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Two wide-bandgap (WBG) conjugated polymers (PBPD-p and PBPD-m) based on phenyl-substituted benzodithiophene (BDT) with the different substitution position of the alkyl side chain and benzodithiophene-4,8-dione (BDD) units are designed and synthesized to investigate the influence of alkyl substitution position on the photovoltaic performance of polymers in polymer solar cells (PSCs). The thermogravimetric analysis, absorption spectroscopy, molecular energy level, X-ray diffraction, charge transport and photovoltaic performance of the polymers are systematically studied. Compared with PBPD-p, PBPD-m exhibits a slight blue-shift but a deeper highest occupied molecular orbital (HOMO) energy level, a tighter alkyl chain packing and a higher hole mobility. The PBPD-m-based PSCs blended with acceptor IT-4F shows a higher power conversion efficiency (PCE) of 11.95% with a high open-circuit voltage (Voc ) of 0.88 V, a short-circuit current density (Jsc ) of 19.76 mA cm-2 and a fill factor (FF) of 68.7% when compared with the PCE of 6.97% with a Voc of 0.81 V, a Jsc of 15.97 mA cm-2 and an FF of 53.9% for PBPD-p. These results suggest that it is a feasible and effective strategy to optimize photovoltaic properties of WBG polymers by changing the substitution position of alkyl side chain in PSCs.

Nonfullerene polymer solar cells (PSCs) are developed based on a fluorinated thienyl-based wide-bandgap (WBG) polymer PBBF as the electron donor and nonfullerene small molecule IDIC as the electron acceptor. PBBF exhibits a strong absorption in the range of 300-605 nm with a wide optical bandgap of 2.05 eV, which is complementary with that of IDIC. Meanwhile, it possesses a deeper highest occupied molecular orbital energy level of -5.52 eV and a higher hole mobility of 7.3 × 10-4 cm2 V-1 s-1 compared to the nonfluorinated polymer PBDTT. The PSCs based on PBBF:IDIC without extra treatment show a power conversion efficiency (PCE) of 8.5% with a V oc of 0.95 V, a J sc of 15.3 mA cm-2 , and an FF of 58.8%, which is much higher than that of the devices based on PBDTT:IDIC (a PCE of 5.3% with a V oc of 0.88 V, a J sc of 13.7 mA cm-2 , and an FF of 43.9%). These results indicate that PBBF is a promising WBG polymer donor material for the photovoltaic applications in nonfullerene PSCs.

Two near-infrared (NIR) absorbing metallopolyynes of platinum (P1 and P2) functionalized with a weakly electron-donating fluorene unit and two strong electron acceptors (viz. benzo[1,2-c: 4,5-c'] bis([1,2,5] thiadiazole) and [1,2,5] thiadiazolo[3,4-i] dibenzo[a, c] phenazine) were synthesized and applied for NIR photovoltaic applications. With these designed weak donor-strong acceptor electronic traits, these metallopolymers possess narrow bandgaps of 1.54 and 1.65 eV and a low HOMO level of about 5.50 eV, thus inducing a power conversion efficiency up to 1% for bulk heterojunction solar cells at the NIR wavelength.

Two solution-processable metallopolyynes of platinum functionalized with the electron-deficient 4H-cyclopenta[2,1-b:3,4-b']dithiophen-4-one spacer and their model molecular complexes were synthesized and developed for the applications of polymer solar cells. These metallated polymers possess extremely low bandgaps of 1.44-1.53 eV which extend toward the near-infrared (NIR) range of the solar spectrum, and represent the lowest optical bandgap yet reported for platinum(II) metallopolyynes to date. The structural flexibility, processibility, and good photovoltaic performance make cyclopentadithiophenone-containing polymers prominent candidates for NIR photovoltaic applications.

This review article surveys the electronic and photophysical properties of conjugated organometallic polymers built upon the title compound and its related derivatives focussing primarily on systems investigated in our laboratories. The general structure of the polymers is (trans-bis(para-ethynylbenzene)bis(phosphine)platinum(II)-G)(n) where G is a conjugated group such as thiophene, fluorene, carbazole, substituted silole, quinone derivative, and metalloporphyrin residue, or a non-conjugated main-group moiety. Systems based on substituted phenylene units and other related fused rings are also discussed. The phosphine ligands are generally triethyl- or tri-n-butylphosphine groups. These trans-platinum(II) polymers and the corresponding model compounds are compared to the corresponding ortho-derivatives in the quinone series, and the newly prepared paracyclophane-containing polymers. For the porphyrin series, a comparison of fully conjugated oligomers exhibiting the general structure (trans-bis(para-ethynyl(zinc(porphyrin)))bis(phosphine)platinum(II))(n) (i.e., the C(6) H(4) group is absent from the main chain) will be made. This contribution also includes a description of the properties of the mononuclear chromophore itself, properties that define those of the polymers. Potential applications with regard to electronic and optical devices will be highlighted. These soluble and stable materials feature both the processing advantages of polymers and the functionality provided by the presence of metal centers. These multifunctional organometallic polyyne polymers exhibit convenient structural variability as well as optical and electronic properties, which renders them important for use in different research domains as chemical sensors and sensor protectors, as converters for light/electricity signals, and as patternable precursors to magnetic metal alloy nanoparticles.

The synthesis and thermal, redox and photoluminescence properties of a soluble donor-acceptor polyplatinayne with the electron-accepting silole ring and its model compound are described. The polymer has an optical band gap of 2.10 eV which is much lower than that of thienyl- or silyl-bridged congeners. The incorporation of electron-accepting silole unit in the metallopolymer main chain creates a new π-conjugated system that features unique donor-acceptor characteristics.

In view of the strong electron-with-drawing nature of the cyano substituent, a blue donor/acceptor-type organometallic polymer (trans-[-Pt(PBu 3 ) 2 =C≡C-R-C≡C-] n (R = 9-dicyanomethylenefluorene-2,7-diyl)) was prepared in good yield by CuI-catalyzed polymerization involving the dehydrohalogenating coupling of trans-[-Pt(PBu 3 ) 2 Cl 2 ] and H-C≡C-R-C≡C-H. The thermal, redox and photoconducting properties of the polymer are reported. Electronic absorption studies indicate that it has a bandgap of 1.58 eV which is the lowest among any of the metal polyyne polymers reported in the literature. The derivatization of the polymer backbone with electron deficient dicyano-substituted electron acceptor in the side chain is found to be effective to tune the bandgap of this class of materials while maintaining their solubility and processability.

By virtue of the electron-donating and electron-withdrawing properties of the thiazole ring, a new soluble rigid-rod organometallic polymer containing electron-donating and electron-withdrawing trans-[-Pt-(PBu3)2-C≡C—R—C≡C—]n (R = bithiazolediyl) groups is prepared by CuI-catalyzed dehydrohalogenation. The thermal properties and the optical absorption and photoluminescence spectra of the polymer are reported. The polymer is luminescent with a singlet emission peak at 539 nm and photoconducting in a single-layer sandwich structure photocell. The optical gap of the polymer is reduced compared to that for the oligothienyl analogue.

Two solution-processable platinum-acetylide polymers functionalized with the electron-deficient thiazolothiazole spacer are synthesized and show absorption features spanning from 320 to 600 nm and optical bandgaps of 2.15 and 2.05 eV. The spin-coated polymer thin films of both materials exhibit p-channel field-effect charge transport characteristics with impressive peak field-effect charge-carrier mobilities of (2.1-2.8) × 10(-2) cm(2) V(-1) s(-1) and on/off ratios of (0.8-1.0) × 10(5) for the holes. The high hole mobility value reported for one of the polymers is among the highest reported for metallopolyynes to date. It is also shown that the hole mobility can be notably increased by extending the conjugation length of the chain from the monothienyl to the bithienyl segment on each side of the thiazolothiazole ring.

Two solution-processable metallopolyynes of platinum functionalized with the electron-deficient 4H-cyclopenta[2,1-b:3,4-b']dithiophen-4-one spacer and their model molecular complexes were synthesized and developed for the applications of polymer solar cells. These metallated polymers possess extremely low bandgaps of 1.44-1.53 eV which extend toward the near-infrared (NIR) range of the solar spectrum, and represent the lowest optical bandgap yet reported for platinum(II) metallopolyynes to date. The structural flexibility, processibility, and good photovoltaic performance make cyclopentadithiophenone-containing polymers prominent candidates for NIR photovoltaic applications.

This review article surveys the electronic and photophysical properties of conjugated organometallic polymers built upon the title compound and its related derivatives focussing primarily on systems investigated in our laboratories. The general structure of the polymers is (trans-bis(para-ethynylbenzene)bis(phosphine)platinum(II)-G)(n) where G is a conjugated group such as thiophene, fluorene, carbazole, substituted silole, quinone derivative, and metalloporphyrin residue, or a non-conjugated main-group moiety. Systems based on substituted phenylene units and other related fused rings are also discussed. The phosphine ligands are generally triethyl- or tri-n-butylphosphine groups. These trans-platinum(II) polymers and the corresponding model compounds are compared to the corresponding ortho-derivatives in the quinone series, and the newly prepared paracyclophane-containing polymers. For the porphyrin series, a comparison of fully conjugated oligomers exhibiting the general structure (trans-bis(para-ethynyl(zinc(porphyrin)))bis(phosphine)platinum(II))(n) (i.e., the C(6) H(4) group is absent from the main chain) will be made. This contribution also includes a description of the properties of the mononuclear chromophore itself, properties that define those of the polymers. Potential applications with regard to electronic and optical devices will be highlighted. These soluble and stable materials feature both the processing advantages of polymers and the functionality provided by the presence of metal centers. These multifunctional organometallic polyyne polymers exhibit convenient structural variability as well as optical and electronic properties, which renders them important for use in different research domains as chemical sensors and sensor protectors, as converters for light/electricity signals, and as patternable precursors to magnetic metal alloy nanoparticles.