Synthesis,characterization, and photophysical properties of novel poly(p‐phenylene vinylene) derivatives with conjugated thiophene as side chains

Two novel poly(p‐phenylene vinylene) (PPV) derivatives with conjugated thiophene side chains, P1 and P2, were synthesized by Wittig‐Horner reaction. The resulting polymers were characterized by ¹H‐NMR, FTIR, GPC, DSC, TGA, UV–Vis absorption spectroscopy and cyclic voltammetry (CV). The polymers exhibited good thermal stability and film‐forming ability. The absorption spectra of P1 and P2 showed broader absorption band from 300 to 580 nm compared with poly[(p‐phenylene vinylene)‐alt‐(2‐methoxy‐5‐octyloxy‐p‐phenylene vinylene)] (P3) without conjugated thiophene side chains. Cyclic voltammograms displayed that the bandgap was reduced effectively by attaching conjugated thiophene side chains. This kind of polymer appears to be interesting candidates for solar‐cell applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blue light‐emitting poly(p‐phenylenevinylene) derivative with oxadiazole and carbazole pendant groups

A blue light‐emitting statistical poly(p‐phenylenevinylene) (PPV) copolymer with hole‐transporting carbazole and electron‐transporting oxadiazole pendant groups attached to the kinked m‐terphenyl unit was prepared by Heck coupling between 1,4‐divinylbenzene and dibromides. The latter were synthesized through pyrylium salts. The polymer had optical band gap of 2.89 eV and emission maximum at 446 nm in THF solution and 434 nm in thin film. It showed a pure blue emission with no aggregates or excimers formed even in solid state because of the long and bulky pendant groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3842–3849, 2006     

Synthesis and properties of novel deep red‐emitting copolymers based on a poly(p‐phenylenevinylene) derivative

A series of novel copolymers based on a poly(p‐phenylenevinylene) (PPV) derivative with different content of narrow band‐gap unit 2,1,3‐benzoselenadiazolevinylene (BSeV) was prepared via Stille coupling reaction. The copolymers emit light from deep red to near‐infrared (NIR) depending on BSeV content in the copolymers. The electroluminescence (EL) emission peaked at 752 nm for the copolymer with the content of 30 mol % BSeV is among the longest reported so far for the PPV polymers. The best device performance is observed for the copolymer with 1 mol % BSeV content with external quantum efficiency (QE_ext) of 0.26% and CIE coordinate 0.65, 0.34 (x,y). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4321–4327, 2006     

Synthesis and characterizations of poly(4‐alkylthiazole vinylene)

Two poly(thiazole vinylene) derivatives, poly(4‐hexylthiazole vinylene) (P4HTzV) and poly(4‐nonylthiazole vinylene) (P4NTzV), were synthesized by Pd‐catalyzed Stille coupling method. The polymers are soluble in common organic solvents such as o‐dichlorobenzene and chloroform, and possess good thermal stability. P4HTzV and P4NTzV films exhibit broad absorption bands at 400–720 nm with an optical bandgap of 1.77 eV and 1.74 eV, respectively. The HOMO (the highest occupied molecular orbital) energy levels of P4HTzV and P4NTzV are ?5.11 and ?5.12 eV, respectively, measured by cyclic voltammetry. Preliminary results of the polymer solar cells based on P4HTzV : PC₆₁BM ([6,6]‐phenyl‐C‐61‐butyric acid methyl ester) (1 : 1, w/w) show a power conversion efficiency of 0.21% with an open‐circuit voltage of 0.55 V and a short circuit current density of 1.11 mA cm^?2, under the illumination of AM1.5G, 100 mW cm^?2. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and light‐emitting properties of new poly(p‐phenylenevinylene) derivatives containing oxadiazole moiety

Two new poly(p‐phenylenevinylene) (PPV) derivatives containing the oxadiazole moiety (OXA–PPV1 and OXA–PPV2) were synthesized by the Wittig condensation polymerization reaction and their thermal and light‐emitting properties were investigated. The single‐layer and triple‐layer electroluminescent (EL) devices with configurations of ITO/OXA–PPV1/Al and ITO/OXA–PPV1/OXD/Alq₃/Al were fabricated. They both exhibited blue emission at 460 nm. For comparison, the PPV derivative containing the oxadiazole moiety only in the side chains (OXA–PPV2) was also synthesized. Both single‐layer and triple‐layer EL devices with OXA–PPV2 as the emissive layer emitted green‐light at 560 nm. The turn‐on voltages of the triple‐layer device was 11 V for OXA–PPV1 and 8 V for OXA–PPV2. The triple‐layer EL devices showed much better performance than that of the single‐layer devices. The spectra indicated that energy or electron transfer occurred from the side‐chain oxadiazole to the main‐chain styrene unit. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2424–2428, 2002     

New fluorene–pyrazino[2,3‐g]quinoxaline‐conjugated copolymers: Synthesis,optoelectronic properties,and electroluminescence characteristics

New donor–acceptor conjugated copolymers called poly}2,7‐(9,9′‐dihexylfluorene)‐co‐5,10‐[pyrazino(2,3‐g)quinoxaline]{s or PFPQs [where F represents the 2,7‐(9,9′‐dihexylfluorene) moiety and PQ represents the 5,10‐(pyrazino[2,3‐g]quinoxaline) moiety], synthesized by the palladium‐catalyzed Suzuki coupling reaction, are reported. The PQ contents in the PFPQ copolymers were 0.3, 1, 5, and 50 mol %, and the resulting copolymers were named PFPQ0.3, PFPQ01, PFPQ05, and PFPQ50, respectively. Absorption spectra showed a progressive redshift as the PQ acceptor content increased. The relatively small optical band gap of 2.08 eV for PFPQ50 suggested strong intramolecular charge transfer (ICT) between the F and PQ moieties. The photoluminescence emission peaks of the PFPQ copolymer films also exhibited a large redshift with enhanced PQ contents, ranging from 551 nm for PFPQ0.3 to 592 nm for PFPQ50. However, the PFPQ copolymer based electroluminescence (EL) devices showed poor device performances probably due to the strong confinement of the electrons in the PQ moiety or significant ICT. This problem was resolved with a binary blend of poly[2,7‐(9,9‐dihexylfluorene)] (PF) and PFPQ with a volume ratio of 95/5 (BPQ05). Multiple emission peaks were observed at 421, 444, 480, 516, and 567 nm in the BPQ05‐based EL devices because the low PQ content led to incomplete energy transfer. The Commission Internationale de L'Eclairage 1931 coordinates of the BPQ05‐based EL device were (0.31, 0.32), which were very close to the standard white emission of (0.33, 0.33). Furthermore, the maximum luminescence intensity and luminescence yield were 524 cd/m² and 0.33 cd/A, respectively. This study suggested that a pure white light emission was achieved with the PFPQ copolymers or PF/PFPQ blends through the control of the energy transfer between F and PQ. Such PFPQ copolymers or PF/PFPQ blends would be interesting for electronic and optoelectronic devices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Electroluminescence and photovoltaic properties of poly(p‐phenylene vinylene) derivatives with dendritic pendants

A copolymer of dendronized poly(p‐phenylene vinylene) (PPV), poly{2‐[3′,5′‐bis (2′‐ethylhexyloxy) bnenzyloxy]‐1,4‐phenylene vinylene}‐co‐poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene vinylene] (BE‐co‐MEH–PPV), was synthesized with the Gilch route to improve the electroluminescence and photovoltaic properties of the dendronized PPV homopolymer. The polymer was characterized by ultraviolet–visible absorption spectroscopy, photoluminescence spectroscopy, and electrochemical cyclic voltammetry and compared with the homopolymers poly{2‐[3′, 5′‐bis(2‐ethylhexyloxy) benzyloxy‐1,4‐phenylene vinylene} (BE–PPV) and poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH–PPV). Polymer light‐emitting diodes based on the polymers with the configuration of indium tin oxide (ITO)/poly(3,4‐ethylene dioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/polymer/Ca/Al were fabricated. The electroluminescence efficiency of BE‐co‐MEH–PPV reached 1.64 cd/A, which was much higher than that of BE–PPV (0.68 cd/A) and a little higher than that of MEH–PPV (1.59 cd/A). Photovoltaic properties of the polymer were studied with the device configuration of ITO/PEDOT : PSS/polymer : [6,6J‐phenyl‐C₆₁‐butyric acid methyl ester] (PCBM)/Mg/Al. The power conversion efficiency of the device based on the blend of BE‐co‐MEH–PPV and PCBM with a weight ratio of 1 : 3 reached 1.41% under the illumination of air mass 1.5 (AM1.5) (80 mW/cm²), and this was an improvement in comparison with 0.24% for BE–PPV and 1.32% for MEH–PPV under the same experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Substituent effect on the optoelectronic properties of poly(p‐phenylenevinylene) based conjugated‐nonconjugated copolymers

Two classes of light emitting Poly(p‐phenylenevinylene) (PPV) based conjugated‐nonconjugated copolymers (CNCPs) have been synthesized. The conjugated chromophores containing 2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene (MEHPV) and 2,5‐dimethyl‐1,4‐phenylenevinylene (DMPV) moieties are rigid segments and nonconjugated portion containing hexyl units are flexible in nature. All copolymers were synthesized by well‐known Wittig reaction between the appropriate bisphosphonium salts and the dialdehyde monomers. The resulting polymers were found to be readily soluble in common organic solvents like chloroform, THF and chlorobenzene. The effect of chromophore substituents on the optical and redox properties of the copolymers has been investigated. Color tuning was carried out by varying the molar percentage of the comonomers. The UV‐Vis absorption and PL emission of the copolymers were in the range 314–395 nm and 494–536 nm respectively. All the polymers show good thermal stability. Polymer light‐emitting diodes (PLEDs) were fabricated in ITO/PEDOT:PSS/emitting polymer/cathode configurations of selected polymers using double‐layer, LiF/Al cathode structure. The emission maxima of the polymers were around 499–536 nm, which is a blue‐green part of the color spectrum. The threshold voltages of the EL polymers were in the range of 5.4–6.2 V. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

New anthracene‐containing phenylene‐ or thienylene‐vinylene copolymers: Synthesis,characterization, photophysics,and photovoltaics

Four new conjugated alternating vinylene‐copolymers, PAP6 , PAT , PA , and TAT , incorporating anthracene rings along the backbone were synthesized by Heck coupling. They were very soluble in common organic solvents and absorbed at the range of 300–500 nm with optical band gaps of 2.38–2.47 eV. They behaved in solution as green emitters, with maximum photoluminescence at 455–518 nm. Finally, these soluble copolymers were used as donor material to realize bulk heterojunction solar cell with (6,6)‐C₆₁‐butyric acid methyl ester as the acceptor. More efficient photovoltaic cells were obtained from the copolymer that carried hexyloxy than dodecyloxy side groups. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of poly(1,4‐phenylenevinylene) derivatives containing liquid crystalline oxadiazole groups

Two novel poly(1,4‐phenylenevinylene) (PPV) derivatives containing liquid crystalline oxadiazole side chains were prepared by a dehydrochlorination process. The homopolymer poly(2‐methoxy‐5‐((2‐methoxy‐phenyl)‐5‐hexyloxy‐phenyloxy‐1,3,4‐oxadiazole)‐1,4‐phenylenevinylene) (HO–PE₆) is insoluble in common solvents, whereas the copolymer poly(2‐methoxy‐5‐((2‐methoxy‐phenyl)‐5‐hexyloxy‐phenyloxy‐1,3,4‐oxadiazole))‐(2‐methoxy‐5‐(2′‐ethylhexyloxy))‐1,4‐phenylenevinylene) (CO–PE₆) is soluble in common solvents such as chloroform, THF, and p‐xylene. The molecular structure of CO–PE₆ was confirmed by FTIR, ¹H‐NMR, UV–vis spectroscopy, and polarized light microscopy. CO–PE₆ showed a maximum emission at 556 nm in chloroform and at 564 nm in solid film, when excited at 450 nm. The maximum electroluminescence emission of the device indium–tin oxide (ITO)CO–PE₆/Al is at 555 nm. The turn‐on voltage of LEDs based on CO–PE₆ and MEH–PPV is 6.5 and 8.5 V, respectively. The electron mobility of CO–PE₆ is higher than that of MEH–PPV based on the results of current–voltage and electrochemical behavior of both MEH–PPV and CO–PE₆. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 396–403, 2004     

New low bandgap conjugated polymer derived from 2, 7‐carbazole and 5, 6‐bis(octyloxy)‐4, 7‐di(thiophen‐2‐yl) benzothiadiazole: Synthesis and photovoltaic properties

To develop conjugated polymers with low bandgap, deep HOMO level, and good solubility, a new conjugated alternating copolymer PC‐DODTBT based on N‐9′‐heptadecanyl‐2,7‐carbazole and 5, 6‐bis(octyloxy)‐4,7‐di(thiophen‐2‐yl)benzothiadiazole was synthesized by Suzuki cross‐coupling polymerization reaction. The polymer reveals excellent solubility and thermal stability with the decomposition temperature (5% weight loss) of 327°C. The HOMO level of PC‐DODTBT is ‐5.11 eV, indicating that the polymer has relatively deep HOMO level. The hole mobility of PC‐DODTBT as deduced from SCLC method was found to be 2.03 × 10^?4 cm²/Versus Polymer solar cells (PSCs) based on the blends of PC‐DODTBT and [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) with a weight ratio of 1:2.5 were fabricated. Under AM 1.5 (AM, air mass), 100 mW/cm^?2 illumination, the devices were found to exhibit an open‐circuit voltage (V_oc) of 0.73 V, short‐circuit current density (J_sc) of 5.63 mA/cm^?2, and a power conversion efficiency (PCE) of 1.44%. This photovoltaic performance indicates that the copolymer is promising for polymer solar cells applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and light‐emitting properties of a novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐ (p‐phenylenecyanovinylene)] containing n‐octyloxy side branches

A novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐(p‐phenylenecyanovinylene)] having n‐octyloxy side chains (PPE‐C₈PPE‐PPV) was prepared by polymerization of the monomer DEDB with BCN. Chemical structure of the polymer obtained was confirmed by ¹H NMR, FTIR, and EA. PPE‐C₈PPE‐PPV had a molecular weight enough to fabricate the electroluminescent (EL) device, and showed a good organosolubility, excellent thermal stability, and film‐forming property. In UV absorption and PL spectra in film it showed a maximum at 430 and 543 nm, respectively, which appeared 5 and 41 nm longer wavelengths than that of the solution, respectively. HOMO, LUMO energy levels and band gap were determined to be ?5.70, ?3.29, and 2.41 eV, respectively. Two EL devices with low‐work function cathodes were fabricated with the structures of ITO/PEDOT/PPE‐C₈PPE‐PPV/cathodes (LiF/Al and Mg:Ag/Ag). The both devices exhibited a bright green light emission at 545 nm and the maximum luminescence of 197 cd/cm² (LiF/Al) and 158 cd/cm² (Mg:Ag/Ag). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A polythiophene derivative with dioctyloxyltriphenylamine‐vinylene conjugated side chain: Synthesis,hole mobility,and photovoltaic property

A new polythiophene derivative with dioctyloxyl triphenylamine‐vinylene ( DOTPAV ) conjugated side‐chain, DOTPAV‐PT , was synthesized by the Stille coupling method and characterized by ¹H‐NMR, ¹³C‐NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, UV–vis absorption spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. The polymer DOTPAV‐PT is soluble in common organic solvents and possesses good thermal stability with 5% weight loss temperature of 310°C. The weight‐average molecular weight of DOTPAV‐PT is 8.0 K with a polydispersity index of 1.24. The hole mobility of the polymer determined from space‐charge‐limited current model was 1.25 × 10^?4 cm² V^?1 s^?1. The bulk heterojunction polymer solar cell with the configuration of ITO/PEDOT : PSS/polymer : PCBM (1 : 1)/Ca/Al was fabricated, and the power conversion efficiency of the device was 0.16% under the illumination of AM1.5, 100 mW cm^?2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and photovoltaic properties of polythiophene derivatives with side chains containing C60 end group

A donor–acceptor double‐cable polythiophene derivative ( PT‐F1 ) with side chain containing C₆₀ end group was synthesized, and characterized by infrared, UV‐vis absorption and photoluminescence (PL) spectroscopy, and electrochemical cyclic voltammetry. Cyclic voltammogram of PT‐F1 shows the oxidation peak of the polymer main chains and the reduction peaks of the C₆₀ end groups, indicating that there is no interaction between the polymer main chains and side chain C₆₀ groups on the ground state. The UV‐vis absorption spectrum of PT‐F1 film is red‐shifted in comparison with that of its chloroform solution. The PL spectrum of the polymer main chain was quenched by the C₆₀ pendant on the side chain. Polymer solar cell with the structure of ITO/PEDOT:PSS/ PT‐F1 /Ca/Al was fabricated. The power conversion efficiency of the device based on PT‐F1 reached 0.274% under the illumination of AM 1.5, 100 mW/cm². © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Branched poly(p‐phenylenevinylene): Synthesis,optical and electrochemical properties

A series of poly(p‐phenylene vinylene) (PPV) derivatives with phenylene vinylene side chains (branched PPVs), PPV0, PPV1, PPV2, and PPV3, were synthesized by the Heck coupling reaction and characterized by TGA, absorption spectra, photoluminescence (PL) spectra, and electrochemical cyclic voltammetry. The branched PPVs showed two absorption peaks in the UV–vis region, corresponding to the conjugated side chains (UV absorption) and the main chains (the visible absorption). Especially the absorption spectrum of PPV3 covers a broad wavelength range from 300 to 500 nm. Introducing the electron‐donating alkoxy substituents on the PPV main chains and increasing the content of the alkoxy groups lead to bathochromic shift of both absorption and PL spectra from PPV1 to PPV2 to PPV3. The onset oxidation potential of the branched PPVs is lower by 0.1–0.2 V than that of PPV, indicating that the electron‐donating ability of the branched PPVs enhanced in comparison with that of PPV. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,characterization, and optoelectronic properties of two new polyfluorenes/poly(p‐phenylenevinylene)s copolymers

Two novel copolymers of polyfluorenes/poly(p‐phenylenevinylene)s copolymers with p‐tert‐butyl‐phenylenemethylene groups in the C‐9 position of alternating fluorene unit, poly[1,4‐(2,5‐dibutyloxyl)‐phenyleneviny lene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorene] and poly[1,4‐(2,5‐dioctyloxyl)‐phenylenevinylene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorine], have been synthesized via the Heck polycondensation reaction. The synthesized polymers were characterized by FTIR, NMR, DSC, TGA, UV–vis, and PL spectra. The polymers showed high glass transition temperatures and good thermal stability. A polymer light‐emitting diode with the configuration ITO/PEDOT:PSS/P2/Ca/Al has been fabricated. The device emitted a yellow light with a peak wavelength of 578 nm similar to the PL spectra of the copolymer film. A maximal luminance of 534 cd/m² was obtained at a driving voltage of 24.5 V. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3955–3962, 2006     

Synthesis,electroluminescence, and photovoltaic cells of new vinylene‐copolymers with 4‐(anthracene‐10‐yl)‐2,6‐diphenylpyridine segments

Three new soluble vinylene‐copolymers F , C, and P that contain 4‐(anthracene‐10‐yl)‐2,6‐diphenylpyridine as common segment and fluorene, carbazole, or phenylene, respectively, as alternating segment were prepared by Heck coupling. The glass transition temperature was high for F and C (110 and 117°C), whereas was lower than 25°C for P . The polymers were stable up to ～ 300°C. They emitted blue–green light with maximum located at wavelength of 456–550 nm, which was of the order F < C < P . The photoluminescence quantum efficiency in THF solution was ～ 30% for F and P and only 5% for C . All three copolymers were used as active layers for polymer light emitting diodes (PLEDs) and organic photovoltaic cells. The double PLEDs with configuration of indium‐tin oxide (ITO)/poly(ethylenedioxythiophene (PEDOT) : poly(styrenesulfonate)(PSS)/Copolymer F , C , or P /TPBI(1,3,5‐tris(2‐N‐phenylbenzimidazolyl)benzene)/Ca/Al were fabricated. Copolymer P emitted green light with maximum brightness of 28 cd/m² and a current yield of 0.85 cd/A. Organic photovoltaics with the configuration of ITO/PEDOT : PSS/Copolymer and [6,6]‐phenyl‐C61‐butyric acid methyl ester blend (1 : 1) /Ca/Al were also fabricated. Copolymer P showed the highest power conversion efficiency of 0.034%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and photophysics of a novel conjugated polymer with 1,3,4‐oxadiazole,carbazole, and naphthalene units

A polymer containing 1,3,4‐oxadiazole and carbazole units in the main chain and naphthalene moieties as side groups (P‐OCN) was synthesized by the Wittig reaction of [2,5‐bis(3‐tolylene)1′,3′,4‐oxadiazole]‐9‐(α‐naphthyl)‐carbazole polymer (P‐OCN). The optical properties were investigated with ultraviolet–visible absorption and fluorescence emission spectra. The results showed that the luminescence quantum yield of P‐OCN was 0.673 in chloroform, and it emitted blue and blue‐green light with a band gap of 3.49 eV estimated from the onset absorption. Thermogravimetric analysis and differential scanning calorimetry showed that the polymer exhibited good thermal stability up to 354°C with a glass‐transition temperature higher than 110°C. To investigate the donating and accepting capacities of P‐OCN, the fluorescent quenching technique was used to determinate the interactions between the polymer and the electron donor and electron acceptor. The results showed that the light emission could be quenched by both the electron donor (N,N‐dimethylaniline) and electron acceptor (dimethylterephthalate). Furthermore, the interaction between P‐OCN and fullerene was also studied with fluorescent quenching, and the processes followed the Stern–Volmer equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dioctylfluorene‐thiophene based conjugated copolymers for bulk heterojunction solar cells and enhanced power conversion efficiency via methanol treatment

Sensible design and synthesis of conjugating polymers is important to the development of polymer solar cells (PSCs). In this work, we synthesized and characterized two dioctylfluorene‐thiophene based conjugated copolymers, PFTDPP and PFTpBT, having different acceptor groups on the backbone. The photovoltaic properties of the copolymers blended with 6,6‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) as an electron acceptor were obtained. The PSC based on a conventional device configuration ITO/PEDOT:PSS/ Polymer:PC₆₁BM/LiF/Al showed power conversion efficiencies (PCEs) of 2.42% and 3.02% for PFTDPP and PFTpBT, respectively. Methanol treatment was introduced to further optimize device performance, and the solvent treatment gave a dramatic increase in PCE. The best PCEs could reach 4.25% and 4.20% after methanol treatment under AM 1.5G illumination with an intensity of 100 mW cm^?2 from a solar simulator. © 2015 Society of Chemical Industry     

Synthesis and properties of alkyl‐substituted poly(1,4‐phenylenevinylene) derivatives

The luminescent poly(2‐dodecyl‐5‐methyl‐1,4‐phenylenevinylene) was synthesized with a new synthetic route. The structure and properties of the polymers were characterized by IR, UV‐vis, luminescent spectra, GPC, and both thermal and elemental analysis. The glass‐transition temperature increases and the photoluminescent relative quantum yield decreases with the increase of the conjugation extent of the polymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1299–1304, 2001