensitivity of active layer thickness from 100 nm to 300 nm, which is conductive to the large area fabrication of the devices. In considering the advantages of low cost and High efficiency with thickness insensitivity, we believe that PTQ10 will be a promising Polymer donor for commercial application of Polymer solar cells.

  • High Performance Polymer solar cells with as prepared zirconium acetylacetonate film as cathode buffer layer
    Scientific Reports, 2015
    Co-Authors: Shusheng Li, Fuzhi Wang, Deping Qian, Yongfang Li
    Abstract:

    Low-work-function active metals are commonly used as cathode in Polymer solar cells (PSCs), but sensitivity of the active metals towards moisture and oxygen results in poor stability of the devices. Therefore, solution-proceessable and stable cathode buffer layer is of great importance for the application of PSCs. Here we demonstrate High Performance PSCs by employing as-prepared zirconium acetylacetonate (a-ZrAcac) film spin-cast from its ethanol solution as cathode buffer layer. The PSCs based on a low bandgap Polymer PBDTBDD as donor and PC60BM as acceptor with a-ZrAcac/Al cathode demonstrated an average power conversion efficiency (PCE) of 8.75% which is significantly improved than that of the devices with traditional Ca/Al cathode. The improved photovoltaic Performance is benefitted from the decreased series resistance and enhanced light harvest of the PSCs with the a-ZrAcac/Al cathode. The results indicate that a-ZrAcac is a promising High Performance cathode buffer layer for fabricating large area flexible PSCs.

  • perylene diimides a thickness insensitive cathode interlayer for High Performance Polymer solar cells
    Energy and Environmental Science, 2014
    Co-Authors: Zhiguo Zhang, Boyuan Qi, Zhiwen Jin, Dan Chi, Zhe Qi, Yongfang Li, Jizheng Wang
    Abstract:

    With the power conversion efficiency of Polymer solar cells (PSCs) approaching the milestone value of 10%, their instability associated with a low work function metal cathode, particularly in the presence of oxygen and moisture, becomes a critical issue for real applications. To alleviate the air-sensitive problem, two easy-accessible solution-processed, environmentally friendly organic small-molecule cathode interlayers, with perylene diimides (PDI) as the core and amino (PDIN) or amino N-oxide (PDINO) as the terminal substituent, are explored. Benefitting from the extended planar structure of the PDI units, the two interlayer materials show High conductivities of ∼10−5 S cm−1, which make them capable of functioning efficiently in a wide thickness range of 6 to 25 nm. This is the first time that thickness-insensitive small-molecule-based cathode interlayers are reported. It is also found that the work function tuning effect of the two PDI-based interlayers allows High work function metals (such as Au and Ag) to act as the cathode. With the conventional device structure with PTB7 as a donor and PC70BM as an acceptor, the PDINO-based devices exhibit an efficiency of 8.24% with Al as the top electrode and 8.16% with Ag as the top electrode, much Higher than that of the corresponding Ca/Al-based device (6.98%). The High efficiency of 8.35% is also achieved in the device with PTB7-Th as the donor. The success of the two PDI-interlayers indicates that π-delocalized planar structures with High electron affinities could be particularly useful in developing High-Performance organic interlayer materials.

  • indene c60 bisadduct a new acceptor for High Performance Polymer solar cells
    Journal of the American Chemical Society, 2010
    Co-Authors: Youjun He, Hsiang Yu Chen, Jianhui Hou, Yongfang Li
    Abstract:

    Polymer solar cells (PSCs) are commonly composed of a blend film of a conjugated Polymer donor and a soluble C60 derivative acceptor sandwiched between an ITO anode and a low-workfunction metal cathode. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) are the most widely used donor and acceptor materials, respectively. However, the low LUMO energy level of PCBM limits the open circuit voltage (Voc) of the P3HT-based PSCs to ca. 0.6 V. Here we synthesized a new soluble C60 derivative, indene−C60 bisadduct (ICBA), with a LUMO energy level 0.17 eV Higher than that of PCBM. The PSC based on P3HT with ICBA as acceptor shows a Higher Voc of 0.84 V and Higher power conversion efficiency (PCE) of 5.44% under the illumination of AM1.5, 100 mW/cm2, while the PSC based on P3HT/PCBM displays a Voc of 0.58 V and PCE of 3.88% under the same experimental conditions. The results indicate that ICBA is an alternative High-Performance acceptor and could be widely used in High-Performance ...

Yang Yang - One of the best experts on this subject based on the ideXlab platform.

  • interface investigation and engineering achieving High Performance Polymer photovoltaic devices
    Journal of Materials Chemistry, 2010
    Co-Authors: Limin Chen, Zheng Xu, Ziruo Hong, Yang Yang
    Abstract:

    The contact between the Polymer active layer and the electrode is one the most critical interfaces in Polymer solar cells. In this article, we report the progress of interface engineering in Polymer solar cell research, where the multiple functions of the interfacial materials will be discussed. The vertical composition profile in Polymer:fullerene blends is an emerging topic, and the interlayer effect on the vertical phase separation and device Performance will be Highlighted. We also discuss the energy level alignment at the bulk heterojunction (BHJ) interface, with the aim of providing a better understanding towards the route of High efficiency Polymer solar cells.

  • High Performance Polymer light emitting diodes doped with a red phosphorescent iridium complex
    Applied Physics Letters, 2002
    Co-Authors: Fangchung Chen, Yang Yang, Mark E. Thompson, Junji Kido
    Abstract:

    High efficiency has been achieved in Polymer light-emitting diodes (PLEDs) exhibiting red emission by doping a fluorescence host material, poly(vinylcarbazole) (PVK), with an iridium(III) complex, bis[2-(2′-benzothienyl)-pyridinato-N,C3′]iridium(acetylacetonate) (BtpIr). The electroluminescence spectrum has a maximum wavelength of 614 nm. The Highest external quantum efficiency is 3.3%. Due to its short triplet excited lifetime (∼5 μs), the quenching of the triplet exciton in BtpIr-doped PVK PLEDs has been shown to be suppressed compared to platinum(II)-2,8,12,17-tetraethyl- 3,7,13,18-tetramethylporphyrin-doped PVK PLEDs. 65% of the peak efficiency can be sustained at High-current density and at the very High brightness of 1350 cd/m2. We suggest that both triplet–triplet annihilation and polaron–triplet annihilation involves exciton quenching.

  • High Performance Polymer light emitting diodes fabricated by a low temperature lamination process
    Advanced Functional Materials, 2001
    Co-Authors: Shunchi Chang, Yang Yang
    Abstract:

    We report on the successful demonstration of High Performance Polymer light-emitting diodes (PLEDs) using a low temperature, plastic lamination process. Blue- and red-emitting PLEDs were fabricated by laminating different luminescent Polymers and organic compounds together to form the active media. This unique approach eliminates the issue of organic solvent compatibility with the organic layers for fabricating multi-layer PLEDs. In addition, a template activated surface process (TAS) has been successfully applied to generate an optimum interface for the low temperature lamination process. Atomic force microscopy analysis reveals a distinct difference in the surfaces created by the TAS and the spin-coating process. This observation coupled with the device data confirms the importance of the activated interface in the lamination process.

  • High Performance Polymer Light-Emitting Diodes Fabricated by a Low Temperature Lamination Process**
    Advanced Functional Materials, 2001
    Co-Authors: Tzung-fang Guo, Shunchi Chang, Seungmoon Pyo, Yang Yang
    Abstract:

    We report on the successful demonstration of High Performance Polymer light-emitting diodes (PLEDs) using a low temperature, plastic lamination process. Blue- and red-emitting PLEDs were fabricated by laminating different luminescent Polymers and organic compounds together to form the active media. This unique approach eliminates the issue of organic solvent compatibility with the organic layers for fabricating multi-layer PLEDs. In addition, a template activated surface process (TAS) has been successfully applied to generate an optimum interface for the low temperature lamination process. Atomic force microscopy analysis reveals a distinct difference in the surfaces created by the TAS and the spin-coating process. This observation coupled with the device data confirms the importance of the activated interface in the lamination process.

Junfeng Fang - One of the best experts on this subject based on the ideXlab platform.

Zhiguo Zhang - One of the best experts on this subject based on the ideXlab platform.

  • a low cost and High Performance Polymer donor material for Polymer solar cells
    Nature Communications, 2018
    Co-Authors: Jianqi Zhang, Yongfang Li, Zhiguo Zhang
    Abstract:

    The application of Polymer solar cells requires the realization of High efficiency, High stability, and low cost devices. Here we demonstrate a low-cost Polymer donor poly[(thiophene)-alt-(6,7-difluoro-2-(2-hexyldecyloxy)quinoxaline)] (PTQ10), which is synthesized with High overall yield of 87.4% via only two-step reactions from cheap raw materials. More importantly, an impressive efficiency of 12.70% is obtained for the devices with PTQ10 as donor, and the efficiency of the inverted structured PTQ10-based device also reaches 12.13% (certificated to be 12.0%). Furthermore, the as-cast devices also demonstrate a High efficiency of 10.41% and the devices exhibit insensitivity of active layer thickness from 100 nm to 300 nm, which is conductive to the large area fabrication of the devices. In considering the advantages of low cost and High efficiency with thickness insensitivity, we believe that PTQ10 will be a promising Polymer donor for commercial application of Polymer solar cells.

  • constructing a strongly absorbing low bandgap Polymer acceptor for High Performance all Polymer solar cells
    Angewandte Chemie, 2017
    Co-Authors: Zhiguo Zhang, Shanshan Chen, Yankang Yang, Jia Yao, Lingwei Xue, William Morrison, Changduk Yang
    Abstract:

    All-Polymer solar cells (all-PSCs) offer unique morphology stability for the application as flexible devices, but the lack of High-Performance Polymer acceptors limits their power conversion efficiency (PCE) to a value lower than those of the PSCs based on fullerene derivative or organic small molecule acceptors. We herein demonstrate a strategy to synthesize a High-Performance Polymer acceptor PZ1 by embedding an acceptor–donor–acceptor building block into the Polymer main chain. PZ1 possesses broad absorption with a low band gap of 1.55 eV and High absorption coefficient (1.3×105 cm−1). The all-PSCs with the wide-band-gap Polymer PBDB-T as donor and PZ1 as acceptor showed a record-High PCE of 9.19 % for the all-PSCs. The success of our Polymerization strategy can provide a new way to develop efficient Polymer acceptors for all-PSCs.

  • a near infrared non fullerene electron acceptor for High Performance Polymer solar cells
    Energy and Environmental Science, 2017
    Co-Authors: Lian Zhong, Zhiguo Zhang, Bhoj Gautam, Haijun Bin, Jiudong Lin, Zhanjun Zhang, Zuoquan Jiang, Kenan Gundogdu, Liangsheng Liao
    Abstract:

    Low-bandgap Polymers/molecules are an interesting family of semiconductor materials, and have enabled many recent exciting breakthroughs in the field of organic electronics, especially for organic photovoltaics (OPVs). Here, such a low-bandgap (1.43 eV) non-fullerene electron acceptor (BT-IC) bearing a fused 7-heterocyclic ring with absorption edge extending to the near-infrared (NIR) region was specially designed and synthesized. Benefitted from its NIR light harvesting, High Performance OPVs were fabricated with medium bandgap Polymers (J61 and J71) as donors, showing power conversion efficiencies of 9.6% with J61 and 10.5% with J71 along with extremely low energy loss (0.56 eV for J61 and 0.53 eV for J71). Interestingly, femtosecond transient absorption spectroscopy studies on both systems show that efficient charge generation was observed despite the fact that the Highest occupied molecular orbital (HOMO)–HOMO offset (ΔEH) in the blends was as low as 0.10 eV, suggesting that such a small ΔEH is not a crucial limitation in realizing High Performance of NIR non-fullerene based OPVs. Our results indicated that BT-IC is an interesting NIR non-fullerene acceptor with great potential application in tandem/multi-junction, semitransparent, and ternary blend solar cells.

  • perylene diimides a thickness insensitive cathode interlayer for High Performance Polymer solar cells
    Energy and Environmental Science, 2014
    Co-Authors: Zhiguo Zhang, Boyuan Qi, Zhiwen Jin, Dan Chi, Zhe Qi, Yongfang Li, Jizheng Wang
    Abstract:

    With the power conversion efficiency of Polymer solar cells (PSCs) approaching the milestone value of 10%, their instability associated with a low work function metal cathode, particularly in the presence of oxygen and moisture, becomes a critical issue for real applications. To alleviate the air-sensitive problem, two easy-accessible solution-processed, environmentally friendly organic small-molecule cathode interlayers, with perylene diimides (PDI) as the core and amino (PDIN) or amino N-oxide (PDINO) as the terminal substituent, are explored. Benefitting from the extended planar structure of the PDI units, the two interlayer materials show High conductivities of ∼10−5 S cm−1, which make them capable of functioning efficiently in a wide thickness range of 6 to 25 nm. This is the first time that thickness-insensitive small-molecule-based cathode interlayers are reported. It is also found that the work function tuning effect of the two PDI-based interlayers allows High work function metals (such as Au and Ag) to act as the cathode. With the conventional device structure with PTB7 as a donor and PC70BM as an acceptor, the PDINO-based devices exhibit an efficiency of 8.24% with Al as the top electrode and 8.16% with Ag as the top electrode, much Higher than that of the corresponding Ca/Al-based device (6.98%). The High efficiency of 8.35% is also achieved in the device with PTB7-Th as the donor. The success of the two PDI-interlayers indicates that π-delocalized planar structures with High electron affinities could be particularly useful in developing High-Performance organic interlayer materials.

Jizheng Wang - One of the best experts on this subject based on the ideXlab platform.

  • perylene diimides a thickness insensitive cathode interlayer for High Performance Polymer solar cells
    Energy and Environmental Science, 2014
    Co-Authors: Zhiguo Zhang, Boyuan Qi, Zhiwen Jin, Dan Chi, Zhe Qi, Yongfang Li, Jizheng Wang
    Abstract:

    With the power conversion efficiency of Polymer solar cells (PSCs) approaching the milestone value of 10%, their instability associated with a low work function metal cathode, particularly in the presence of oxygen and moisture, becomes a critical issue for real applications. To alleviate the air-sensitive problem, two easy-accessible solution-processed, environmentally friendly organic small-molecule cathode interlayers, with perylene diimides (PDI) as the core and amino (PDIN) or amino N-oxide (PDINO) as the terminal substituent, are explored. Benefitting from the extended planar structure of the PDI units, the two interlayer materials show High conductivities of ∼10−5 S cm−1, which make them capable of functioning efficiently in a wide thickness range of 6 to 25 nm. This is the first time that thickness-insensitive small-molecule-based cathode interlayers are reported. It is also found that the work function tuning effect of the two PDI-based interlayers allows High work function metals (such as Au and Ag) to act as the cathode. With the conventional device structure with PTB7 as a donor and PC70BM as an acceptor, the PDINO-based devices exhibit an efficiency of 8.24% with Al as the top electrode and 8.16% with Ag as the top electrode, much Higher than that of the corresponding Ca/Al-based device (6.98%). The High efficiency of 8.35% is also achieved in the device with PTB7-Th as the donor. The success of the two PDI-interlayers indicates that π-delocalized planar structures with High electron affinities could be particularly useful in developing High-Performance organic interlayer materials.

  • Layer-by-layer processed High-Performance Polymer solar cells
    Applied Physics Letters, 2012
    Co-Authors: Jizheng Wang
    Abstract:

    Layer-by-layer (LL) process has great potential in achieving High-Performance Polymer solar cells (PSCs) due to its advantage in realizing p-i-n like structure. LL method is attracting more and more interests in fabricating PSCs, and power conversion efficiency (PCE) of LL processed PSCs has been greatly improved to over 5% recently. In this paper, by employing LL approach, we fabricated Polymer photovoltaic devices with poly(3-hexylthiophene) (P3HT) as donor and four different fullerenes as acceptor. PCE of 6.48% was achieved. Performances of the LL processed devices are comparatively better than that of their corresponding traditional bulk-heterojunction devices.