| 摘要: | 染料敏化太陽能電池(dye-sensitized solar cells, DSC)中電解液扮演著傳遞載子和再生染料的功用，I-/I3-是目前最常見的氧化還原對，而常見的共軛陽離子為imidazolium和lithium。共軛陽離子或其他添加物能調整TiO2傳導電帶能階位置與增加TiO2膜表面覆蓋度，進而影響元件的光伏表現。本研究主要是藉由調變電解質中各成分的濃度，找出應用於本實驗室所開發之BTI系列有機染料的最佳電解質組成。BTI系列染料的LUMO能階都很低，沒有足夠驅動力將電子從染料的LUMO注入到TiO2傳導電帶能階，因此電解質成分的優化須考慮周全。以BTI-1染料為例，其LUMO只比TiO2傳導電帶能階高0.12 eV，當電解質組成條件為(0.1 M LiI, 0.6 M BMII, 0.5 M GuSCN, 0.5 M tBP, 30 mM I2)時效率只有1.74 %，但提高LiI、BMII及GuSCN濃度到 (1.0 M LiI, 1.2 M BMII, 1.0 M GuSCN)時，效率增加至4.02 %。主要是因為Li+可以降低TiO2傳導電帶能階，提高電子注入效率，增加元件之Jsc。此外，本研究也發現有兩層散射層的TiO2膜，相較一層散射層表面較平整，可增加元件之FF，因此效率也較高。;In dye-sensitized solar cells (DSC), electrolyte plays the role of transferring carrier to the counter electrode and the regeneration of the oxidized dye. The most common electrolyte used in DSC is iodide/triiodide (I-/I3-) redox couple with Imidazolium and lithium as counter cations. Counter cations and other additives in the electrolyte can adjust the level of TiO2 conduction band edge or protect the surface of TiO2 electrode to affect the photovoltaic performance of the correspond cells. The objective of this study is to seek an optimal electrolyte components to be used for a series of organic BTI-X sensitizers prepared in our Lab. These dye molecules have low LUMO level, therefore the electrolyte used should be concerned very carefully. For example BTI-1, when the electrolyte composition condition is 0.1 M LiI, 0.6 M BMII, 0.5 M GuSCN, 0.5 M tBP, 30 mM I2 the efficiency of BTI-1 base DSC is 1.74%. When the concentrations of LiI, BMII and GuSCN increase to 1.0 M LiI, 1.2 M BMII, 1.0 M GuSCN, respectively, the efficiency of the corresponding device increases to 4.02%. This result is attributed to the lowering of the TiO2 conduction band edge improvethe electrons injection from excited dye to TiO2. In addition, the study also found that cell used TiO2 film with two scattering layers shows higher FF, due to the TiO2 film with two scattering is smoother than that with one scattering layers. |
