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A new angular-shaped naphthodithiophene diimide (aNDTI) is designed and synthesized. The aNDTI-containing polymers are used as non-volatile additives to improve the efficiency of organic solar cells.

Tetraalkylammonium bromide is produced in situ. The effect of the length of bromoalkyl chains is recognized, indicating the importance of side-chain engineering. The hydrogen evolution rate is improved significantly by the presence of Pd.

The Grubbs G-I or G-II catalyst gives the ruthenium ethoxy carbene complex, which catalyzes ring-opening cross metathesis (ROCM) of a strained cyclic alkene to give a diene where one of the two alkene moieties in the product contains an ethoxy substituent. No polymeric products are detected. Hydrocarbons such as parent norbornene or substituted cyclopropenes can proceed with the reaction smoothly. Tertiary amines, N-alkylimides, esters, and aryl or alkyl bromides remain intact under the reaction conditions. In addition to vinyl ethers, vinylic esters can also be used. The time required to reach a 50% yield of the ROCM product t50 varies from 0.01 to 140 h depending on the strain and nucleophilicity of the double bond. Anchimeric participation of an electron-rich group would result in significant enhancement of the reactivity, and the t50 could be as short as several minutes. A similar substrate without such a neighboring group shows a much slower rate. An exo-norborne derivative reacts much faster than the corresponding endo-isomer. Alkenes with poor nucleophilicity are less favored for the ROCM process, so is less strained cyclooctene.

A plasma-based undoped-HfO2 FeFET (ferroelectric FET) with non-volatile memory characteristics is demonstrated. Modifying the O2 plasma period in plasma-enhanced atomic layer deposition (PE-ALD) is an effective approach to enhance the remnant polarization ( $\text{P}_{\text {r}}$ ) up to 2P $_{\text {r}} = 25\,\,\mu \text{C}$ /cm2 for the MFM (metal/ferroelectric/metal) structure with ferroelectric undoped-HfO2 thin films, and successful integration is implemented for the FeFET. The appropriate O2 vacancies ( $\text{V}_{\text {o}}^{{2}+}$ ) benefit the formation of the ferroelectric phase since they play the role of dopants and help orthorhombic phase (o-phase) formation during post-metal annealing (PMA). The $\text{V}_{\text {o}}^{{2}+}$ -rich undoped-HfO2 FeFET exhibits a memory window (MW) of 0.5 V, ${5} \times {10}^{{4}}$ switching endurance cycles, and higher than $10^{{4}}$ sec of data retention with $\text{V}_{\text {P/E}} = \pm 5$ V.

A plasma-based ferroelectric undoped HfO x capacitor is fabricated using plasma-enhanced atomic layer deposition (PE-ALD), and the multilevel characteristics of synaptic behavior are investigated. A gradual ferroelectric phase transition in the material is confirmed by grazing incidence X-ray diffraction (GI-XRD) for different O2 plasma periods. The metal–ferroelectric–metal (MFM) capacitor presents excellent remnant polarization ( ${\text{P}}_{r}$ ) up to $13~\mu \text{C}$ /cm2 and a switching endurance of more than 108 cycles. Superior small potentiation/depression nonlinearity ( $\alpha _{p}/\alpha _{d} = -0.08$ /−1.66 for voltage modulation stimulation) for synaptic training and almost symmetry training curve ( $\vert \alpha _{p}$ - $\alpha _{d}\vert $ ) are obtained. High stability under multilevel operation with five consecutive cycles of alternating potentiation and depression is exhibited without significant polarization variation for each training step (pulse).

In this work, P(NDI2OD-T2) was blended with various amounts of PEO, aPP, or iPP to furnish numerous thin films. The morphology of pristine P(NDI2OD-T2) and the blends was investigated by X-ray phot...

Two-dimensional alkylated αβ-TTN and βα-TTN were designed and synthesized. The cross-shaped αβ-TTN and βα-TTN moieties were polymerized to afford two isomeric polymers, Pαβ-TTNFBT40 and Pβα-TTNFBT4...

Three unsymmetrical diiodobichalcogenophenes SSeI2, STeI2, and SeTeI2 and a diiodoterchalcogenophene SSeTeI2 were prepared. Grignard metathesis of SSeI2, STeI2, SeTeI2, and SSeTeI2 occurred regioselectively at the lighter chalcogenophene site because of its relatively lower electron density and less steric bulk. Nickel-catalyzed Kumada catalyst-transfer polycondensation of these Mg species provided a new class of side-chain regioregular and main-chain AB-type alternating poly(bichalcogenophene)s—PSSe, PSTe, and PSeTe—through a chain-growth mechanism. The ring-walking of the Ni catalyst from the lighter to the heavier chalcogenophene facilitated subsequent oxidative addition, thereby suppressing the possibility of chain-transfer or chain-termination. More significantly, the Ni catalyst could walk over the distance of three rings (ca. 1 nm)—from a thiophene unit via a selenophene unit to a tellurophene unit—to form PSSeTe, the first ABC-type regioregular and periodic poly(terchalcogenophene) comprising three different types of 3-hexylchalcogenophenes., Three unsymmetrical diiodobichalcogenophenes SSeI2, STeI2, and SeTeI2 and a diiodoterchalcogenophene SSeTeI2 were prepared to synthesize a new class of polychalcogenophenes with precisely controlled sequences by catalyst-transfer polycondensation.

A first-generation Grubbs catalyst has been shown to not only catalyze the ring opening metathesis polymerization (ROMP) of cyclopropene derivatives but also differentiate E- and Z-double bonds in ...

A microplasma synthesis of diameter-controlled colloidal graphene quantum dots under ambient conditions is demonstrated. The GQD size was controlled by controlling the size of the organosulfate micelles. Experimental and theoretical results suggest that the organosulfate molecules within the micelles undergo nanographene nucleation and growth by solvated electrons during the synthesis.

Stromaphane is a new type of two-dimensional covalent organic framework (2D-COF), constituting of multiple layers of ladderphanes where two adjacent ladderphane motifs share a common polymeric backbone. The linkers for each ladderphane moiety are perpendicular to the polymeric backbones and staggered with the linkers in the immediate neighbouring ladderphane layers. The framework of the stromaphane contains numerous slit-shaped pores with a width in subnanometres and length in nanometers. This 2D-COF is synthesized by Grubbs G-I catalyst-mediated stereospecific ring opening metathesis polymerisation of a biscyclopropene derivative having a benzene triad linker. The overall process can be considered as a self-intercalation polymerisation of a biscyclopropene. The structure of the 2D-COF has been proved by XRD measurements, DFT simulation, and STM images. This 2D-COF is composed of substituted poly(methylene-E-vinylene) (PMEV) backbones and benzene triad linkers to form a two-dimensional framework with multiply symmetrically distributed subnanometric slit-shaped pores.

A new class of additive materials bis(pentafluorophenyl) diesters (BFEs) where the two pentafluorophenyl (C6F5) moieties are attached at the both ends of a linear aliphatic chain with tunable tether lengths (BF5, BF7, and BF13) were designed and synthesized. In the presence of the BF7 to restrict the migration of fullerene by hand-grabbing-like supramolecular interactions induced between the C6F5 groups and the surface of fullerene, the P3HT:PC61BM:BF7 device showed stable device characteristics after thermal heating at 150 oC for 25 h. The morphologies of the active layers were systematically investigated by OM, GISAXS, and AFM. The tether length between the two C6F5 groups plays a pivotal role in controlling the intermolecular attractions. BF13 with long and flexible tether might form a BF13-fullerene sandwich complex that fails to prevent fullerene’s movement and aggregation, while BF5 with too short tether length decreases the possibility of interactions between the C6F5 groups and the fullerenes. BF7...

ETS–NOCV charge and bond energy analyses have been carried out for a broad range of transition-metal carbonyl complexes L–[M], comprising different ligand classes, transition metals, and coordination geometries. The resulting electronic redistributions are visually assigned to σ donation, π backbonding, and related interactions. We propose a Hirshfeld partitioning of these electronic redistributions to afford the corresponding charge flow contributions Δqσ, Δqπ, etc. Taken together, a detailed picture of the dative bonding arises, in terms of both energetics and the extent of σ-electron donation and π-electron backbonding. The charge flows Δqσ and Δqπ appropriately quantify trends in the ligand σ-donor and π-acceptor abilities and are transferable across the transition-metal complexes studied and thus promise to be suitable descriptors for ligand knowledge bases. As a case in point, the TEP is well reproduced by the calculated νCO(A1) frequencies and is 3 times more strongly affected by Δqσ than by Δqπ, w...

Aqueous palladium-catalyzed direct arylation polymerization (DArP) of 2-bromothiophene derivatives 6-(2-(2-bromothiophen-3-yl)ethoxy)hexyl trimethylammonium bromide (T1) and 4-(2-(2-bromothien-3-yl)ethoxy)butylsulfonate (T2) is achieved. The supporting ligand, triphenylphosphine-3,3',3''-trisulfonic acid trisodium salt (m-TPPTs), facilitates DArP of both derivatives; however, its separation from the polymers by dialysis is difficult due to its strong aggregation in water and N,N-dimethylacetamide (DMAc). This is supported by dynamic light scattering, gel permeation chromatography (GPC), and single-crystal X-ray crystallography. Pyrimidine-Pd(OAc)2 is utilized in the DArP of T1 to afford PT1 without ligand contamination. Density functional theory calculations to determine the coordinating capability of the carboxylate/pivalic acid/water to palladium indicate the viability of implementing DArP in water. Finally, polyelectrolyte molecular-weight overestimation by GPC in water is attributed to the polyelectrolyte effect. Aggregation of the conjugated polyelectrolytes leads to a contracted hydrodynamic volume, and the molecular weight and dispersity assessed by GPC in DMAc significantly deviate from the actual values. An objective approach to evaluate the molecular weight for conjugated polyelectrolytes requires further development.

A systematic methodology is developed to construct the angular-shaped β-form naphthodithiophene (β-aNDT) core with regiospecific substitution of two alkyl groups at its 4,9- or 5,10-positions via the base-induced double 6π-cyclization of dithienyldieneyne precursors, leading to the two isomeric 4,9-β-aNDT and 5,10-β-aNDT monomers. It is found that a more curved geometry of the β-aNDT units intrinsically increases the solubility and thus the solution-processability of the resultant polymers. Therefore, β-aNDT units are ideal for polymerization with an acceptor-containing monomer without the need for any solubilizing aliphatic side chains, which are considered the insulating portion that jeopardizes charge transport. Based on this consideration, the 4,9- and 5,10-dialkylated β-aNDT monomers are polymerized with the non-alkylated DTFBT acceptor to afford two P4,9-βNDTDTFBT and P5,10-βNDTDTFBT copolymers for head-to-head comparison of the 4,9-inner/5,10-outer isomeric alkylation effect. It is found that 4,9-β-aNDT adopts a twisted conjugated structure due to the intramolecular steric repulsion between the inner branched side chains and the β-hydrogens on the thiophene rings. The slightly twisted 4,9-β-aNDT moiety allows P4,9-βNDTDTFBT to have higher solubility upon polymerization and thus a higher molecular weight, which eventually induces a higher ordered packing structure in the thin film compared to P5,10-βNDTDTFBT. As a result, P4,9-βNDTDTFBT exhibits a higher OFET mobility of 0.18 cm2 V−1 s−1, and the P4,9-βNDTDTFBT:PC71BM-based solar cell device also achieves a higher PCE of 7.23%, which is even better than the corresponding P4,9-αNDTDTFBT-based device.

A nonacylic building block TPTPT with the alternate thiophene and benzene subunits fastened by four bridging methylene groups was connected with various acceptors including diphenylquinoxaline ( QX ), thieno[3,4- c ]pyrrole-4,6(5H)-dione ( TPD ), thieno[3,4- b ]thiophene ( TT ) to afford donor-acceptor (D-A) alternating copolymers - PTPTPTQX , PTPTPTTPD , and PTPTPTTT and random copolymers - PTPTPTQX11 , PTPTPTQX12 , PTPTPTTPD11 , PTPTPTTPD12 , PTPTPTTT11 , and PTPTPTTT12 . The thermal, optical, and electrochemical properties of these copolymers were measured and compared. The random copolymers all have higher glass transition temperature ( T g ) than the corresponding alternating copolymers. ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) calculations suggest that the increase of planarity in the random copolymers arises from the introduction of thiophene units intercalating between donor and acceptor moieties. Bulk heterojunction (BHJ) polymer solar cells (PSCs) were fabricated on the basis of ITO/PEDOT:PSS/polymer:PC 71 BM/Ca/Al device configuration. When the acceptor is QX or TPD , the resultant alternating copolymers performed superior than the random counterparts. When the acceptor is TT , the high content of TT seems to be harmful to the device efficiency, which may relate with the strong quinoidal character of the TT unit. Overall, for the TPTPT core structure, in the used acceptors, the alternating-copolymer arrangement appears to be a better construction manner for the purpose of BHJ PSC applications.

A new tetracyclic 4,9-dialkyl angular-shaped naphthodiselenophene (4,9-α-aNDS) was designed and synthesized. The naphthalene core in 4,9-α-aNDS is formed by the DBU-induced 6π-cyclization of an (E)-1,2-bis(3-(tetradec-1-yn-1-yl)selenophen-2-yl)ethene intermediate followed by the second PtCl2-catalyzed benzannulation. This synthetic protocol allows for incorporating two dodecyl groups regiospecifically at 4,9-positions of the resulting α-aNDS. An ordered supramolecular self-assembly formed via noncovalent selenium–selenium interactions with a short contact of 3.5 A was observed in the single-crystal structure of 4,9-α-aNDS. The distannylated α-aNDS building block was copolymerized with Br-DTFBT and Br-DPP acceptors by Stille cross coupling to form two new donor–acceptor polymers PαNDSDTFBT and PαNDSDPP, respectively. The bottom-gate/top-contact organic field-effect devices using the PαNDSDTFBT and PαNDSDPP semiconductors accomplished superior hole mobility of 3.77 and 2.17 cm2 V–1 s–1, respectively, which ...

The ferroelectric characteristics of undoped hafnium oxide (HfO2) in titanium nitride (TiN)/HfO2/TiN stacks exhibited improved remanent polarization by controlling the nitrogen gas flow during TiN deposition in this work. Electrical measurements revealed that samples with a higher N2/(Ar + N2) ratio obtained a higher remanent polarization of approximately 10 μC/cm2 at 2.5 V but exhibited a larger leakage current and less reliability. Among all the samples, the sample with a N2/(Ar + N2) ratio of 33% exhibited a relatively high remanent polarization of 12 μC/cm2 and excellent endurance over 108 cycles. Through X-ray photoelectron spectroscopy (XPS) analysis, it was observed that increasing the N2 gas flow during TiN electrode deposition contributed to excessive N-diffusion, leading to the creation of more oxygen vacancies and subsequently to device failure. Therefore, controlling the appropriate N2 gas flow during TiN deposition is crucial to enhance the ferroelectric characteristics of undoped HfO2. The results of this study may be applicable to future work on nonvolatile memory applications.

Angular-shaped dialkyltetracenedithiophenes (aTDTs) undergo [4+4] photodimerization in solution to form a butterfly-shaped skeleton. This reaction proceeds in a regio- and stereo-selective manner, forming only a single planosymmetric syn-[2,2]-daTDT out of six possible products. The photocycloaddition of aTDTs can take place topochemically in the thin-film state while maintaining regio- and stereo-selectivity. Stronger aliphatic dispersion forces and π–π interactions play important roles in forming the eclipsed dimeric complex that leads to the syn-[2,2]-daTDT isomer.

Isomeric 2,8-distannyl 5,11-didodecyl αβ-TTN (1, tetrathienonaphthalene = TTN) and 2,8-didodecyl 5,11-distannyl αβ-TTN (2) have been designed and successfully synthesized. The naphthalene core structures in αβ-TTNs were constructed by a systematic protocol using PtCl2-catalyzed cyclization followed by oxidative Scholl annulation in good yields. Compared to the one-dimensional naphthodithiophene derivatives, the two-dimensional αβ-TTN molecules showed good solubility, extended conjugation, strong absorptivity, and highly coplanar structures. Compounds 1 and 2 were polymerized with a 5,5'-dibromo-2,2'-bithiophene-based monomer to afford 2,8-αβ-PTTNTT and 5,11-αβ-PTTNTT copolymers. 2,8-αβ-PTTNTT with the α-aNDT moiety in the main chain exhibited a higher hole mobility of 1.26 × 10(-2) cm(2) V(-1) s(-1).

We have designed and synthesized a tricyclic diseleno[3,2-b:2′,3′-d]silole (DSS) wherein the 3,3′-position of a biselenophene is bridged by a dioctylsilyl moiety. The distannylated DSS was copolymerized with a diketopyrrolopyrrole (DPP) acceptor to form a donor–acceptor copolymer PDSSDPP. The thiophene-based dithieno[3,2-b:2′,3′-d]silole (DTS) monomer and its corresponding copolymer PDTSDPP are also prepared as references for investigation of the chalcogen effect. Compared to PDTSDPP, PDSSDPP exhibits a more red-shifted absorption spectrum, a higher-lying HOMO energy level, and closer interchain packing associated with the more polarizable Se atom to induce stronger intermolecular interactions. The selenophene-based PDSSDPP shows a mobility of 2.47 × 10−2 cm2 V−1 s−1, which is nearly one order magnitude higher than the thiophene-based PDTSDPP with a mobility of 3.89 × 10−3 cm2 V−1 s−1. This result suggests that the DSS unit and its polymers are promising for OFET applications.

We present a facile synthesis method to make a new ladder-type heptacyclic dithienobenzofluorene (DTBF) framework, where the central 2,7-fluorene unit is covalently fastened with two external thiophenes via two CC bridges. A dieneyne-containing precursor undergoes DBU-induced double benzannulation to regiospecifically introduce two solubilizing 2-octyldodecyl side chains at 5,10-positions of DTBF. The rigid and coplanar Br-DTBF monomer with sufficient solubility was copolymerized with 5,6-difluoro-4,7-bis(5-(trimethylstannyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (Sn-DTFBT) and 5,10-bis(5-(trimethylstannyl)thiophen-2-yl)naphtho[1,2-c:5,6-c′]bis([1,2,5]thiadiazole) (Sn-DTNT) via Stille coupling to furnish two donor–acceptor copolymers, PDTBFFBT and PDTBFNT, respectively. Their thermal, optical, electrochemical, molecular stacking and photovoltaic properties are investigated. PDTBFNT has a higher molecular weight, smaller optical and electrochemical band gaps, and stronger solid-state packing than PDTBFFBT. DFT calculations were carried out to gain insight into the electronic and structural properties of DTBF and its derivatives. Bulk heterojunction solar devices with the ITO/ZnO/polymers:PC71BM/MoO3/Ag configuration were fabricated. By adding 5 vol% diphenyl ether (DPE) as an additive, PDTBFNT:PC71BM and PDTBFFBT:PC71BM devices achieved the power conversion efficiencies of 5.22% and 2.68%, respectively. The superior efficiency of PDTBFNT over PDTBFFBT is attributed to the better LUMO energy alignment between PDTBFNT and PC71BM and the face-on π-stacking of PDTBFNT in the active layer. Moreover, PDTBFNT exhibited a higher field-effect transistor hole mobility of 1.90 × 10−2 cm2 V−1 s−1 than PDTBFFBT with a value of 3.96 × 10−3 cm2 V−1 s−1.

Non-conjugated triethylene glycol (3-EG), tetraethylene glycol (4-EG) and pentaethylene glycol (5-EG) are presented as new cathode modification materials to achieve high-performance inverted-PCSs. By spin-coating from a non-chlorinated solvent, these small molecules can self-assemble on ITO via surface coordination and hydrogen bonding to form an ultra-thin layer. Theoretical simulations reveal that the coordination of oxygen atoms in the EG molecules to indium moieties on the ITO surface is the major mechanism in inducing interfacial dipoles, thereby reducing the work function (WF) of ITO for efficient electron collection. Based on the PBDTTT-EFT:PC71BM blend, the bulk heterojunction device using the 5-EG layer exhibited a higher short-circuit current density (Jsc) of 15.27 mA cm−2, fill factor (FF) of 0.69, and power conversion efficiency (PCE) of 8.46%, which are better than those of the corresponding devices using either inorganic ZnO or non-conjugated poly(ethylene oxide) (PEO) as the cathode buffer layer. More importantly, this simple and expedited strategy is also demonstrated to be universally applicable to various p-type conjugated polymers. The EG oligomers with well-defined chemical structures have the advantages of easy availability, simple processability and good device reproducibility, which are crucial keys for future commercialization using large-scale roll-to-roll production.

An angular-shaped and isomerically pure 4,10-di(2-octyl)dodecylanthradiselenophene (aADS) was successfully developed. The expedient synthesis to form the framework of aADS with two lateral side chains regioselectively at its 4,10-positions is via a base-induced propargyl–allenyl isomerization/6π-electrocyclization/aromatization protocol. This pentacyclic distannylated aADS unit was then copolymerized with dithienyldiketopyrrolopyrrole (DPP) and dithienyl-5,6-difluoro-2,1,3-benzothiadiazole (DTFBT) acceptors with different alkyl side chains to afford four donor–acceptor copolymers: PaADSDPP, PaADSDTFBT-C4, PaADSDTFBT-C8, and PaADSDTFBT-C8C12. UV–vis spectroscopy and cyclic voltammetry revealed that PaADSDPP has the narrowest energy band gap, and PaADSDTFBT-C8C12 has larger band gap than PaADSDTFBT-C4 and PaADSDTFBT-C8. Two layer ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) calculations were implemented to investigate the disparity in optical, electrochemical, and device pr...

Direct C–H arylation polymerization of 2-bromo-3-hexylselenophene and 2-bromo-3-hexylthiophene catalyzed by N-heterocyclic carbene (NHC) palladium-based and Pd(OAc)2-based systems has been carried out and investigated. Under the optimized conditions, high molecular weight poly(3-hexylthiohphene) (P3HT) (Mn = 26.9K g/mol) with high head-to-tail regioregularity (94%) can be obtained by using [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]chloro[3-phenylallyl]palladium(II) (Pd-IPr) as the catalyst. Pd-IPr exhibits a wide range of working temperatures from 70 to 140 °C and good catalytic reproducibility as a result of its high thermal stability. It was found that the presence of additional phosphine ligand, such as tris(o-methoxyphenyl)phosphine, can increase the polymerization efficiency in the Pd(OAc)2 system. This improvement is linked to the stability enhancement for the active species during the course of catalysis. For the first time, poly(3-hexylselenophene) (P3HS) was also obtained by direct-arylat...

A triarylamine-based material DVTPD containing two styryl groups has been developed. Upon isothermal heating at 180 °C for 30 min, DVTPD can be thermally cross-linked to form a solvent-resistant layer to realize the fabrication of solution-processed multilayer devices. The crosslinked DVTPD (denoted as X-DVTPD) layer possesses not only hole-collecting ability (HOMO = −5.3 eV) but also electron-blocking capability (LUMO = −2.2 eV). By incorporation of an ionic dopant, 4-isopropyl-4′-methyldiphenyliodonium tetrakis(pentafluorophenylborate) (DPITPFB), into the X-DVTPD material (1 : 10 in wt%), a favourable morphology of the dopant/matrix layer was formed and the hole-mobility is significantly improved by three orders of magnitude compared to its non-doped state. This DPITPFB : X-DVTPD (1 : 10 in wt%) layer was employed as the hole-transporting layer to fabricate polymer solar cell devices (PSCs). The EHOMO of the polymer in the active layer relative to the EHOMO of the X-DVTPD (−5.3 eV) governs the hole transportation highly associated with the device performance. The higher-lying EHOMO (−5.0 eV) of P3HT causes a large energy barrier for the hole transportation at the interface, leading to an unsatisfactory efficiency. The EHOMO level of the PTB7 copolymer (−5.15 eV) is closer to −5.3 eV. As a result, the PTB7-based device can achieve 80% of the efficiency obtained from the corresponding PEDOT:PSS-based device. Furthermore, the PBDCPDTFBT copolymer has the same EHOMO (−5.3 eV) with X-DVTPD. Consequently, the PBDCPDTFBT-based device showed a comparable efficiency of 5.3% to the corresponding PEDOT:PSS-based device. More importantly, PNDTDTFBT having the lowest-lying EHOMO of −5.4 eV exhibits superior performance with a high PCE of 6.64%, outperforming its reference PEDOT:PSS-based device. This simple and useful hole-transporting system integrating the crosslinking and doping strategies to replace PEDOT:PSS can be widely used in solution-processed organic electronic devices.

A single isomer of fullerene bisadduct, PC61PF, was obtained from commercially available fullerene derivative, PC61BM, in one pot over two steps. The tether-directed remote functionalization approach provided a very simple and fast method to produce a single isomer of fullerene bisadduct with good yield and easy purification. Bulk heterojunction organic solar cells containing the bisadduct was fabricated and tested.

A new polymer PDTFDPP20 based on dithieno[3,2-b:6,7-b′]fluorene (DTF) unit was developed. This polymer with a face-on orientation has achieved a high field-effect mobility up to 5 cm2 V–1 s–1., A ladder-type dithieno[3,2-b:6,7-b′]fluorene (DTF), where the central fluorene is fused with two outer thiophene rings at its 2,3- and 6,7-junctions, is developed. The pentacyclic DTF monomers were polymerized with dithienodiketopyrrolopyrrole (DPP) acceptors to afford three alternating donor–acceptor copolymers PDTFDPP16, PDTFDPP20, and PDTFDPP32 incorporating different aliphatic side chains (R1 group at DTF; R2 group at the DPP moieties). The side-chain variations in the polymers play a significant role in determining not only the intrinsic molecular properties but also the intermolecular packing. As evidenced by the 2-dimensional GIXS measurements, PDTFDPP16 with octyl (R1) and 2-ethylhexyl (R2) side chains tends to align in an edge-on π-stacking orientation, whereas PDTFDPP20 using 2-butyloctyl (R1) and 2-ethylhexyl (R2) adopts a predominately face-on orientation. PDTFDPP32 with the bulkiest 2-butyloctyl (R1) and 2-octyldodecyl (R2) side chains shows a less ordered amorphous character. The OFET device using PDTFDPP20 with a face-on orientation determined by GIXS measurements achieved a high hole-mobility of up to 5 cm2 V–1 s–1. The high rigidity and coplanarity of the DTF motifs play an important role in facilitating intramolecular 1-dimensional charge transport within the polymer backbones. The implementation of main-chain coplanarity and side-chain engineering strategies in this research provides in-depth insights into structure–property relationships for guiding development of high-mobility OFET polymers.

In this work, a combined approach was used to obtain a low-cost material for organic electronics by focusing on inexpensive monomers, short synthetic pathway, high-yielding polymerization method, low waste, and easy scalability. To achieve this, a new material, poly[isoindigo-alt-3,4-ethylenedioxythiophene], was synthesized using direct (hetero)arylation polymerization (DHAP). Only a few synthetic steps are required to obtain this material, and no organometallic intermediates are used. In order to make a bigger step toward a truly inexpensive technology, continuous flow methods were applied for the first time to DHAP. This method helped solving a common problem encountered in conjugated polymers synthesis, namely, batch-to-batch variations. Electronic properties of this polymeric material were evaluated using field effect transistors (μh = 7 × 10-3 cm2·V-1·s-1) and solar cells (η = 3.0%).

A new class of heptacyclic ladder-type terbenzodithiophene (TBDT) structures merging three fused benzodithophenes was developed. Two TBDT conjugated isomers, named as syn-TBDT and anti-TBDT, where the two thienyl rings in the outmost BDT units are in the syn- and anti-fashion, are designed. Two decyl groups are introduced to their 6,13 and 7,14-positions to form four isomeric 6,13-syn-TBDT, 7,14-syn-TBDT, 6,13-anti-TBDT, and 7,14-anti-TBDT structures which are constructed by the DBU-induced 6-benzannulation involving propargyl-allenyl isomerization of the dieneyne moieties in the corresponding precursors followed by 6π-electrocyclization/aromatization, while isomeric TD-syn-TBDT and TD-anti-TBDT with four decyl groups substituted at 6,7,13,14-positions are synthesized via palladium-catalyzed dialkylacetylene insertion/C-H arylation of the corresponding iodobiaryl precursors. The intrinsic properties can be modulated by molecular manipulation of the main-chain and side-chain isomeric structures. anti-TBDT derivatives exhibit higher melting points, larger bandgaps, stronger intermolecular interactions, and higher mobility than the corresponding syn-TBDT analogues. These molecules can be further utilized as building blocks to make various TBDT-based materials for optoelectronic applications.