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Tetraphenylethylene Substituted Thienothiophene and Dithienothiophene Derivatives; Synthesis, Optical Properties and OLED Devices
摘要： Thieno[3,2-b]thiophene (TT) and dithieno[3,2-b;3,2-d]thiophene (DTT) have drawn an immense attention in the field of electronics and optoelectronics. In this work, first examples of TTs (TPE2-TT, TPE3-TT) and DTT (TPE2-DTT), having tetraphenylethylene (TPE) at the peripherals for aggregation induced emission (AIE) applications at OLEDs, were designed and synthesized by Suzuki coupling reaction. Their properties were investigated through experimental and computational studies, as well as X-ray diffraction and DFT-optimization. TPE2-TT produced an excellent device performance with a maximum luminance of 11620 cd m-2, a maximum current efficiency of 6.17 cd A-1 and maximum external quantum efficiency of 2.43%. Moreover, these synthetically easy accessible molecules had high thermal stability, which make them perfectly suitable for optical applications.
关键词： Tetraphenylethylene,Aggregation Induced Emission,Dithieno[3,2-b;3,2-d]thiophene,Thieno[3,2-b]thiophene,OLED
更新于2025-09-23 15:21:01
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Wide-Band-Gap Phthalimide-Based D-π-A Polymers for Nonfullerene Organic Solar Cells: The Effect of Conjugated π-Bridge from Thiophene to Thieno[3,2- <i>b</i> ]thiophene
摘要： Conjugated polymers with D-π-A backbone structures have been intensively investigated and have largely promoted the rapid progress of organic solar cells (OSCs). However, as one of the simplest electron-accepting (A) units, phthalimide (PhI), only attracts less attention to construct promising D-π-A photovoltaic polymers in OSC community. Thus the correlations between the chemical structure-optoelectronic properties-photovoltaic performance need to be systematically investigated. Here, we combined the PhI moiety with the electron-donating (D) unit benzodithiophene (BDT) to synthesize two D-π-A copolymers PE80 and PE81, where the π-bridge corresponds to the thiophene (T) and thieno[3,2-b]thiophene (TT) respectively. When blended with a low bandgap (Eg=1.33 eV) non-fullerene acceptor Y6, PE81 achieved a power conversion efficiency (PCE) of 10.21% with an open circuit voltages (VOC) of 0.90 V, which are much higher than those of PE80:Y6 device (PCE = 4.11% and VOC = 0.88 V). Our results indicate that PhI is also a promising electron-deficient unit to construct photovoltaic polymers and using TT π-bridge is simple strategy to improve the photovoltaic performance of D-π-A polymers.
关键词： non-fullerene organic solar cells,D-π-A backbone,Conjugated polymers,thieno[3,2-b]thiophene,phthalimide
更新于2025-09-12 10:27:22
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Efficient non-fullerene polymer solar cells enabled by side-chain conjugated thieno[3,4-c]pyrrole-4,6-dione-based polymer and small molecular acceptors
摘要： The application of non-fullerene (NF) acceptors in bulk-heterojunction (BHJ) polymer solar cells (PSCs) is a promising approach to overcome the inherent drawbacks of fullerene derivatives-based acceptors. In PSCs, complementary absorption as well as matched molecular energy levels between the low bandgap acceptor-donor-acceptor (A-D-A) small molecular acceptor and medium/wide bandgap polymer donor is crucial to achieve high power conversion efficiency (PCE). Alternating polymers based on benzodithiophene (BDT) electron-donating segment and thieno[3,4-c]pyrrole-4,6-dione (TPD) electron-withdrawing segment own medium bandgap and low-lying highest occupied molecular orbital (HOMO) energy level, leading to presentable photovoltaic properties with fullerene derivatives. To probe into the performances of TPD-based polymers in NF-PSCs, two TPD-based polymers containing alkoxy or alkylthienyl modified benzo[1,2-b:4,5-b′]dithiophene (BDT) were synthesized and adopted as electron-donors and blended with A-D-A-type electron-acceptor 2,2′-[[6,6,12,12-tetrakis(4-hexylphenyl)-s-indacenodithieno[3,2-b]thiophene]methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)]]bis(propanedinitrile) (ITIC) to fabricate the corresponding photovoltaic devices. The two-dimensional conjugated polymer PBDTT-TPD shows enhanced extinction coefficient, deeper HOMO energy level and better hole transport performance, resulting in improved PCE of 6.17%. To further boost the performances of the polymers, a small molecular acceptor 2,2′-((2Z,2′Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl) bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC) with down-shifted energy level was also used to blend with the two polymers in PSCs. Despite the open-circuit voltage (VOC) of the PBDTT-TPD:IDIC-based device is slightly decreased, the short-circuit current density (JSC) and fill factor (FF) are simultaneously improved, yielding an promising PCE of 7.15%. These results indicate that two-dimensional conjugated TPD-based polymers can be potential application as medium bandgap polymeric donor to match with small molecular acceptors having suitable molecular energy levels to get high efficiency in PSCs.
关键词： Non-fullerene acceptors,Thieno[3,4-c]pyrrole-4,6-dione,Energy level offsets,Polymer solar cells,Thermal annealing
更新于2025-09-11 14:15:04
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Bicomponent-random Approach to Synthesis of Donor Polymers for Efficient All-Polymer Solar Cells Processed from A Green Solvent
摘要： All-polymer solar cells (all-PSCs) can offer unique merits of high morphological stability to thermal and mechanical stress. To realize its full potential as flexible or wearable devices, it is highly desirable that the all-PSCs can be fabricated from green solvent with simple post-treatment to avoid thermal annealing on flexible substrate. This proposed a severely challenge on material design to tune their properties with suitable solubility, aggregation, and morphology. To address this challenge, here, a simple bicomponent-random approach on a D-A-type polymer donor was developed by just varying the D-A molar ratio. Under this approach, a series of new random polymers PBDTa-TPDb with different molar ratio of D component of 2D-benzo[1,2-b:4,5-b']dithiophene (BDT) and A component of thieno[3,4-c]pyrrole-4,6-dione (TPD) were designed and synthesized. The energy levels, light absorption, solubility and packing structure of random donors PBDTa-TPDb were found to vary substantially with the various D-A molar ratio. The devices based PBDTa-TPDb/P(NDI2HD-T) were fabricated to explore the synergistic effects of processing solvent and composition of D-A-type random polymers. The results show that nanoscale morphology, balanced miscibility/crystallinity of blend and photovoltaic properties could be rationally optimized by tuning the composition of random donors. As a result, as-cast all-PSC based optimal donor PBDT5-TPD4 achieves a best power conversion efficiency (PCE) of 8.20% processed from green solvent, which performs better than that based reference polymer (PCE: 6.41%). This efficiency is the highest value for all-PSCs from BDT-TPD-based donors. Moreover, the optimized devices exhibited relatively insensitive to the thickness of the active layer and good stability.
关键词： thieno[3,4-c]pyrrole-4,6-dione,all-polymer solar cells,bicomponent-random approach,benzo[1,2-b:4,5-b']dithiophene,green solvent
更新于2025-09-11 14:15:04
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Electrochemical gating of a hydrophobic organic semiconductor with aqueous media
摘要： We show that even the highly hydrophobic semiconducting polymer poly [2,5-bis(3-tetradecylthiophen-2-yl) thieno[3,2-b]thiophene] (PBTTT) can operate in organic electrochemical transistor (OECT) rather than field effect (OFET) mode when gated with aqueous media. The required bulk penetration of anions into the semiconducting film within the electrochemical window of water is here enabled by the choice of anion, namely, picric acid (PA). OECT mode operation in PBTTT films or its analogues had previously been seen only when gated with solid electrolytes with a larger electrochemical window, or for PBTTT analogues with hydrophilic sidechains. We assign the ability of PA anions to penetrate bulk PBTTT from their similarity to PBTTT solvents (chlorinated benzenes), in the sense that they both display an electron-deficient π electron system. In control experiments, we confirm that OECT mode is not observed when gating PBTTT with another organic acid (acetic acid) that does not display such π electron system, and that the gating mechanism indeed is electrochemical doping rather than a charge transfer mechanism. OECT mode is observed only at rather high PA concentrations in an aqueous gate medium (50 mM or more), but when it is, it leads to conductivities of ≈ 80 S/cm, slightly larger than for a PBTTT analogue with hydrophilic side chains gated with chloride anions.
关键词： regioregular poly(3-hexithiophene),organic electrochemical transistor,Picric Acid,Poly [2,5-bis (3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]
更新于2025-09-10 09:29:36