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In order to improve the P3HT/PCBM polymer photovoltaic devices, C70-PCBM ([6,6]-phenyl C71-butyric acid methyl ester) was employed instead of C60-PCBM ([6,6]-phenyl C61-butyric acid methyl ester). C70-PCBM showed significant increase of visible region light absorption to enhance the photocurrent. To optimize the device performance, we changed the device fabrication conditions such as atmosphere, solvents, post-annealing time, active layer materials composition, and thickness. The best power conversion efficiency of 4.7% was achieved under AM 1.5 G, 75 mA/cm2 condition. [ABSTRACT FROM AUTHOR]

Two interlayers, blended interlayer based on TPD-oxetane with PFO-TPD-OCH3 and crosslinkable polymer interlayer based on Poly(RO2-spiro-TPA-oxetane), were introduced in polymer light-emitting diodes (PLEDs). Both interlayers showed resistance to organic solvents and the performance of PLEDs was greatly enhanced when each interlayer was inserted. The maximum luminescence efficiency of 0.147 cd/A at 11 V and the maximum luminescence of 739 cd/m2 at 15 V have been achieved with blue light emitting polymer, Poly(RO2-spirobifluorene). [ABSTRACT FROM AUTHOR]

Three novel alternating copolymers containing 9,9-dioctylfluorene and thiophene derivatives, poly[(9,9-dioctylfluorene-2,7-diyl)-alt-(4,4'-bis(3''-hexyl-2''thienyl)-biphenyl-5”,5''-diyl)] (P1), poly[(9,9-dioctylfluorene-2,7-diyl)-alt-(5,5'-bis(3''-hexyl-2”thienyl)-2,2'-bithiophenyl-5”,5''-diyl)] (P2), and poly[(9,9-dioctylfluorene-2,7-diyl)-alt-(5,5'-bis(3''-hexyl-2''thienyl)-2,2'-biselenophenyl-5”,5''-diyl)] (P3) were synthesized by a palladium-catalyzed Suzuki polymerization. The synthesis, thermal stability, as well as the optical and electrochemical properties of these polymers are systematically investigated. The polymers were thermally stable up to 400°C, and readily soluble in common organic solvent. The absorption and emission maxima of the copolymers varied according to the type of incorporated aromatic group (thiophene, selenophene, or phenylene). [ABSTRACT FROM AUTHOR]

We have fabricated organic solar cells using highly conductive poly 3,4-ethylenedioxythiophene: poly styrenesulfonate (PEDOT:PSS), which are modified by adding 5 wt. -% ethylene glycol (EG) as an anode without using transparent conducting oxide (TCO). The conductivity of the modified PEDOT:PSS (PEDOT:PSS-EG) film with ethylene glycol (EG) additive was enhanced by three orders of magnitude. With the modified PEDOT:PSS film, we investigated the transmittance of visible range light at various film thicknesses and device performance levels on ITO-free organic solar cells-based highly conductive polymer anodes. The power conversion efficiency (PCE) was governed by the series resistance, which directly determines a short circuit current density (Jsc). [ABSTRACT FROM AUTHOR]