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Two new C60-based n-type materials, EGMC-OH and EGMC-COOH, functionalized with hydrophilic triethylene glycol groups (TEGs), have been synthesized and employed in conventional polymer solar cells. With the assistance of the TEG-based surfactant, EGMC-OH and EGMC-COOH can be dissolved in highly polar solvents to implement the polar/nonpolar orthogonal solvent strategy, forming an electron modification layer (EML) without eroding the underlying active layer. Multilayer conventional solar cells on the basis of ITO/PEDOT:PSS/P3HT:PC61BM/EML/Ca/Al configuration with the insertion of the EGMC-OH and EGMC-COOH EML between the active layer and the electrode have thus been successfully realized by cost-effective solution processing techniques. Moreover, the electron conductivity of the EML can be improved by incorporating alkali carbonates into the EGMC-COOH EML. Compared to the pristine device with a PCE of 3.61%, the devices modified by the Li2CO3-doped EGMC-COOH EML achieved a highest PCE of 4.29%. Furthermore, we demonstrated that the formation of the EGMC-COOH EML can be utilized as a general approach in the fabrication of highly efficient multilayer conventional devices. With the incorporation of the EGMC-COOH doped with 40 wt % Li2CO3, the PCDCTBT-C8:PC71BM-based device exhibited a superior PCE of 4.51%, which outperformed the corresponding nonmodified device with a PCE of 3.63%.

A pentacyclic benzodipyrrolothiophene (BDPT) unit, in which two outer thiophene rings are covalently fastened with the central phenylene ring by nitrogen bridges, was synthesized. The two pyrrole units embedded in BDPT were constructed by using one-pot palladium-catalyzed amination. The coplanar stannylated Sn-BDPT building block was copolymerized with electron-deficient thieno[3,4-c]pyrrole-4,6-dione (TPD), benzothiadiazole (BT), and dithienyl-diketopyrrolopyrrole (DPP) acceptors by Stille polymerization. The bridging nitrogen atoms make the BDPT motif highly electron-abundant and structurally coplanar, which allows for tailoring the optical and electronic properties of the resultant polymers. Strong photoinduced charge-transfer with significant band-broadening in the solid state and relatively higher oxidation potential are characteristic of the BDPT-based polymers. Poly(benzodipyrrolothiophene-alt-benzothiadiazole) (PBDPTBT) achieved the highest field-effect hole mobility of up to 0.02 cm(2) V(-1) s(-1). The photovoltaic device using the PBDPTBT/PC(71)BM blend (1:3, w/w) exhibited a V(oc) of 0.6 V, a J(sc) of 10.34 mA cm(-2), and a FF of 50%, leading to a decent PCE of 3.08%. Encouragingly, the device incorporating poly(benzodipyrrolothiophene-alt-thienopyrrolodione) (PBDPTTPD)/PC(71)BM (1:3, w/w) composite delivered a highest PCE of 3.72%. The enhanced performance arises from the lower-lying HOMO value of PBDPTTPD to yield a higher V(oc) of 0.72 V.

We have developed a ladder- type dithienocyclopentathienoA b)thiophene (DTCTT) hexacyclic unit in which the central thienoAb)thio- phene ring was covalently fastened to two adjacent thiophene rings through carbon bridges, thereby forming two connected cyclopentadithiophene (CPDT) units in a hexacyclic coplanar structure. This stannylated Sn-DTCTT building block was copolymerized with three electron-deficient acceptors, di- bromo-thienoAc)pyrrole-4,6-dione (TPD), dibromo-benzothiadiazole (BT), and dibromo-phenanthrenequi- noxaline (PQX), by Stille polymeri- zation, thereby furnishing a new class of alternating donor-acceptor copoly- mers: PDTCTTTPD, PDTCTTBT, and PDTCTTPQX, respectively. Field- effect transistors based on PDTCTTPQX and PDTCTTBT yield- ed high hole mobilities of 0.017 and 0.053 cm 2 V 1 s 1 , respectively, which are among the highest performances among amorphous donor-acceptor co- polymers. A bulk heterojunction solar cell that incorporated PDTCTTTPD with the lower-lying HOMO energy level delivered a higher Voc value of 0.72 V and a power conversion efficien- cy (PCE) value of 2.59 %.

A flexible solar device showing exceptional air and mechanical stability is produced by simultaneously optimizing molecular structure, active layer morphology, and interface characteristics. The PFDCTBT-C8-based devices with inverted architecture exhibited excellent power conversion efficiencies of 7.0% and 6.0% on glass and flexible substrates, respectively.

Nitrogen-bridged donor–acceptor multifused dithienopyrrolobenzothiadiazole (DTPBT) and dibenzothiadiazolopyrrolothiophene (DBTPT) were successfully synthesized by intramolecular Cadogan annulation. The electron-deficient benzothiadiazole unit in DTPBT can be converted to benzoselenadiazole and quinoxaline moieties through reduction/cyclization to generate dithienopyrrolobenzoselenadiazole (DTPBSe) and dithienopyrroloquinoxaline (DTPQX), respectively. The nitrogen atoms function as the bridges for covalent planarization to induce intermolecular interaction and intramolecular charge transfer.

A poly(3-hexylthiophene) (P3HT)-based inverted solar cell using indene-C60 bis-adduct (ICBA) as the acceptor achieved a high open-circuit voltage of 0.82 V due to ICBA’s higher-lying lowest unoccupied molecular orbital level, leading to an exceptional power-conversion efficiency (PCE) of 4.8%. By incorporating a cross-linked fullerene interlayer, C-PCBSD, to further modulate the interface characteristics, the ICBA:P3HT-based inverted device exhibited an improved short-circuit current and fill factor, yielding a record high PCE of 6.2%.

We report here two novel 2,7-fluorene- and 2,7-carbazole-based conjugated polymers PFDCTBT and PCDCTBT containing ladder-type heptacyclic structures with forced planarity. PCDTBT shows excellent solubility, low band gap and high hole mobility, leading to a power conversion efficiency of 3.7%.

phenylenevinylene)s L4. Fluorene-Based Conjugated Polymers L4.1. Fluorene-Based Copolymers ContainingElectron-Rich MoietiesM4.2. Fluorene-Based Copolymers ContainingElectron-Deficient MoietiesN4.3. Fluorene-Based Copolymers ContainingPhosphorescent ComplexesQ5. Carbazole-Based Conjugated Polymers R5.1. Poly(2,7-carbazole)-Based Polymers R5.2. Indolo[3,2

A major breakthrough in the area of organic electro-optic (EO) materials has been recently achieved. To go beyond the oriented gas model limit for organic EO materials, new approaches of using nanoscale architecture control and supramolecular self-assembly have been proved as a very effective method to create a new paradigm for materials with very exciting properties. High-performance EO polymers were demonstrated by a facile and reliable Diels-Alder "click" reaction for postfunctionalization and lattice hardening to improve EO activity and thermal stability. This type of "click" chemistry paves the way to systematically study the relationship among EO activity, chromophore shape, and number density of the chromophores. Reversible supramolecular interactions were also introduced to a new generation of EO dendrimers and polymers to create self-assembled nano-objects, overcome strong intermolecular electrostatic interaction, and improve their poling efficiency and stability. These self-organized EO materials were used as hosts in a binary chromophore system to further improve chromophore number density and r 33 value. With these novel approaches, we succeeded in enlarging the full potential of organic NLO materials by a factor of 3~5 and developing a variety of nano-structured organic EO materials with ultrahigh r 33 values (>300 pm/V at the wavelengths of 1310 and 1550 nm, more than 10 times that of LiNbO 3 ) and excellent auxiliary property, such as thermal stability and optical transparency. The success of these material developments has inspired the exploration of new device concepts to take full advantage of organic EO materials with ultrahigh r 33 values.

[reaction: see text] A facile synthetic route has been developed to convert an electron-rich, sterically hindered dialkylaminodienone into a conjugated dialkylaminotrienal with good yield. The derived dialkylaminotetraene-type nonlinear optical chromophores possess an all-trans conformation and can be functionalized with fluoro-dendron to provide proper shape modification for poling. Polymers doped with two examples of these chromophores in high concentrations have been poled to afford ultra-large electrooptic coefficients (r(33)) of 208 and 262 pm/V, respectively, at the measuring wavelength of 1.31 mum.

Heteroaromatics-containing polymers comprise a huge class of materials that have received considerable attention due to their interesting electrical, electrochemical, and optical properties. In this review, the recent advances on the use of organometallic cross-coupling reactions for the synthesis of heteroaromatic conjugated polymers for the optoelectronic interests and applications are summarised.

Background The diagnosis of oral cavity cancers and treatments/disease related distress from the oral–facial areas may influence patients’ quality of life (QOL). The purposes of this study were to (1) examine the changes of symptoms (physical distress), psychological distress (depression and anxiety) and QOL during the first 12 months of being diagnosed as oral cavity cancer, (2) identify factors related to overall QOL, and (3) identify QOL sub-patterns in newly diagnosed oral cavity cancer patients in Taiwan. Materials and methods A 12-month prospective longitudinal study was conducted to assess the changes of symptom, psychological distress and QOL. Subjects were recruited from three medical centers in Northern Taiwan and were assessed on 6 time points (days before operation, 1, 2, 3, 6 12 months post surgery/T1–T6, respectively). The psychometrically validated Chinese version instruments were used, including (1) Symptom Severity Scale (SSS), (2) Hospital Anxiety and Depression Scale (HADS), (3) University of Washington Quality of Life (UW-QOL), and (4) Background Information Form. In addition to the descriptive statistics, the Generalized Estimating Equations (GEE) was applied to identify the overall QOL related factors. The latent class growth modeling was used to identify the potential QOL sub-patterns. Data were collected after Institute Review Board (IRB) approval and patients’ consents. Results A total of 150 eligible subjects completed the 12 months assessments. Overall, patients reported moderate levels of QOL with the worst QOL during the first three months post-surgery (T2–T4). However, some delayed problems were also reported, including dry mouth, swallowing problem, chewing dysfunction and employment concern. Patients having reconstruction surgery, more advanced cancer stage, higher levels of depression and symptom severity, without job, and having lower education level were found to have lower levels of QOL across the time. QOL sub-patterns were also identified. Conclusion Results of the study provide the evidence-based information to health care professionals to better help oral cavity cancer patients with timely interventions. Future studies should also test the effects of these interventions on improving patients’ QOL.

A series of silylene-spaced alternating [(donor-SiMe2)(n=1-3)-(acceptor-SiMe2)] copolymers 4-6 was synthesized by rhodium-catalyzed hydrosilylation of bisalkynes with bissilyl hydrides. Monomeric reference compounds 7-10 with similar chromophore components were prepared for comparison. The ratio of donor to acceptor groups is well-controlled by the precise regiochemistry and nature of the repeat units. The silylene moieties serve as insulating spacers between chromophores. The polymers exhibit light-harvesting abilities, for which the intensity of the emission enhanced with larger donor-to-acceptor ratios. No emission originating from the donors was observed in fluorescence spectra, illustrating that intrachain energy transfer is highly efficient along the polymer chain.

Bulk heterojunction (BHJ) polymer solar cells (PSCs) on the basis of polymer:fullerene blends have delivered numerous impressive results in the last decade and thus have drawn much attention of the scientific and industrial communities. However, BHJ PSCs often suffer from several intrinsic problems, such as the low open-circuit voltage (Voc), energetically-unfavorable and chemically-incompatible interfaces, and morphological phase separation of the polymer:fullerene blend driven by thermal treatment, hindering further advancement. In this review, we summarize the recent progress on applications of fullerene-based materials in the BHJ PSCs. Bis-adduct fullerenes possessing high-lying LUMO energy levels can substitute for mono-substituted fullerenes and higher Voc values can thus be achieved. Incorporation of an n-type fullerene interlayer between inorganic and organic active layers in either inverted or conventional PSCs can help in minimization of charge recombination losses at the interface and improvement of charge transfer from the active layer to the inorganic layer, thus resulting in superior PCEs. The optimal active-layer morphology can be maintained through several approaches, such as in situ polymerization of cross-linkable fullerenes, suppression of large-scale PC61BM aggregation by a polyethylene glycol-functionalized fullerene, supramolecular pentafluorophenyl-fullerene stabilization, and light-induced oligomerization of fullerenes. The morphological phase separation of the active-layer materials can thus be minimized. The research of employing fullerene materials will continue playing a critical role in BHJ PSCs. With further investigation and advancement in this field, it is expected that the ultimate goal of commercialization can be realized.

We have developed a new ladder-type conjugated polymer PBDCPDT–FBT and a robust interconnecting layer (ICL) integrating a hole-collecting m-PEDOT:PSS layer with an electron-collecting ZnO layer. The inverted device using PBDCPDT–FBT exhibited a high power conversion efficiency (PCE) of 5.76% with a Voc of 0.81 V, a Jsc of 12.82 mA cm−2, and a FF of 55.5%. The inverted tandem device incorporating the PBDCPDT–FBT and ICL achieves a Voc of 1.62 V leading to a PCE of 7.08%.

A new design for constructing two-dimensional conjugated copolymers with the D1–A(D2) repeating pattern (A: acceptor, D1: donor 1, D2: donor 2; molecules enclosed in parentheses are pendant groups.), is proposed. D1 and A are employed to construct the linear main-conjugated polymer chain and D2 is situated at the conjugated side chains connected to A. We designed and synthesized a series of D1–A(D2)-type copolymers, in which D1 = diindeno[1,2-b:2′,1′-d]-thiophene (DIDT) or fluorene (F), A(D2) = bis-[4-(dioctylamino)-phenyl] quinoxaline (DOAQX) or bis-[4-(dioctylamino)-phenyl] thieno[3,4-b]pyrazine (DOATP), and D2 = N,N-dioctylanilines. The resultant copolymers, PDIDTDOAQX, PFDOAQX, PDIDTDOATP and PFDOATP, possess at least two strong ICT absorptions, thus resulting in better light harvesting. Their optical and electronic properties were thoroughly investigated experimentally and computationally. Bulk heterojunction photovoltaic cells on the basis of ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al configuration were fabricated and characterized. The photovoltaic performances of the devices incorporating these polymers follow the sequence: PDIDTDOAQX > PFDOAQX > PDIDTDOATP > PFDOATP, which is in good agreement with the magnitude of their hole-mobilities.

We report a novel diindenothieno[2,3-b]thiophene ladder-type hexacyclic arene for constructing a donor-acceptor copolymer PDITTDTBT. A device based on PDITTDTBT:PC(71)BM exhibited a high V(oc) of 0.92 V with an impressive PCE of 5.8%, while a PDITTDTBT:DMPCBA-based device showed an extra high V(oc) of 1.14 V.

Silylene-spaced donor-acceptor divinylarene copolymers are synthesized by hydrosilylation of bisalkynes 7 with bisvinylsilanes 3; efficient intrachain energy transfer between donor-acceptor chromophores is observed.

A continuous roll-to-roll compatible blade-coating method for multi-layers of general organic semiconductors is developed. Dissolution of the underlying film during coating is prevented by simultaneously applying heating from the bottom and gentle hot wind from the top. The solvent is immediately expelled and reflow inhibited. This method succeeds for polymers and small molecules. Uniformity is within 10% for 5 cm by 5 cm area with a mean value of tens of nanometers for both organic light-emitting diode (OLED) and solar cell structure with little material waste. For phosphorescent OLED 25 cd/A is achieved for green, 15 cd/A for orange, and 8 cd/A for blue. For fluorescent OLED 4.3 cd/A is achieved for blue, 9 cd/A for orange, and 6.9 cd/A for white. For OLED with 2 cm by 3 cm active area, the luminance variation is within 10%. Power conversion efficiency of 4.1% is achieved for polymer solar cell, similar to spin coating using the same materials. Very-low-cost and high-throughput fabrication of efficient ...

A series of phenyltetraene-based nonlinear optical (NLO) chromophores 1a–c with the same donor and acceptor groups, but different tetraene bridges that are partly connected by various sizes of aliphatic rings, have been synthesized and systematically investigated. The interposed conjugated tetraene segments in three chromophores studied are based on isophorone, (1S)-(−)-verbenone, and 3,4,4-trimethyl-2-cyclopentenone, respectively. This kind of structural alteration has significant effect on the intrinsic electronic structures and physical properties of these highly polarizable chromophores as revealed by a variety of characterization techniques. The introduction of the verbenone- and trimethylcyclopentenone-based tetraene bridges could significantly improve the glass-forming ability of chromophores 1b and 1c in comparison with the highly crystalline characteristics of isophorone-based chromophores 1a. More importantly, chromophores 1a–c exhibited distinct optical features in absorption band shape, solvatochromic behavior, as well as energy band gap from the UV-vis-NIR absorption measurements. Quantum mechanical calculations using density functional theory (DFT) were also used to evaluate second-order NLO properties of these chromophores. The electro-optic (EO) coefficients of 1a–c in poled polymers with the 10 wt% chromophore content showed an apparent decrease from 78 pm V−1 for 1a to 42 pm V−1 for 1c. This decrease is attributed to the gradual decrease of the molecular hyperpolarizability (β) of the chromophores which is associated with the progressive cyanine-like electronic structure from the isophorone-based 1a to the cyclopentenone-based 1cchromophore.

One of the most challenging tasks in fabricating multilayer polymer light-emitting diodes (PLEDs) by solution processes is to avoid the interfacial mixing between different layers because most of the commercially available emissive and charge-transporting materials are soluble in common organic solvents. To overcome this difficulty, extensive efforts have been invested in developing novel crosslinkable hole-transporting materials (HTMs). After thermo- or photo-crosslinking, all these crosslinked HTMs possess very good solvent resistance which greatly facilitates the subsequent processing of the emitting layer. By taking advantage of these HTMs, high efficiency red–green–blue (RGB)-emitting PLEDs, as well as white- and quantum dot based PLEDs, have been realized. This article provides a brief overview of the recent development of crosslinkable HTMs and their unique advantages in enhancing the performance of LEDs.

Second hole-transport layer (HTL) with perfect solvent-resistance is formed via spin-coating then thermally crosslinking on top of a pre-crosslinked HTL or p-type conducting polymer layer. By judiciously choosing the energy levels of the hole-transport moieties, cascade hole-injection can be realized for a light-emitting layer with phosphorescent blue emitters (and white thereafter).