The power conversion efficiency (PCE) of organic photovoltaic (OPV) modules with 9.5% (25 cm2) and 8.7% (802 cm2) have been demonstrated. This PCE of the module exceeded our previous world records of 8.5% (25 cm2) and 6.8% (396 cm2) that were listed in the latest Solar Cell Efficiency Tables ver.43 [1]. Both module design and coating/patterning technique were consistently studied for module development. In order to achieve highly efficient modules, we increased the ratio of photo-active area to designated illumination area to 94% without any scribing process and placed insulating layers in order to decrease the leakage current. The meniscus coating method was used for the fabrication of both buffer and photoactive layers. This technique ensures the fabrication of uniform and nanometer order thickness layers with thickness variation less than 3%. Furthermore, the PCE of the OPV under indoor illumination was found to be higher than that of the conventional Si type solar cells. This indicates that OPVs are promising as electrical power supplies for indoor applications. Therefore, we have also developed several prototypes for electronics integrated photovoltaics (EIPV) such as electrical shelf labels and wireless sensors embedded with our OPV modules, which can be operated by indoor lights.

SYNOPSISPolyimide resists developable with basic aqueous solutions were realized by polyamic acid esters with phenol moieties ( PPh's) and naphthoquinone diazides. The polyimide precursors ( PPh's) were synthesized from diamines and dicarboxylic acids that have phenol moieties through ester linkage. A selective reaction of alcohol groups with acid dianhydride groups made the synthesis of the PPh's possible, even if the phenol groups were in the reaction mixtures. The PPh's were soluble in basic aqueous developer, but their dissolution rates were too low for use as resists. To increase the resist dissolution rate, polyamic acids were added to the PPh's. By adjusting the dissolution rates in basic aqueous developers, fine patterns could be realized. The polyimide resists had high thermal stability and reliable adhesive property to silicon substrate.

SYNOPSISPositive and negative photosensitive polyimides developable with basic aqueous solutions are reported. The results consist of poly amic acids and naphthoquinone diazides in which sulfonate groups have to be substituted at 4-position. It depends on the naphthoquinone structures whether positive or negative patterns are obtained. In order to fabricate resist patterns, High-Temperature-Post-Exposure-Process (HIT-PEB) must be utilized. The reaction mechanisms are also discussed.

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