應用於染料敏化太陽能電池之新穎苯架橋雙錨基材料的設計與合成

Design and Synthesis of Novel Benzene-Bridged Double D-π-A Materials for Dye-Sensitized Solar Cells

楊文鳳(Wen-Feng Yang)

指導教授 ： 汪根欉

國立臺灣大學/理學院/化學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201601454

摘要

一般單錨基染料因其構形為棒狀結構，使染料容易有堆疊現象，導致電子注入效率下降，而雙錨基染料可以形成類螺旋的構形，有效抑制分子間的作用力，因此可以抑制暗電流的產生。本論文探討雙錨基染料分子結構、光物理性質以及元件效率表現之間的關係。在本論文中，我們設計與合成了兩個新穎苯架橋雙錨基染料p-BTTA與m-BTTA，兩個染料的主要差異在於苯環架橋連接的位置不同，雙錨基染料p-BTTA是以苯環的對位做為架橋，而m-BTTA則是以苯環的間位做為架橋。
在溶液態吸收光譜的表現中，由於雙錨基染料p-BTTA與m-BTTA延長了π共軛系統，可以觀察到其與結構類似的單錨基染料D21L6相比均有較寬與較強的吸收行為。雙錨基染料p-BTTA與m-BTTA相比，其表現出的消光係數較大，由理論計算結果可得p-BTTA結構中共軛區的平面性佳，因此對光子捕獲的能力較佳。由於雙錨基染料有較大的消光係數，因此有較佳的光捕獲率，使元件效率與D21L6 (效率5.33%) 相比均有更佳的表現。在單色光光電轉換效率中，m-BTTA在波長350奈米到630奈米表現中均超過80%，並在波長500奈米的位置有90%的光電轉換效率。因此，m-BTTA染料在使用碘電解質的條件下可達效率7.48%，是相同實驗條件下標準元件N719 (效率7.59%) 的98.6%表現。而p-BTTA受限於溶解度的影響，效率只能達到6.06%。
在第三章中，探討嘧啶對於染料結構的影響，分別設計出含嘧啶受體的染料OHexDPTP-BTBA與對照組M-TP-BTBA。由於在嘧啶結構中，無鄰位氫的立體障礙，使分子結構中的共軛區平面性可以提升，有助於電荷轉移。由元件結果可得，OHexDPTP-BTBA有不錯的短路電流16.13 mA/cm2，開路電壓為0.70 V，可以獲得7.45%的效率表現。

關鍵字

染料敏化太陽能電池 ； 雙錨基染料

並列摘要

As compared to the rod-shape of the single D-π-A analogue dye (D21L6), the twisted shape of the double D-π-A branched dye is favorable for reducing intermolecular interaction and retarding dark current. The relationship among the chemical structures, optoelectronic properties and device performance has been systematically investigated. In this work, novel benzene-bridged organic dyes (designated p-BTTAand m-BTTA) have been designed and synthesized for dye-sensitized solar cells (DSCs). The structural difference between the two sensitizers is the position of bridge.
Double D-π-A dye of p-BTTA and m-BTTA result in a broader and more intense charge transfer band in comparison to those of D21L6 because of extending π-conjugated framework. p-BTTA yields higher molar extinction coefficient than m-BTTA due to better planarity in conjugated reginon. m-BTTA and p-BTTA yield higher molar extinction coefficient than that of D21L6 which can improve light-harvesting capacity and demonstrate better solar cell performance than D21L6. The monochromatic incident photon-to-current conversion efficienc of m-BTTA-based DSCs exceeds 80% in abroad spectral region covering from 350 to 630 nm and reaches its maximum of 90% at 500 nm. Consequently, a high power conversion efficiency of 7.48% is achieved for a DSCs based on sensitizer m-BTTA using a liquid electrolyte, which reaches approximately 98.6% of the N719-based device (PCE=7.59%) under same condition. The lower conversion efficiency of p-BTTA (PCE=6.06%) is primarily attributed to its poor solubility.
In chapter 3, OHexDPTP-BTBA dye which incorporates electron-deficient pyrimidine as the π-spacer has been designed and synthesized. In comparison with the model compound M-TP-BTBA, which adopts phenylene as the π-spacer, OHexDPTP-BTBA demonstrates better planarity in conjugated reginon which is favorable for effective intramolecular charge transfer. OHexDPTP-BTBA exhibits high power conversion efficiency up to 7.45%, with Voc of 0.70 V, Jsc of 16.13 mA/cm2.

並列關鍵字

Dye-Sensitized Solar Cells ； Double D-π-A Materials

參考文獻

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