Donor Backbone Research Articles

An effective strategy to design high-performance wide bandgap polymer donors for organic solar cells by increasing the backbone curvature

Although wide bandgap (WBG) polymer donors are widely used in non-fullerene organic solar cells (OSCs), only a few WBG polymers exhibited high power conversion efficiencies (PCEs). Developing WBG donors with ideal complementary absorption with narrow bandgap non-fullerene acceptors is critical to further improving the photovoltaic performance of OSCs. Here, we provide an effective strategy to widen the bandgap (Eg) of polymers by increasing the curvature of the polymer donor backbone structure and compare it with the fluorination strategy. Both experimental and theoretical results demonstrated that the fluorination strategy reduced the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of PBDT-DT2FBT with little effect on the Eg. In contrast, the polymer PBDT-DTfBT, with a large backbone curvature, exhibited a reduced HOMO energy level and a significantly increased LUMO energy level, resulting in a significant increase in the optical Eg of 0.19 eV. The PBDT-DTfBT-based device achieved a high PCE of 15.89%, which far exceeded the PCEs of the PBDT-DTBT (9.84%) and PBDT-DT2FBT-based devices (8.02%). This work could guide the design of high-performance WBG donors.

Catalytic oxidation properties of an acid-resistant cross-bridged cyclen Fe(II) complex. Influence of the rigid donor backbone and protonation on the reactivity.

The catalytic properties of an iron complex bearing a pentadentate cross-bridged ligand backbone are reported. With H2O2 as an oxidant, it displays moderate conversions in epoxidation and alkane hydroxylation and satisfactory ones in aromatic hydroxylation. Upon addition of an acid to the reaction medium, a significant enhancement in aromatic and alkene oxidation is observed. Spectroscopic analyses showed that accumulation of the expected FeIII(OOH) intermediate is limited under these conditions, unless an acid is added to the mixture. This is ascribed to the inertness induced by the cross-bridged ligand backbone, which is partly reduced under acidic conditions.

N-Annulated Perylene Bisimide-Based Double-Cable Polymers with Open-Circuit Voltage Approaching 1.20 V in Single-Component Organic Solar Cells.

In this work, we have introduced single/double-sided N-annulated perylene bisimide (PBI) with deep energy levels into double-cable polymers with poly[1-(5-(4,8-bis(4-chloro-5-(2-ethylhexyl)thiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b']dithiophen-2-yl)thiophen-2-yl)-5,7-bis(2-ethylhexyl)-3-(5-methylthiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c']dithiophene-4,8-dione] (PBDB-T-Cl) as a donor backbone, marking as s-PPNR and as-PPNR, according to the molecular symmetry. Both double-cable polymers displayed a high open-circuit voltage approaching 1.20 V in light of high energy level discrepancy between electron-donating and electron-withdrawing parts, which is the highest open-circuit voltage among double-cable-based single-component organic solar cell (SCOSC) devices. Additionally, the asymmetric polymer displayed improved absorption spectra, thereby promoting crystallization and phase separation. Consequently, the as-PPNR-based SCOSCs achieved a power conversion efficiency of 5.05% along with a higher short-circuit current density and fill factor than their s-PPNR-based counterparts. In this work, we have successfully incorporated N-annulated PBI into double-cable polymers and revealed the important effects on structural symmetry and phase separation of double-cable polymers for higher SCOSC performance.

Three 18-membered macrocyclic diamides with differing donor atoms and backbone substituents

Three 18-membered macrocyclic diamides with differing donor atoms and backbone substituents

Novel wide bandgap benzodithiophene-based polymer donors with electron-withdrawing indolin-2-one side chains for efficient organic solar cells with high open circuit voltage

Two new π-conjugated polymers with donor backbone and π-conjugated indolin-2-one side chains, PBDTTI and PBDTTIF, are designed and synthesized as wide bandgap donors for non-fullerene acceptor-based organic solar cells (OSCs). The monomers containing electron accepting indolin-2-one side chains, (Z)-3-((2,5-dibromothiophen-3-yl) methylene)-1-methylindolin-2-one (M1) and (Z)-3-((2,5-dibromothiophen-3-yl) methylene)-5-fluoro-1-methylindolin-2-one (M2), can be easily synthesized via Knoevenagel condensation between 2,5-dibromothiophene-3-carbaldehyde and 2-oxindole or 5-fluoro-2-oxindole, respectively. Stille coupling polymerization of the electron donating benzodithiophene (BDT)-containing monomer 1,1′-[4,8-bis [5-(2-ethylhexyl)-2-thienyl]benzo [1,2-b:4,5-b′]dithiophene-2,6-diyl]bis [1,1,1-trimethylstannane] and M1 or M2 produced PBDTTI or PBDTTIF, respectively. The strong electron accepting π-conjugated 1-methylindolin-2-one and 5-fluoro-1-methylindolin-2-one side chains can achieve low-lying HOMO energy levels of −5.59 eV for PBDTTI and −5.60 eV for PBDTTIF, which is beneficial for realizing high open circuit voltage (VOC) of the resulting OSCs. On the other hand, since the electron acceptor units are on the side chains, the polymer backbone containing only electron donor units could maintain wide bandgaps of 1.91 eV and 1.89 eV for PBDTTI and PBDTTIF, respectively. When PBDTTI and PBDTTIF were used as donors and a small bandgap non-full acceptor ITIC as an acceptor, the resulting OSCs devices achieved VOC of 0.97 and 1.00 V, short circuit current densities (JSC) of 15.60 and 13.70 mAcm-2, and fill factors (FF) of 0.60 and 0.59, resulting in power conversion efficiencies of 8.00 and 7.70%, respectively.

Promising small molecule Pechmann dye analogue donors with low interfacial charge recombination for photovoltaic application: A DFT study

A series of donor–acceptor–donor (D-A-D) type small molecule (SM) donors containing Pechmann dye analogues (N, S, O) are designed and their geometrical, optoelectronic, charge transport, and photovoltaic properties are investigated using density functional theory (DFT). The structural modification of the donor backbone has been performed via additional sp2-nitrogen heteroatom incorporation in the Pechmann analogue acceptor cores. The N-heteroatom containing SM donors are found to be more air-stable due to having relatively deeper HOMO/LUMO levels than their unsubstituted counterparts. The maximum computed open-circuit voltage (Voc) is 1.53 V for the N-heteroatom substituted O-Pechmann core based donor. The designed donors are expected to harvest photon energy efficiently as their simulated absorption spectra lie in the visible region (575–724 nm). The N-heteroatom incorporation plays a significant role in lowering the charge recombination rate (KCR) and increasing the charge separation rate (KCS) at the SM donor/PC61BM interface. The ratio of interfacial KCS and KCR is found to be improved by 104−1010 times after sp2-nitrogen substitution in the Pechmann analogue cores. The maximum predicted power conversion efficiencies (PCEs) using the Scharber diagram reach up to ∼9% for the S-analogue of the Pechmann dye core based donor. This study sheds light on promising SM donors based on Pechmann dye analogues with low interfacial charge recombination rates and high charge separation rates and also demonstrates the impact of structural modification of Pechmann dye analogue cores on air-stability and overall photovoltaic performance.

Oxidovanadium(IV/V) complexes bound with a ONS donor backbone: The search for therapeutic versatility in one class of compounds

Among the multifarious approaches to treat health challenges such as microbial infections, cancers, and diabetes, metallotherapy is a very significant one. Many transition metal‐based candidates have been previously developed that displayed promising therapeutic interests. Vanadium is one such biologically important transition metal, and in the present work, we have developed potent bioactive vanadium complexes, namely, [{VVO(hpdbal‐smdt)}2μ‐O] (1), [VVO(hpdbal‐smdt)(bha)] (2), [VVO(hpdbal‐smdt)(cat)] (3), [VIVO(hpdbal‐smdt)(phen)] (4), and [VIVO(hpdbal‐smdt)(bipy)] (5), which were synthesized using a ONS donor‐based ligand, H2hpdbal‐smdt (H2L), and [VO(acac)2] alongside secondary ligands, benzohydroxamic acid (bha), catechol (cat), 1,10‐phenanthroline (phen), and 2,2′‐bipyridyl (bipy), respectively. The complexes were mainly characterized using electron paramagnetic resonance (EPR), 1H‐NMR, 13C‐NMR, and infrared (IR) spectroscopy techniques. The ligand was additionally characterized using a single‐crystal X‐ray diffraction (XRD) technique. The compounds were tested for their therapeutic versatility, namely, glucose uptake activity, free radical scavenging activity, and growth inhibitory action towards resilient microbial strains and liver cancer cells. The oxo‐bridged dinuclear vanadium complex (1) showed promising growth inhibitory activity against Pseudomonas aeruginosa bacterial species. Secondary ligand tethered compound (2) displayed notable toxicity against the human liver cancer cells. All complexes induced glucose uptake by the insulin‐resistant cells and exhibited moderate to high antioxidant potential. pH titration and interaction study of these complexes with bovine serum albumin were conducted to investigate solution stability and protein binding properties.

D‐A Polymer with a Donor Backbone ‐ Acceptor‐side‐chain Structure for Organic Solar Cells

AbstractWe report the design, synthesis, and properties of a novel type of donor (D)‐acceptor (A) polymer, poly(3‐(([2,2′:5′,2′′‐terthiophen]‐3‐yl‐5,5“‐diyl)methylene)‐1‐(2‐octyldodecyl)indolin‐2‐one) (PTIBT), with a donor backbone and acceptor side chains (Type II D‐A polymer) as donor for organic solar cells (OSCs) as opposed to the conventional D‐A polymers having both donor and acceptor units on backbone (Type I D‐A polymers). PTIBT having a backbone consisting of thiophene donor units and side chains containing indolin‐2‐one acceptor units was synthesized very conveniently in three steps. This polymer has a high dielectric constant of 7.70, which is beneficial for the exciton diffusion and dissociation in the active blend layer in an OSC. In addition, PTIBT was found to have a low‐lying HOMO energy level of −5.41 eV and a wide band gap of 1.80 eV in comparison to its counterpart Type I D‐A polymer. In organic thin film transistors (OTFTs), PTIBT showed typical p‐type semiconductor performance with hole mobilities of up to 1.81×10−2 cm2 V−1 s−1. When PTIBT and ITIC were used as donor and acceptor to form a blend active layer, the best OSC device showed a JSC of 15.19 mAcm−2, a VOC of 0.66 V, and a fill factor of 0.57, resulting in a power conversion efficiency (PCE) of up to 5.72%.

Synergistic Effects of Polymer Donor Backbone Fluorination and Nitrogenation Translate into Efficient Non-Fullerene Bulk-Heterojunction Polymer Solar Cells.

State-of-the-art non-fullerene bulk-heterojunction (BHJ) polymer solar cells outperform the more extensively studied polymer-fullerene BHJ solar cells in terms of efficiency, thermal-, and photostability. Considering the strong light absorption in the near-infrared region (600-1000 nm) for most of the efficient acceptors, the exploration of high-performing large band gap (LBG) polymer donors with complementary optical absorption ranging from 400 to 700 nm remains critical. In this work, the strategy of concurrently incorporating fluorine (-F) and unsaturated nitrogen (-N) substituents along the polymer backbones is used to develop the LBG polymer donor PB[N][F]. Results show that the F- and N-substituted polymer donor PB[N][F] realizes up to 14.4% efficiency in BHJ photovoltaic devices when paired with a benchmark molecule acceptor Y6, which largely outperforms the analogues PB with an efficiency of only 3.6% and PB[N] with an efficiency of 11.8%. Systematic examinations show that synergistic effects of polymer backbone fluorination and nitrogenation can significantly increase ionization potential values, improve charge transport, and reduce bimolecular recombination and trap-assisted recombination in the PB[N][F]:Y6 BHJ system. Importantly, our study shows that the F- and N-substituted conjugated polymers are promising electron-donor materials for solution-processed non-fullerene BHJ solar cells.

Fluorescent Gene Tagging of Transcriptionally Silent Genes in hiPSCs.

SummaryWe describe a multistep method for endogenous tagging of transcriptionally silent genes in human induced pluripotent stem cells (hiPSCs). A monomeric EGFP (mEGFP) fusion tag and a constitutively expressed mCherry fluorescence selection cassette were delivered in tandem via homology-directed repair to five genes not expressed in hiPSCs but important for cardiomyocyte sarcomere function: TTN, MYL7, MYL2, TNNI1, and ACTN2. CRISPR/Cas9 was used to deliver the selection cassette and subsequently mediate its excision via microhomology-mediated end-joining and non-homologous end-joining. Most excised clones were effectively tagged, and all properly tagged clones expressed the mEGFP fusion protein upon differentiation into cardiomyocytes, allowing live visualization of these cardiac proteins at the sarcomere. This methodology provides a broadly applicable strategy for endogenously tagging transcriptionally silent genes in hiPSCs, potentially enabling their systematic and dynamic study during differentiation and morphogenesis.

Potent drug candidature of an ONS donor tethered copper (II) complex: Anticancer activity, cytotoxicity and spectroscopically approached BSA binding studies.

In our continued efforts to develop metal based therapeutic agents, we have synthesized a novel copper(II) complex, [{Cu(hpdbal-sbdt)}2] (2) tethered with a biocompatible ONS2- donor backbone [H2hpdbal-sbdt] (1) [H2hpdbal-sbdt is a tridentate ligand derived from S-benzyldithiocarbazate (Hsbdt) and 2-hydroxy-5-(phenyldiazenyl)benzaldehyde (Hhpdbal)]. The metal complex (2) was characterized using attenuated total reflection-infrared (ATR-IR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, thermogravimetry and differential scanning calorimetric (TG-DSC) analysis, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and elemental (CHNS) analysis. The antineoplastic ability of copper complex was evaluated in vitro against human cervical cancer (HeLa) cells. MTT assay results showed that the copper complex exhibited significant growth inhibition of HeLa cells with an IC50 value of 4.46 μM and this value was compared with reported standards. Cytotoxicity of the copper complex towards human embryonic kidney cells (HEK-293) was also evaluated. The potentially active copper complex was studied for its solution state stability at a pH range of 3-9. Following this, the interactive behaviour of the bioactive copper complex with a drug transporter protein (BSA) was deciphered through multi-spectrosopic investigations like steady-state fluorescence, three-dimensional fluorescence, deconvoluted-IR and UV-Visible techniques.

Influence of Branched Alkyl Ester-Labeled Side Chains on Specific Chain Arrangement and Charge-Transport Properties of Diketopyrrolopyrrole-Based Conjugated Polymers

A series of diketopyrrolopyrrole (DPP)-based copolymers, with DPP and bithiophene (BT) as the electron-acceptor and donor backbone units, respectively, are synthesized with branched alkyl side chains that are either directly coupled to the N-positions of DPP or separated by an alkyl ester group. The ester moieties in the side chains induce specific cohesive molecular interactions between these side chains, as compared to the alkyl-only side chains with weak van der Waals interactions. Structure analysis of the DPPBT-based copolymers demonstrated that the introduction of a proper alkyl ester spacer to the branched alkyl chains can shorten the π-π stacking distance between the DPPBT backbones down to 3.61 Å and promote the development of two-dimensionally extended domains. DPPBT-based copolymers, including different branched alkyl ester-labeled side chains, are spun-cast on polymer-treated SiO2 dielectrics from dilute chloroform solutions for organic thin-film transistors. A DPPBT-based copolymer with properly engineered side chains (i.e., 2-decyltetradecyl ester-labeled side chains) shows the highest hole mobility of 2.30 cm2 V-1 s-1 and an on/off current ratio of above 106.

Fluorescent nanoaggregates of quinoxaline derivatives for highly efficient and selective sensing of trace picric acid

Two quinoxaline-based luminogens (1a and 1b) appending with triphenylethene rotors with donor–acceptor–donor (D–A–D) backbone are synthesized by a facile synthetic strategy. They show aggregation-enhanced emission (AEE) phenomenon in CH3CN-water mixture. The aggregates of 1a and 1b show highly sensitive and selective fluorescent quenching responses toward picric acid (PA) aqueous solution among a number of nitroaromatic compounds. The quenching constants of KSV were evaluated to be 7.92*105 M−1 and 5.76*105 M−1 for 1a and 1b, respectively. These aggregates are also able to detect PA in vapor phase. The test strip-based sensors can readily detect PA in aqueous media by naked-eye observation instantly at the concentration as low as 5*10−6 M. Our findings demonstrate that 1a and 1b have great potential as excellent sensors for PA. Mechanism studies reveal that synergistic effect of electron transfer, resonance energy transfer and more cavities of nanoaggregates is conducive to good selectivity and high sensitivity of chemosensors (1a and 1b) for detection PA.

Efficient non-doped yellow OLEDs based on thermally activated delayed fluorescence conjugated polymers with an acridine/carbazole donor backbone and triphenyltriazine acceptor pendant

Non-doped OLEDs employing TADF conjugated polymers exhibit excellent electroluminescent performances.

Corrigendum: Conjugated polymer with rigid donor poly(para‐divinylphenylamino) backbone and pendant cyanoacetic acid acceptor for dye sensitized solar cells

A donor backbone [poly(para-divinylphenylamino)]-acceptor (cyanoacetic acid side group) type conjugated polymer (P2) has been synthesized and used as the active material for dye-sensitized solar cells. DFT calculation shows that the insertion of vinyl link in the polymer backbone leads to a planar structure in P2 and changes the excited state significantly. Photoelectrochemical cells based on the DSSC format were fabricated using the polymers as sensitizers. The cell constructed using P2 exhibits a considerably high peak IPCE and J-V response, with an overall power conversion efficiency of 3.67%. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2958–2965

Organometallic assemblies: π-electron delocalization, μ-bridging spacers, flexibility, lipophilic nature, bio-accessibility, bioavailability, intracellular trafficking pathways and antimicrobial assimilation

Supramolecular architectures of triphenylSn(IV)-A(lII)-μ-oxoisopropoxide (organometallic assemblies i.e. Ph3SnOAl(OPri)L and Ph3SnOAl(L)2) were yielded by the reaction of triphenyltin acetate, aluminiumisopropoxide and different ligands (L1 to L5) having different backbones (NOONO and OONO) in presence of xylene. Spectral analysis (IR, 1H NMR, 13C NMR, 27Al NMR, 119Sn NMR and MS) and molecular modeling revealed coordination modes between metals and donor atoms entirely within supramolecular architectures. Ph3SnOAl(OPri)L and Ph3SnOAl(L)2 showed tetra- and penta-coordination of metals center with distorted tetrahedral and distorted trigonal-bipyramidal geometries for Sn(IV) and Al(III) respectively. Organometallic assemblies went through self-organization of atoms through μ-bridging, hydrophobic, hydrophilic and electrostatic effects. Antimicrobial assimilation was dependent on good adsorptive ability, generated by the interaction between microbial and organometallic assemblies. Finally, organometallic assemblies were screened extensively in-vitro against a number of pathogens. The toxicity of metal ion(s) was reduced or eliminated by changing donor backbone of ligands. Computational models and molecular mechanics were employed to reveal architectural features. The donating nature of substituent of ligands affected antimicrobial assimilation. Because of this, desired modifications were done through computational calculations to achieve perfect organometallic assemblies with HOMO for ligands(L1 to L5).

Orbital redistribution in molecular nanostructures mediated by metal-organic bonds.

Dicyanovinyl-quinquethiophene (DCV5T-Me2) is a prototype conjugated oligomer for highly efficient organic solar cells. This class of oligothiophenes are built up by an electron-rich donor (D) backbone and terminal electron-deficient acceptor (A) moieties. Here, we investigated its structural and electronic properties when it is adsorbed on a Au(111) surface using low temperature scanning tunneling microscopy/spectroscopy (STM/STS) and atomic force microscopy (AFM). We find that DCV5T-Me2 self-assembles in extended chains, stabilized by intercalated Au atoms. The effect of metal-ligand hybridization with Au adatoms causes an energetic downshift of the DCV5T-Me2 lowest unoccupied molecular orbital (LUMO) with respect to the uncoordinated molecules on the surface. The asymmetric coordination of a gold atom to only one molecular end group leads to an asymmetric localization of the LUMO and LUMO+1 states at opposite sides. Using model density functional theory (DFT) calculations, we explain such orbital reshaping as a consequence of linear combinations of the original LUMO and LUMO+1 orbitals, mixed by the attachment of a bridging Au adatom. Our study shows that the alignment of molecular orbitals and their distribution within individual molecules can be modified by contacting them to metal atoms in specific sites.

Conjugated polymer with rigid donor poly(para-divinylphenylamino) backbone and pendant cyanoacetic acid acceptor for dye sensitized solar cells

A donor backbone [poly(para-divinylphenylamino)]-acceptor (cyanoacetic acid side group) type conjugated polymer (P2) has been synthesized and used as the active material for dye-sensitized solar cells. DFT calculation shows that the insertion of vinyl link in the polymer backbone leads to a planar structure in P2 and changes the excited state significantly. Photoelectrochemical cells based on the DSSC format were fabricated using the polymers as sensitizers. The cell constructed using P2 exhibits a considerably high peak IPCE and J-V response, with an overall power conversion efficiency of 3.67%. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2958–2965

Intramolecular donor–acceptor copolymers containing side‐chain‐tethered perylenebis(dicarboximide) moieties for panchromatic solar cells

ABSTRACTA series of side‐chain‐tethered copolymers containing the N‐(2‐ethylhexyl)‐N′‐(thiophene‐3‐yl)‐3,4:9,10‐perylenebis(dicarboximide) (thiophene‐PDI) moieties and 4,4‐diethylhexyl‐cyclopenta[2,1‐b:3,4‐b′]dithiophene unit were synthesized via Grignard metathesis polymerizations. With the incorporation of pendent perylenebis(dicarboximide) (PDI) moieties as acceptor side chains and thiophene as the donor backbone, the copolymers exhibited the intramolecular donor–acceptor characteristic and displayed a panchromatic absorption ranging from 290 to 1100 nm and ideal bandgaps of 1.49 to 1.52 eV. Due to the coplanarity of PDI moieties, the charge separation and transfer process were more effective and enhanced after photoexcitation. When increased the weight ratio of PC61BM:polymer to 3, the Jsc could be raised significantly. The value of bandgap decreased slightly, and both Voc and Jsc showed an upward trend with the increase of molar ratio of thiophene‐PDI unit from 50% (the copolymer P11) to 75% (the copolymer P13). The polymer/PC61BM devices have shown a significant improvement from 0.45 to 1.66% with a judicious modulation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1978–1988

Additive-Assisted Control over Phase-Separated Nanostructures by Manipulating Alkylthienyl Position at Donor Backbone for Solution-Processed, Non-Fullerene, All-Small-Molecule Solar Cells

A non-fullerene, all-small-molecule solar cell (NF-SMSC) device uses the blend of a small molecule donor and a small molecule acceptor as the active layer. Aggregation ability is a key factor for this type of solar cell. Herein, we used the alkylthienyl unit to tune the aggregation ability of the diketopyrrolopyrrole (DPP)-based small molecule donors. Replacing two alkoxyl units in BDT-O-DPP with two alkylthienyl units yields BDT-T-DPP, and further introducing another two alkylthienyl units into the backbone produces BDT-T-2T-DPP. With the introduction of alkylthienyl, the backbone becomes twisted. As a result, the ππ-stacking strength, aggregation ability, and crystallite size all obey the sequence of BDT-O-DPP > BDT-T-DPP > BDT-T-2T-DPP. When selected a reported perylene diimide dimer of bis-PDI-T-EG as acceptor, the best NF-SMSC device exhibits a power conversion efficiency of 1.34, 2.01, and 1.62%, respectively, for the BDT-O-DPP, BDT-T-DPP, and BDT-T-2T-DPP based system. The BDT-T-DPP/bis-PDI-T-EG system yields the best efficiency of 2.01% among the three combinations. This is due to the moderate aggregation ability of BDT-T-DPP yields moderate phase size of 30-50 nm, whereas the strong aggregation ability of BDT-O-DPP gives a bigger size of 50-80 nm, and the weak aggregation ability of BDT-T-2T-DPP produces a smaller size of 10-30 nm. The BDT-T-DPP/bis-PDI-T-EG combination exhibits balanced hole/electron mobility of 0.022/0.016 cm(2)/(V s), whereas the BDT-O-DPP/bis-PDI-T-EG and the BDT-T-2T-DPP/bis-PDI-T-EG blend show a hole/electron mobility of 0.0011/0.0057 cm(2)/(V s) and 0.0016/0.11 cm(2)/(V s), respectively.