Zinc phthalocyanine (ZnPc): fullerene-C60 (C60)-based organic photovoltaic (OPV) with high power conversion efficiency (PCE) are fabricated. Homogeneously distributed grains of ∼40–50 nm are observed for the ZnPc:C60 blend layer deposited on bare indium-tin oxide (ITO) substrates. In contrast, the blend layer form grains of smaller lateral extensions (∼20–30 nm) on 3, 4-polyethylenedioxythiophene: polystyrenesulfonate modified ITO substrates. OPV fabricated on the former substrates show PCE of up to 3.9% that is about twice the PCE (1.9%) obtained for the devices on the latter substrates. This effect can be explained by better transport properties and reduced charge recombination of the blend layer on the bare ITO.
The initiation and termination steps of the anionic polymerization of P=C bonds have been modeled. The initiation step was investigated through the stoichiometric reaction of MesP=CPh2 (1) with RLi (R = Me or n-Bu). In each case, the addition was highly regioselective with the formal attack of R– at phosphorus to give the carbanion Li[Mes(R)P–CPh2] (3a, R = Me; 3b, R = n-Bu). To simulate the termination step in the anionic polymerization of 1, carbanions 3a and 3b were quenched in situ with various electrophiles. Through these reactions, several new tertiary phosphines have been prepared, namely, Mes(Me)P–CPh2H (4a), Mes(n-Bu)P–CPh2H (4b), Mes(Me)P–CPh2Me (6a), Mes(Me)P–CPh2–P(NEt2)2 (7a), Mes(Me)P–CPh2–SiMe2H (8a), and Mes(Me)P–CPh2–SiMe3 (9a). In addition, compounds 4a, 7a, 8a, and 9a were characterized by X-ray crystallography. Most of the metrical parameters are typical of tertiary phosphines; however, the P–CPh2H bonds were elongated in all cases reflecting the considerable steric bulk surrounding this bond. Unexpectedly, an unusually large 31P–31P coupling constant (2JPP > 200 Hz) was observed for 7a both in solution and the solid state. This observation may be rationalized by a through space P···P interaction. This rationale is further supported by the short P···P distance [P(1)—P(2) = 2.966(1) Å; cf. Σ rvdw = 3.7 Å] and a small P–C–P bond angle for 7a [P(1)–C(11)–P(1) = 99.17(9)°].Key words: phosphaalkenes, phosphorus polymers, phosphines, anionic polymerization.
Interaction of NH(3)BH(3) and Li(2)NH (or Li(3)N) in THF leads to the formation of NH(3) and LiNH(2)BH(3), which further react with each other and produce ca. 10 wt.% hydrogen at 45 degrees C.
Titanium oxide (TiOx) modified with a thin layer of Al was used as an electron transporting layer in an inverted organic solar cell based on the P3HT/PCBM blend. The thin Al layer was shown to improve the TiOx surface properties, decreased the work-function of TiOx, increased the built-in voltage, and facilitated electron extraction. As a result, good device performance with power conversion efficiency of 3.6%, open circuit voltage of 0.60 V, short circuit current of 9.13 mA/cm2, and fill factor of 0.66 was achieved. The light soaking problem was eliminated compared to the TiOx only device.
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