-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-

https://ir.nctu.edu.tw:443/bitstream/11536/6508/1/000271856900020.pdf

Synthesis of Conjugated Polymers for Organic Solar Cell Applications

Heterojunctions in Solar Cells. Lessons Learned from the Benchmark Poly(3-hexylthiophene):[6,6]-Phenyl‐C61-butyric Acid Methyl Ester System Minh Trung Dang,† Lionel Hirsch,‡ Guillaume Wantz,‡ and James D. Wuest*,† †Deṕartement de Chimie, Universite ́ de Montreál, Pavillon J.-Armand Bombardier, 2900 boulevard Édouard-Montpetit, Montreál, Queb́ec H3T 1J4, Canada ‡Laboratoire de l'Inteǵration du Mateŕiau au System̀e, Universite ́ de Bordeaux, UMR CNRS 5218, École Nationale Supeŕieure de Chimie, Biologie et Physique, 16 Avenue Pey Berland, 33607 Pessac Cedex, France

Controlling the Morphology and Performance of Bulk Heterojunctions in Solar Cells. Lessons Learned from the Benchmark Poly(3-hexylthiophene):[6,6]-Phenyl-C61-butyric Acid Methyl Ester System

The power conversion efficiencies of bulk heterojunction (BHJ) solar cells can be increased from 5 to 6.5% by incorporating an ultrathin conjugated polyelectrolyte (CPE) layer between the active layer and the metal cathode. Poly[N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) were chosen for the photoactive layer. CPEs with cationic polythiophenes, in both homopolymer and block copolymer configurations, were used to improve the electronic characteristics. The significant improvement in device performance and the simplicity of fabrication by solution processing suggest a promising and practical pathway for improving polymer solar cells with high efficiencies.

Improved high-efficiency organic solar cells via incorporation of a conjugated polyelectrolyte interlayer.

We have developed a kind of novel fused-ring small molecular acceptor, whose planar conformation can be locked by intramolecular noncovalent interaction. The formation of planar supramolecular fused-ring structure by conformation locking can effectively broaden its absorption spectrum, enhance the electron mobility, and reduce the nonradiative energy loss. Polymer solar cells (PSCs) based on this acceptor afforded a power conversion efficiency (PCE) of 9.6%. In contrast, PSCs based on similar acceptor, which cannot form a flat conformation, only gave a PCE of 2.3%. Such design strategy, which can make the synthesis of small molecular acceptor much easier, will be promising in developing a new acceptor for high efficiency polymer solar cells.

Exploiting Noncovalently Conformational Locking as a Design Strategy for High Performance Fused-Ring Electron Acceptor Used in Polymer Solar Cells.

Water/alcohol-soluble conjugated polymers (WSCPs) and small molecules (WSCSs) are materials that can be processed from water or other polar solvents. They provide good opportunities to fabricate multilayer organic optoelectronic devices without interface mixing by solution processing, and exhibit a promising interface modification ability for metal or metal oxide electrodes to greatly enhance the device performance of solar cells. Moreover, owing to their intriguing processability, WSCPs and WSCSs have great potential for applying environmentally friendly processing technologies to fabricate solar cells. In this review, the authors give an overview of recent developments in WSCPs and WSCSs, including their molecular design, material synthesis, functional principles and application as interface modification layers and photoactive components in emerging photovoltaic technologies such as organic/polymer solar cells, organic–inorganic hybrid solar cells and dye-sensitised solar cells.

Recent advances in water/alcohol-soluble π-conjugated materials: new materials and growing applications in solar cells

A novel, amphiphilic, conjugated block copolymer is described, which was prepared by a Suzuki-type cross-coupling of 2-bromo-[9,9-bis(2-ethylhexyl)fluorene]-7-pinacolato boronate as an AB-type monomer and monobromo-substituted poly[3-(6-bromohexyl)thiophene] (Br-P3BrHT) as a polymeric end capper in the key step. PF-P3PHT (P2; PF = poly(9,9-dialkylfluorene); P3PHT = poly[3-(6-diethylphosphonato-hexyl)thiophene]) as the amphiphilic target polymer was then generated in a polymer-analogous conversion of the alkyl bromide side chains of the PF-P3BrHT (P1) precursor into polar alkyl phosphonate groups by reaction with triethyl phosphite. P2 shows a strong influence of the solvent polarity on the optical spectra (absorption, emission). Treatment of solutions of P2 in tetrahydrofuran (THF), a nonselective solvent, with increasing amounts of solvents that are selective for the polar polythiophene blocks (water) or the nonpolar polyfluorene blocks (hexane), respectively, results in the formation of two different types of core-shell aggregates, which show rather different optical properties (photoluminescence quenching, excitation energy transfer).

Amphiphilic Conjugated Block Copolymers: Synthesis and Solvent‐Selective Photoluminescence Quenching

We report a straightforward two-step synthesis toward conjugated DAD-type triblock copolymers with both electron-donor (D) and electron-acceptor (A) blocks. Cyano-substituted poly(phenylenevinylene) (CN−PPV) prepolymers with two bromide end groups hereby act as the central electron-acceptor building block and are generated under Yamamoto conditions. The dibromo prepolymers are finally coupled with monobromo-terminated regioregular poly(3-hexylthiophene) (P3HT), which is selected as the electron-donor block (D). The molecular weight of the different blocks, especially the acceptor block, can be controlled by adjusting the polymerization time and the substitution pattern (degree of alkyl substitution) of the monomers. Elemental analysis, NMR, DSC, and optical spectroscopy prove that the DAD conjugated triblock copolymers. Atomic force microscopy (AFM) images of one triblock copolymer (P3HT1−HCNPPV−P3HT1) exhibit the formation of regular nanosized mesostructures in thin films. The resulting conjugated triblo...

Conjugated triblock copolymers containing both electron-donor and electron-acceptor blocks

The hole mobility and power conversion efficiency of bulk heterojunction solar cells based on P3HT-type donor polymers and the soluble fullerene derivative [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) as an acceptor both show a strong sensitivity to the introduction of interchain branches into the P3HT backbones. Branched B-P3HT copolymers display a distinctly decreased hole mobility and reduced solar cell power conversion efficiency with increasing amount of interchain 3.3'-bithiophene branches within the polythiophene macromolecules. The results illustrate the primary importance of proper solid state packing towards optimum charge transport and solar cell performance.

Guoli Tu

Papers

Amphiphilic Conjugated Block Copolymers: Synthesis and Solvent‐Selective Photoluminescence Quenching

Conjugated triblock copolymers containing both electron-donor and electron-acceptor blocks

The influence of interchain branches on solid state packing, hole mobility and photovoltaic properties of poly (3-hexylthiophene) (P3HT)