Goldansaz, Hadi; Jangizehi, Amir; Nikravan, Goolia; Verkinderen, Olivier; Goderis, Bart; Ghaffarian, Seyed Reza; van Ruymbeke, Evelyne; Ahmadi, Mostafa
Rheological modifiers based on supramolecular block copolymers: From weak associations to interconnected micelles
The rheological spectra of poly(n-butyl acrylate) in the presence of a series of P(nBA-b-HEMA) rheology modifiers show a two-step relaxation process originating from the PnBA matrix and the self-assemblies. The HEMA segments are further grafted with strong, hydrogen bonding UPy groups, which both magnifies and slows down the relaxation of…
Highly Ordered Semiconducting Polymer Arrays for Sensitive Photodetectors
Wei, Xiao; Gao, Hanfei; Feng, Jiangang; Pi, Yueyang; Zhang, Bo; Zhai, Yu; Wen, Wen; He, Mingqian; Matthews, James R.; Wang, Hongxiang; Li, Yang; Jiang, Shimei; Jiang, Lei; Wu, Yuchen
Semiconducting conjugated polymers possess attractive optoelectronic properties and low-cost solution processability and are inherently mechanically flexible. However, the device performance is susceptible to the fabrication methods because of the relatively weak intermolecular interaction of the polymers and their inherent conformational and energetic disorder. An efficient fabrication technique
Large Crystalline Domains and an Enhanced Exciton Diffusion Length Enable Efficient Organic Solar Cells
Zhang, Yiwei; Sajjad, Muhammad T.; Blaszczyk, Oskar; Parnell, Andrew J.; Ruseckas, Arvydas; Serrano, Luis A.; Cooke, Graeme; Samuel, Ifor D. W.
We studied crystallinity and exciton harvesting in bulk heterojunctions of the semiconducting polymer PffBT4T-2OD and electron acceptor PC71BM that are used to make highly efficient organic solar cells. Grazing incidence wide-angle X-ray scattering shows that the size of crystalline domains of PffBT4T-2OD increases to ?18 nm in photovoltaic blends upon…
Overcoming the energy loss in asymmetrical non-fullerene acceptor-based polymer solar cells by halogenation of polymer donors
Fan, Qunping; Liu, Tao; Gao, Wei; Xiao, Yiqun; Wu, Jingnan; Su, Wenyan; Guo, Xia; Lu, Xinhui; Yang, Chuluo; Yan, He; Zhang, Maojie; Li, Yongfang
To achieve efficient polymer solar cells (PSCs), it is important to overcome the energy loss (Eloss) from the optical bandgap to the open-circuit voltage (Voc) of the device by properly matching donor/acceptor (D/A) photovoltaic materials. Here, we develop efficient PSCs based on the absorption complementary pairs of halogenated polymer donors…
OrderOrder Phase Transitions Induced by Supercritical Carbon Dioxide in Triblock Copolymer Thin Films
Abate, Anabella A.; Vu, Giang Thi; Piqueras, Cristian M.; del Barrio, María Cecilia; Gómez, Leopoldo R.; Catalini, Gabriel; Schmid, Friederike; Vega, Daniel A.
We study the influence of supercritical carbon dioxide (scCO2) on the phase behavior of a cylinder-forming polystyrene-block-polybutadiene-b-polystyrene triblock copolymer thin film. Solvent annealing with scCO2 can produce patterns with long-range order but these structures become unstable for thin films with small thicknesses. These results are in good agreement with self-consistent…
Highly Crystalline Near-Infrared Acceptor Enabling Simultaneous Efficiency and Photostability Boosting in High-Performance Ternary Organic Solar Cells
Yin, Hang; Zhang, Chujun; Hu, Hanlin; Karuthedath, Safakath; Gao, Yajun; Tang, Hua; Yan, Cenqi; Cui, Li; Fong, Patrick W. K.; Zhang, Zhuoqiong; Gao, Yaxin; Yang, Junliang; Xiao, Zuo; Ding, Liming; Laquai, Frédéric; So, Shu Kong; Li, Gang
The near-infrared (NIR) absorbing fused-ring electron acceptor, COi8DFIC, has demonstrated very good photovoltaic performance when combined with PTB7-Th as a donor in binary organic solar cells (OSCs). In this work, the NIR acceptor was added to state-of-the-art PBDBT-2F:IT4F-based solar cells as a third component, leading to (i) an efficiency increase…
CO2-Triggered and temperature-switchable crystallization-driven self-assembly of a semicrystalline block copolymer in aqueous medium
Zhu, Rui; Luo, Xinjie; Feng, Yujun; Billon, Laurent
The synthesis of a semicrystalline block copolymer comprising a hydrophilic poly(acrylic acid) (PAA) pure block and an amphiphilic poly(acrylic acid)-r-poly(octadecyl acrylate) (PAA-r-PODA) random block by nitroxide-mediated polymerization (NMP) is reported. The aggregation behavior of the copolymer in aqueous medium was studied by using a MicroCal VP differential scanning calorimeter (VP-DSC)
Determination of the Critical Size of Secondary Nuclei on the Lateral Growth Front of Lamellar Polymer Crystals
Zhang, Shujing; Han, Jiarui; Gao, Yang; Guo, Baohua; Reiter, Günter; Xu, Jun
Nucleation is the rate-limiting first step of crystallization. The energy barrier related to form the critical nucleus predominantly affects the nucleation rate. Determination of the size of the critical nucleus is a key for understanding the mechanism of nucleation and allows testing theories. However, it has been a great challenge…
Revisiting the Role of Graphene Quantum Dots in Ternary Organic Solar Cells: Insights into the Nanostructure Reconstruction and Effective Förster Resonance Energy Transfer
Sung, Sae Jin; Kim, Jae Ho; Gihm, Se Hoon; Park, Jisoo; Cho, Young Shik; Yang, Seung Jae; Park, Chong Rae
Recent studies have introduced the graphene quantum dot (GQD) as a third material for the bulk-heterojunction polymer:fullerene solar cell (PSC) to improve light conversion efficiency. Although exciton generation/dissociation and carrier transport in the GQD-incorporated light-absorbing layer are strongly influenced by the ternary component, detailed analysis on the role of GQD…
Mechanical Properties and Failure Behavior of Physically Assembled Triblock Copolymer Gels with Varying Midblock Length
Mishra, Satish; Prado, Rosa M. Badani; Zhang, Song; Lacy, Thomas E.; Gu, Xiaodan; Kundu, Santanu
Mechanical properties including the failure behavior of physically assembled gels or physical gels are governed by their network structure. To investigate such behavior, we consider a physical gel system consisting of poly(styrene)-poly(isoprene)-poly(styrene) in mineral oil. In these gels, the endblock (PS) molecular weights are not significantly different, whereas, the midblock…