原子級厚度之二維鈣鈦礦氧化物在鈣鈦礦太陽能電池中電子傳輸層的應用

Two-dimensional atomically thin perovskite oxide as electron transport layer for perovskite solar cells

蔡詠涵(Yung-Han Tsai)

指導教授 ： 陳俊維

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201801306

摘要

二維氧化物是二維材料中的一大類別，而二維氧化物又可以區分成兩個小類：二維金屬氧化物及二維鈣鈦礦氧化物。二維氧化物有相當多元的結構及電性，因其具有量子侷限效應及表面效應，二維氧化物相較於其塊材，具有許多特殊的物理及化學性質，二維氧化物常用於電容、二次電池及催化劑領域中。
Ca2Nb3O10 (CNO)是鈣鈦礦結構的二維氧化物，他是一種N型寬能隙的半導體，其導帶底部位置與常用於太陽能電池吸光層的有機-無機鈣鈦礦接近，因此CNO相當適合作為有機-無機鈣鈦礦太陽能電池的電子傳輸層，用來接收吸光層產生的電子，且不讓電洞進入。此外，相較於一般需要高溫(> 500 ˚C)燒結的二氧化鈦電子傳輸層，CNO的鍍膜僅須相對低溫(< 150 ˚C)的溶劑製程。
本論文中，使用低溫的Langmuir-Blodgett沉積法來製作CNO電子傳輸層，並製做成有機-無機鈣鈦礦太陽能電池，最好的元件效率為14.10%，與一般高溫二氧化鈦電子傳輸層製成的元件效率相當(14.07%)，另外，CNO電子傳輸層擁有更好的電子傳輸能力。論文中證明了CNO是非常有潛力的電子傳輸層，可用來製做全鈣鈦礦結構的太陽能電池。

關鍵字

二維氧化物 ； Ca2Nb3O10 ； 鈣鈦礦氧化物 ； 鈣鈦礦太陽能電池 ； 電子傳輸層

並列摘要

Two-dimensional (2D) oxides are a large group of 2D materials. These 2D oxides can be divided into two subgroups: 2D metal oxides and 2D perovskite oxides. They are rich in structural diversity, electronic properties, and have novel physical and chemical properties from quantum confinement or surface effects comparing to their bulk states. 2D oxides are widely applied in the nanocapacitors, secondary batteries, and photocatalysts fields.
Among the 2D perovskite oxides, Ca2Nb3O10 (CNO) atomic sheet is an n-type wide bandgap semiconductor. It has well aligned conduction band minimum with that of the lead halide perovskite, which is an efficient light absorber for solar cell application. These properties make CNO a promising electron transport material to extract electrons and block holes from lead halide perovskite light absorber. On the other hand, comparing to the conventional high temperature (> 500 ˚C) sintered compact-TiO2 electron transport layer, CNO can be deposited with relative low temperature (< 150 ˚C) solution process.
In this work, we deposited CNO with low temperature Langmuir-Blodgett deposition method as electron transport layer to fabricate perovskite solar cell. The resultant devices showed best efficiency of 14.10%, which is compatible to the conventional high-temperature sintered compact-TiO2 device (14.07%). Moreover, the CNO based devices showed better electron transport ability than the conventional ones. Our work showed that CNO atomic sheet is a highly promising electron transport material for low-temperature solution processed all perovskite structure solar cells.

並列關鍵字

Two-dimensional oxide ； Ca2Nb3O10 ； perovskite oxide ； perovskite solar cell ； electron transport layer

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