12/28專題演講公告

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上層分類：系所公告

分類：演講

建立於 2015-12-21, 週一 15:16

最近更新於 2015-12-23, 週三 15:50

發佈於：2015-12-21, 週一 15:43

點擊數：2523

演講人：呂育瑋、施彥辰 博士候選人

演講題目：二氧化鋯與二氧化鉿奈米雙層薄膜之鐵電性研究、鈣鈦礦太陽能電池：從材料到元件，1%到17%

 

演講人：呂育瑋、施彥辰 博士候選人

服務單位：臺灣大學材料系

演講題目：1. 二氧化鋯與二氧化鉿奈米雙層薄膜之鐵電性研究

　　　　　2. 鈣鈦礦太陽能電池：從材料到元件，1%到17%

演講時間：104.12.28 10:20~12:10

演講地點：工綜館203室

 

呂育瑋

 

二氧化鋯與二氧化鉿奈米雙層薄膜之鐵電性研究

Ferroelectricity of Nanometer-thick Bilayer Thin Films of Zirconia and Hafnia

Recently, HfO₂-based system was reported to have ferroelectricity. Doped-HfO₂, binary Hf_1-xZr_xO₂ and undoped-HfO₂ film on TiN electrode have ferroelectricity in particular experimental condition. The high-pressure and high-temperature orthorhombic phase having noncentrosymmetric Pbc2₁ space group, which is induced by encapsulation of TiN electrode, has been claimed as the origin of ferroelectricity in HfO₂. Although simple application based on ferroelectric HfO₂-based system has been made, the mechanism forming ferroelectric HfO₂ is not fully understood. In the present study, bilayer ZrO₂/HfO₂ film fabricated by ALD on Pt/Ti/SiO₂/Si substrate has been determined to have ferroelectricity. The mechanism that how ZrO₂ and HfO₂ in bilayer specimen forming ferroelectric phase and the factors influencing the phase transition is tried to be explained by combining the results of structural information, characteristic hysteresis loop, chemical analysis and phase diagram. With knowing the mechanism forming ferroelectric HfO₂ and anti-ferroelectric ZrO₂, it is believed that the two material systems have potential to be used as new lead-free ferroelectric material in near future.

 

施彥辰

 

鈣鈦礦太陽能電池：從材料到元件，1%到17%

Perovskite Solar Cells:

From Materials to Devices, from 1% to 17%

Recently, organometal halide perovskite solar cells have attracted much attention due to their high power conversion efficiency and potentially low cost for manufacturing. The reported record now is over 20% for power conversion. However, there are so many unknown techniques that the papers won’t tell you. To make a workable device, we need to consider the purity of materials and the method for film deposition. In our research, several amino acids were applied to modify the TiO₂/CH₃NH₃PbI₃ heterojunction interface for reducing the inevitable defects formed during crystallization of perovskite, and higher coverage of the CH₃NH₃PbI₃ crystals with preferential orientation on the TiO₂ surface was obtained, resulting in more efficient charge transfer and higher photocurrent. Based on our results, we believe that this promising modification has created a new breakthrough for the research of perovskite solar cell.