-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

Solution-processed bulk-heterojunction solar cells have gained serious attention during the last few years and are becoming established as one of the future photovoltaic technologies for low-cost power production. This article reviews the highlights of the last few years, and summarizes today's state-of-the-art performance. An outlook is given on relevant future materials and technologies that have the potential to guide this young photovoltaic technology towards the magic 10% regime. A cost model supplements the technical discussions, with practical aspects any photovoltaic technology needs to fulfil, and answers to the question as to whether low module costs can compensate lower lifetimes and performances.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.200801283

Polymer‐Fullerene Bulk‐Heterojunction Solar Cells

Stability/degradation of polymer solar cells

On the basis of theoretical models and calculations, several alternating polymeric structures have been investigated to develop optimized poly(2,7-carbazole) derivatives for solar cell applications. Selected low band gap alternating copolymers have been obtained via a Suzuki coupling reaction. A good correlation between DFT theoretical calculations performed on model compounds and the experimental HOMO, LUMO, and band gap energies of the corresponding polymers has been obtained. This study reveals that the alternating copolymer HOMO energy level is mainly fixed by the carbazole moiety, whereas the LUMO energy level is mainly related to the nature of the electron-withdrawing comonomer. However, solar cell performances are not solely driven by the energy levels of the materials. Clearly, the molecular weight and the overall organization of the polymers are other important key parameters to consider when developing new polymers for solar cells. Preliminary measurements have revealed hole mobilities of about ...

Toward a rational design of poly(2,7-carbazole) derivatives for solar cells.

Low band gap polymers for organic photovoltaics

A series of poly(3-hexylthiophene)s (P3HTs) and poly(3-butylthiophene)s (P3BTs) with predetermined molecular weights and varying polydispersities are prepared using a simplified Grignard metathesis chain-growth polymerization. Techniques were elaborated to prepare extremely high molecular weight P3HT (number-average molecular weight of around 280 000 g mol–1) with a low polydispersity (< 1.1) without resorting to fractionation. Optimization of the annealing of a series of solar cells based on blends of poly(3-alkylthiophene)s (P3ATs) and [6,6]-phenyl C61 butyric acid methyl ester indicates that the polydispersities, molecular weights, and degrees of conjugation of the P3ATs all have an important impact not only on cell characteristics but also on the most effective annealing temperature required. The results indicate that each cell requires annealing treatments specific to the type of polymer and its molecular weight distribution.

High molecular weights, polydispersities, and annealing temperatures in the optimization of bulk-heterojunction photovoltaic cells based on poly(3-hexylthiophene) or poly(3-butylthiophene)

Accelerated lifetime measurements of P3HT:PCBM solar cells

Photo- and thermal degradation of MDMO-PPV:PCBM blends

This article is devoted to the study of the photoaging and thermal aging of poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV; also called OC1C10-PPV) used in organic solar cells. Thin MDMO-PPV films (thickness 300 nm) in the presence of air or thermooxidized at 60°C. The modifications of the chemical structure of the matrix were analyzed with ultraviolet-visible and infrared spectroscopy. The oxidation products that formed were identified by postirradiation treatments, including chemical derivatization reactions. On the basis of the identification of the various products formed, a two-step radical mechanism is proposed to account for the modification of the chemical structure of the polymeric matrix. It involves first the oxidation of the ether substituent followed by the oxidation of the double bonds. These reactions are responsible for a loss of conjugation of MDMO-PPV, chain scissions, and a decrease in the visible absorbance, which are anticipated to drastically impair the photovoltaic properties of the material.

Muriel Firon

Papers

High molecular weights, polydispersities, and annealing temperatures in the optimization of bulk-heterojunction photovoltaic cells based on poly(3-hexylthiophene) or poly(3-butylthiophene)

Accelerated lifetime measurements of P3HT:PCBM solar cells

Photo- and thermal degradation of MDMO-PPV:PCBM blends

Aging of a donor conjugated polymer: Photochemical studies of the degradation of poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylenevinylene]

Durability of MDMO-PPV and MDMO-PPV: PCBM blends under illumination in the absence of oxygen