MEH-PPV polymer

Nonconjugated poly[l,3-propanedioxy-l,4-phenylene-l,2-ethenylene(2,5-bis(tri-methylsilyl)-l,4-phenylene)- l,2-ethenylene-l,4-phenylene] (DSiPV) and conjugated MEH-PPV polymers are mixed by changing their weight ratios in 1,2-dichloroethane. The films of the blend polymers could be spin-cast from 1,2-dichloroethane solution with excellent reproducibility. AFM (atomic force microscopy) and SEM images show no indication of phase separation or layer formation due to the immiscibility of two polymers. The structures of DSiPV and MEH-PPV are shown in Fig. 24. 

GreenhamN. C., Peng X. and Ahvisatos A. P. (1997), A CdSe nanocrystal/MEH-PPV polymer composite photovoltaic , in McConnell R., ed., Future Generation Photovoltaic Technologies First NREL Conference, Am. Inst. Phys., pp. 295-302. 

Breeze AJ, Schlesinger Z, Carter SA (2001) Charge transport in Ti02/MEH-PPV polymer photovoltaics. Phys Rev B 64 125205... 

Schaller et al. [115] used NSOM to collect local light emission from the surface of MEH-PPV polymer samples in contact with various solvents. The goal of this study was to identify various emissive interchain species present in annealed MEH-PPV films. The... 

MEH-PPV polymer apparently shows very different properties than those of DOO-PPV and PPVDO polymers discussed in Section 22.3.1. Due to its side group the MEH-PPV polymer is able to form an ordered phase when films are cast from bad solvents such as toluene [153,154]. In such films two or more polymer chains are coupled together due to increased interchain interaction, which renders the benzene rings of the polymer backbone to lace each other. Under these conditions the primary excitations and polaron wavefimctions may acquire enhanced 2D delocalization that is in fact spread over two or more chains. Such delocalized photoexdtations were identified in other polymers with improved order such as PFO, mLPPP [54], and regioregular P3HT [72], which will be discussed later. 

In 1994, a polymer-based transistor [237] constructed in a geometry closely related to that of a vacuum tube triode was demonstrated [237]. The structure consists of a thin MEH-PPV polymer film sandwiched between two electrodes, with a third electrode (PANI network) [209, 238-241] embedded within the MEH-PPV film (Fig. 13). This third electrode plays a role similar to that of the grid in a vacuum tube, controlling the current between the two outermost electrodes. Using a generalized analysis based on field-assisted carrier injection by tunneling, the carrier injection and transport in the polymer grid triode could be modeled [242]. 

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