用於鈣鈦礦太陽能電池的螺旋型及 U 型電洞傳輸材料

Helicene-Type and U-Shaped Hole Transport Materials for Perovskite Solar Cells

林佑昕(Yeo-Sin Lin)

指導教授 ： 孫世勝

共同指導教授 ： 汪根欉(Ken-Tsung Wong)

國立臺灣大學/理學院/化學研究所/博士(2019年)

https://doi.org/10.6342/NTU201903843

摘要

在第三章，設計合成三種具有不同推電子基團的氮雜螺旋型衍生物，用於鈣鈦礦太陽能電池中的電洞傳輸材料。其中bis(p-methoxyphenyl)amino取代的的衍生物（SY1）的最大光電轉換效率為17.34％，bis(p-methoxyphenyl)aminophenyl取代的衍生物（SY2）的最大光電轉換效率為16.10％。然而，具有長鏈推電子基如己氧基（SY3）則會大大降低效率。此外，用SY1作為電洞傳輸材料製造無摻雜劑的元件平均光電轉換效率為12.13％，顯著高於spiro-OMeTAD（7.61％）。長時間的穩定性測試顯示，在500小時後，由SY1和SY2製備的元件維持了其初始性能的 96％ 以上，這比在相同條件下使用標準品spiro-OMeTAD作為電洞傳輸材料有大幅的改進。同時，材料成本分析中，此論文所使用的材料成本遠低於spiro-OMeTAD的8％。
鑒於螺旋型結構具有許多的優點，在第四章中，開發了另外兩種基於碳硼烷核心便宜且有效率的電洞傳輸材料-CH1及CH2，以實現有效和穩定的鈣鈦礦太陽能電池。由於螺旋核的剛性構象，兩種化合物在多晶堆積模式和井相穩定性中具有獨特且強烈的CH- 作用力，不同於一般平面分子的π-π分子間作用力。令人驚訝的是，CH1和CH2分別能夠達到 > 19％ 和18.71％令人印象深刻的效率，優於標準品spiro-OMeTAD的性能（18.45％）。此外，兩種鈣鈦礦太陽能電池還具良好的環境穩定性，在放置超過500小時以後，仍可維持90％的初始性能。考慮到兩種化合物的低產品成本（

關鍵字

鈣鈦礦太陽能電池 ； 電洞傳輸材料 ； 螺旋型分子 ； U 型分子 ； CH-π作用 力

並列摘要

In chapter 3, three azahelicene derivatives with electron-rich bis(4-methoxyphenyl)-amino or bis(p-methoxyphenyl)aminophenyl groups at the terminals were deliberately designed, synthesized, and characterized as HTMs for PSCs. A maximum PCE of 17.34% was observed for the bis(p-methoxyphenyl)amino-substituted derivative (SY1) and 16.10% for the bis(p-methoxyphenyl)aminophenyl-substituted derivative (SY2). Longer-chain substituent such as hexyloxy group (SY3) greatly diminishes the efficiency. In addition, the dopant-free devices fabricated with SY1 as the HTM shows an average PCE of 12.13%, which is significantly higher than that of spiro-OMeTAD (7.61%). The ambient long-term stability test revealed that after 500 h, the devices prepared from SY1 and SY2 retained more than 96% of its initial performance, which is much improved than the reference device with standard spiro-OMeTAD as the HTM under the same conditions. Detailed material cost analysis reveals that the material cost for SY1 is less than 8% of that for spiro-OMeTAD.
In view of the many advantages of the helicene structure, in chapter 4, another two inexpensive and efficient HTMs based on a carbohelicene core, CH1 and CH2, were developed to realize efficient and stable conventional PSCs. Owing to the rigid conformation of helicene-core, both compounds possess unique and strong CH− interactions in the polycrystalline packing pattern and good phase stabililty, which are distinct from the π−π intermolecular interactions of conventional planar and spiro-type molecules. Surprisingly, CH1 and CH2 derived PSCs delivered an impressive efficiency of > 19% and 18.71%, respectively, outperforming the (18.45%) of control device based on spiro-OMeTAD. Furthermore, both PSCs also possess better ambient stability, for which 90% of initial performance is retained after aging in a dry box with a 30% relative humidity at 28-32°C for over 500 h. Considering the low product cost of both compounds (< 1/10 of that for spiro-OMeTAD), these newly designed carbohelicene-type HTMs are promising potential candidates for the commercialization of PSCs.
Finally, we found that phenanthrene (Phe) combined the advantages of both low-cost and electron-rich aromatic unit, which can be easily obtained by two steps in mild conditions. Herein, we synthesized two low-cost U-shaped HTMs, U1 and U2. From crystal structure, both compounds possess strong CH− interactions in the polycrystalline packing pattern and U1 also has hydrogen bonding force. Surprisingly, U1 and U2 enable their derived PSCs to deliver high efficiency of 18.71 and 17.11%, respectively. Furthermore, both PSCs also possess better ambient stability, for which 85% of initial performance is retained after aging in a dry box for over 500 h.

並列關鍵字

perovskite solar cells ； hole-transporting materials ； helicene-type molecule ； U-shaped molecule ； CH-π interaction.

參考文獻

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