| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 99 === In this study, we found that the formation of p–i–n junction through in situ electrochemical doping is a promising way to enhance the performance of polymer photovoltaic devices. We applied a pre-bias to metal triflate [LiCF3SO3, KCF3SO3, Ca(CF3SO3)2, Zn(CF3SO3)2] /poly (PEO)–incorporated poly (MEH-PPV)/(PCBM) photovoltaic devices to form p–i–n junctions in their active layers. Auger depth profile analyses and Alternating-current capacitance analyses of these doped devices revealed that the positive and negative ions distributed unequally to form an asymmetrical p-i-n structure in a thin layer of c.a. 100nm and the intrinsic layer became thinner when formed under a higher pre-bias voltage, respectively. Atomic force microscopy and transmission electron microscopy revealed that the addition of metal triflate/PEO to MEH-PPV/PCBM improved the morphology of the composite films. Among the various doped devices, the MEH-PPV/PCBM device incorporating a LiOTf/PEO mixture exhibited the highest power conversion efficiency, a 40% increase relative to that of the reference device (MEH-PPV/PCBM).
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