Poly P3HT/PCBM

To improve the limit-of-detection, we replaced the 16 mm vacuum deposited CuPc/Cgg bilayer devices with 1 mm solution-processed polymer devices based on 1 1 blends by weight of poly(3-hexylthiophene) [P3HT] and [6, 6]-phenyl-C61-butyric acid-methylester [PCBM] - a soluble derivative of Ceo- The P3HT PCBM devices fabricated in our laboratory typically have very low short-circuit dark current densities of <10 mA cm , and are consequently a good choice for high sensitivity detection [21]. The... 

Significant amount of research has been dedicated to two material systems MDMO-PPV PCBM (MDMO-PPV poly(2-methoxy-5-(3, 7 -dimethyl-octyloxy)-l,4-phenylenevinylene)) and RR-P3HT PCBM, which represent the state-of-the-art polymer solar cell technology. Because there are excellent review papers on the MDMO-PPV PCBM system in the literature, in this section we will only focus on the recent improvements in RR-P3HT PCBM system, especially the approaches to optimize the active blend layer for enhancing device efficiency. 

Composite films of P3HT/PCBM (poly[3-hexylthiophene-2,5-diyl] and [6,6]-phe-nyl C61 butyric acid methyl ester), which are widely used as the active layer in plastic solar cells [69,70], presented an increased performance when annealed above 100 °C [73]. When comparing the structural and optical properties of such films, using XRD and SE, the increased crystallinity of P3HT was found to be responsible for the increased optical absorption in the visible region. In combination with an enhancement of hole mobility, this would lead to a higher power conversion efficiency of annealed P3HT/PCBM solar cells. 

Figure 9.1 (a) TEM image of thermal annealed P3HT PCBM blends the clear poly-... 

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