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Enhanced Photovoltaic Performance by Synergistic Effect of Chlorination and Selenophene ??-Bridge
摘要： In the rapid innovation of organic solar cells, polymer donor plays a significant role in achieving high power conversion efficiencies (PCEs). The strong intermolecular interactions and deep highest occupied molecular orbitals (HOMOs) of donor polymers will facilitate the favorable phase separation and high open-circuit voltage (Voc), resulting in the dramatic improvement of device performance. Herein, combined chlorination of 4,8-bis(thiophene-2-yl)-benzo[1,2-b:4,5-b′]-dithiophene (T-BDT) and selenophene π-bridges, a new polymer donor, named PBBSe-Cl, is designed and synthesized. Compared to its parent polymer without chlorine substitution and π-bridge (named PBB), PBBSe-Cl exhibits much stronger absorption, better molecular planarity, and improved molecular aggregations. Moreover, PBBSe-Cl shows favorable phase separation and bicontinuous interpenetrating network when blending with acceptor Y6. As a result, the inverted device based on PBBSe-Cl achieves a decent PCE of 14.44%, with synchronously improved short-circuit current density (Jsc) of 24.07 mA cm?2 and fill factor (FF) of 73.16%. However, its parent polymers PBB and PBBSe-H only present a relatively low device performance. In addition, a very low energy loss (Eloss) of 0.51 eV is realized for PBBSe-Cl-based devices. This investigation proves that introducing chlorine atoms on the conjugated side chains and selenophene π-bridges will stepwise increase the polymer solar cell efficiency due to the simultaneous enhancement of device current density and fill factor. The proper usage of chlorination and selenophene π-bridge is a facile and efficient strategy for high-performance solar conversion materials.
关键词： selenophene π-bridges,organic solar cells,power conversion efficiencies,chlorination,polymer donor
更新于2025-09-23 15:19:57
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Naphthalene Diimide-Based Terpolymers with Controlled Crystalline Properties for Producing High Electron Mobility and Optimal Blend Morphology in All-Polymer Solar Cells
摘要： We report a series of new n-type random copolymers (P(NDI2OD-Se-Th x) where x = 0, 0.5, 0.7, 0.8, 0.9, 1.0) consisting of naphthalene diimide (NDI), selenophene-2,2’-thiophene (Se-Th), and seleno[3,2-b]thiophene (SeTh) to demonstrate their use in producing efficient all-polymer solar cells (all-PSCs) and organic field-effect transistors (OFETs). To investigate the effect of polymer crystallinity on the performance of all-PSCs and OFETs, we tuned the composition of the Se-Th and SeTh moieties in the P(NDI2OD-Se-Th x) polymers, resulting in enhanced crystalline properties with higher Se-Th ratio. Thus, the OFET electron mobility was increased with higher Se-Th ratio, exhibiting the highest value of 1.38×10?1 cm2 V?1 s?1 with P(NDI2OD-Se-Th 1.0). However, the performance of all-PSCs based on PBDB-T:P(NDI2OD-Se-Th x) showed a non-linear trend relative to the Se-Th ratio and the performance was optimized with P(NDI2OD-Se-Th 0.8) exhibiting the highest power coversion efficiency of 8.30%. This is attributed to the stronger crystallization-driven phase separation in all-polymer blends for higher Se-Th ratio. At the optimal crystallinity of P(NDI2OD-Se-Th 0.8) in all-PSCs, the degree of phase separation, domain purity and the electron mobility were optimized, resulting in enhanced charge generation and transport. Our works describe structure-property-performance relationships to design effective n-type polymers in terms of crystalline and electrical properties suitable for both efficient OFETs and all-PSCs.
关键词： organic field-effect transistors,seleno[3,2-b]thiophene,polymer crystallinity,n-type random copolymers,selenophene-2,2’-thiophene,charge generation,all-polymer solar cells,charge transport,naphthalene diimide
更新于2025-09-19 17:13:59
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Achieving high-performance non-halogenated nonfullerene acceptor-based organic solar cells with 13.7% efficiency <i>via</i> a synergistic strategy of an indacenodithieno[3,2- <i>b</i> ]selenophene core unit and non-halogenated thiophene-based terminal group
摘要： An outmost selenophene-functionalized electron-rich central core (indacenodithieno[3,2-b]selenophene) and a new non-halogenated A–D–A architecture non-fullerene small molecular acceptor (NF-SMA) (TSeTIC) based on indacenodithieno[3,2-b]selenophene as the central unit and thiophene-fused IC as a terminal group was designed and synthesized for high performance organic solar cells. In contrast to the similar NF-SMA (TTTIC) with an indacenodithieno[3,2-b]thiophene unit, TSeTIC exhibited a stronger and red-shifted absorption spectrum, higher highest occupied molecular orbital (HOMO) energy level, and enhanced electron mobility in neat thin films. Furthermore, a TSeTIC/PM6-based device presented higher hole/electron mobility, better phase separation features with favorable morphology, and higher charge dissociation and collection efficiency than a TTTIC/PM6-based device, resulting in remarkably improved Jsc and FF without sacrificing the Voc. Therefore, compared to the best PCE of 12.05% with an energy loss (Eloss) of 0.64 eV for the PM6/TTTIC device, the optimized PM6/TSeTIC device yields a significantly higher PCE of 13.71% with a higher FF of 75.9% and decreased Eloss of 0.60 eV. It is worth noting that the excellent PCE of 13.71% is the highest recorded for A–D–A structural NF-SMAs with thiophene-containing terminal groups for binary organic solar cells. These results demonstrate that the synergistic strategy of using an indacenodithieno[3,2-b]selenophene core unit and thiophene-containing IC end group is a promising avenue to enhance the PCE of non-halogenated NF-SMAs with high Voc and FF as well as low Eloss.
关键词： indacenodithieno[3,2-b]selenophene,non-halogenated nonfullerene acceptor,organic solar cells,synergistic strategy,thiophene-based terminal group
更新于2025-09-16 10:30:52
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High-yielding Pd <sub/>2</sub> (dba) <sub/>3</sub> ·C <sub/>6</sub> H <sub/>6</sub> -based four-fold Sonogashira coupling with selenophene-conjugated magnesium tetraethynylporphyrin for organic solar cells
摘要： A catalytic system using Pd2(dba)3$(C6H6)/PPh3/CuI for Sonogashira coupling was demonstrated to synthesize a selenophene-conjugated magnesium tetraethynylporphyrin Mg-TEP-(Se-DPP)4 (2a). The terminal alkynes of magnesium tetraethynylporphyrin with bromoselenophene-tethered diketopyrrolopyrroles (DPPs) to produce the desired star-shaped 2a in 80% yield. This molecule shows higher solubility in organic solvents, more efficient visible and near-infrared region absorption, and a narrower band gap compared with reference thiophene-conjugated congeners. Two strategies, namely, selenium substitution and end-capping, were investigated to optimize bulk heterojunction structures in the active layers of organic solar cells. The optimized device based on 2a:PC61BM exhibited the highest PCE of 6.09% among the tested devices after solvent vapor annealing, owing to efficient exciton dissociation, balanced carrier mobility, and suppressed carrier recombination in the film's ordered morphology.
关键词： end-capping,selenium substitution,Sonogashira coupling,selenophene-conjugated magnesium tetraethynylporphyrin,organic solar cells
更新于2025-09-16 10:30:52
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Impact of Precise Control over Microstructure in Thiophene–Selenophene Copolymers
摘要： Controlling the sequence of repeat units in a synthetic polymer has been a long-standing topic of interest in chemistry. As methods to regulate sequence become more sophisticated, it is critical to consider how controlling the arrangement of repeat units along the polymer backbone impacts properties. In this work, thiophene?selenophene copolymers (statistical and periodic) were compared to elucidate the impact of periodicity on electronic properties and structural organization in conjugated macromolecules. Polymers were synthesized using catalyst-transfer polycondensation (CTP) enabling control over molecular weight and dispersity. The study revealed that optical bandgaps and redox potentials of periodic and statistical copolymers varied with composition in a predictable manner, regardless of monomer ordering along the chain. While the bandgaps of the two types of copolymers were indistinguishable, X-ray scattering revealed di?erences in solid-state packing. Both types of copolymers exhibited well-de?ned morphologies, but larger π-stacking distances and more orientational disorder were evident in the statistical systems. This indicates periodicity is an attribute that should be considered when synthesizing semiconducting materials.
关键词： solid-state packing,periodicity,electronic properties,thiophene?selenophene copolymers,catalyst-transfer polycondensation
更新于2025-09-10 09:29:36