• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.104-108
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• 2012

Flexible organic thin film solar cell device with Bulk Hetero-Junction (BHJ) structure was fabricated with blended conjugated polymer of PCDTBT : $PC_{71}BM$ as active layer. Surface of ITO anode for the organic solar cell device was treated with ozone. The organic solar cell device with bare ITO showed short circuit current density ($J_{sc}$) of $8.2mA/cm^2$, open-circuit voltage ($V_{oc}$) of 0.73V, fill factor (FF) of 0.36, and power conversion efficiency (PCE) of 2.16%, respectively. The organic solar cell device with ozone treated ITO anode revealed distinctively improved performance parameters:$J_{sc}$ of $9.8mA/cm^2$, $V_{oc}$ of 0.82V, FF of 0.43, PCE(${\eta}$) of 3.42%.

• Journal of the Korean Vacuum Society
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• v.22 no.4
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• pp.211-217
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• 2013

Two types of organic thin film solar cell devices with bulk hetero-junction (BHJ) structure were fabricated on plastic substrates using conjugated polymers of $PCDTBT:PC_{71}BM$ and $PTB7:PC_{71}BM$ blended as active channel layer. Time-variant characteristics of the organic thin film solar cell devices were investigated: short circuit current density ($J_{SC}$); open circuit voltage ($V_{OC}$); ; fill factor (FF); power conversion efficiency (PCE, ŋ). All the performance parameters were degraded by progress of the measurement time, while $V_{OC}$ showed the most drastic decrease with time. Possible factors to cause the time-variant alteration of performance parameters were discussed to be clarified.

• Transactions on Electrical and Electronic Materials
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• v.13 no.1
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• pp.43-46
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• 2012

Organic solar cell devices were fabricated using poly[9-(1-octylnonyl)-9H-carbazole-2.7-diyl]-2.5-thiophenediyl-2.1.3-benzothiadiazole-4.7-diyl-2.5-thiophenediyl] PCDTBT/ [6,6]-phenyl $C_{71}$ butyric acid methyl ester (PC71BM) active layer deposited by spin coating. Moreover, the relationship between solar cell performance and buffer layer thickness was investigated by spin coating speed and AFM imaging of the buffer layer surface. The performance of the organic solar cell with spin-coated active layer was then evaluated, and the power conversion efficiency of the solar cell was determined to be > 5%.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.377-377
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• 2011

Organic solar cells (OSCs) with low cost have been studied to apply on flexible substrate by solution process in low temperature [1]. In previous researches, conventional organic solar cell was composed of metal oxide anode, buffer layer such as PEDOT:PSS, photoactive layer, and metal cathode with low work function. In this structure, indium tin oxide (ITO) and Al was generally used as metal oxide anode and metal cathode, respectively. However, they showed poor reliability, because PEDOT:PSS was sensitive to moisture and air, and the low work function metal cathode was easily oxidized to air, resulting in decreased efficiency in half per day [2]. Inverted organic solar cells (IOSCs) using high work function metal and buffer layer replacing the PEDOT:PSS have focused as a solution in conventional organic solar cell. On the contrary to conventional OSCs, ZnO and TiO2 are required to be used as a buffer layer, since the ITO in IOSC is used as cathode to collect electrons and block holes. The ZnO is expected to be excellent electron transport layer (ETL), because the ZnO has the advantages of high electron mobility, stability in air, easy fabrication at room temperature, and UV absorption. In this study, the IOSCs based on poly [N-900-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) : [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) were fabricated with the ZnO electron-transport layer and MoO3 hole-transport layer. Thickness of the ZnO for electron-transport layer was controlled by rotation speed in spin-coating. The PCDTBT and PC70BM were mixed with a ratio of 1:2 as an active layer. As a result, the highest efficiency of 2.53% was achieved.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.73.2-73.2
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• 2010

Polymer solar cells (PSCs) have attracted considerable academic and commercial interest because of their unique advantages, such as the facile manufacture of low cost, flexibility, lightweight, and solution processibility. Recently, high-performance polymer solar cells made from a mixture of poly(2,7-carbazole) derivatives, PCDTBT, and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) have been reported, with maximum power conversion efficiency of 6.1%. In this work, we report new novel copolymers based on poly(2,7-carbazole) derivatives with a suite of electron-deficient moieties or electron-rich units. We systematically investigated the synthesis, thermal stability, as well as the optical and electrochemical properties of these polymers. Detailed synthetic scheme, optical, electrochemical, and photovoltaic properties of the copolymers will be presented.