本研究利用水熱法於鹼性環境下合成出具連續一維結構的海膽狀二氧化鈦，並透過改變溶液中的鹼性濃度，獲得混合晶型比例不同的二氧化鈦。發現在不同鹼性濃度下，皆有銳鈦礦(Anatase)及板鈦礦(Brookite)的訊號出現，板鈦礦比例最高可達40%。

在特定鹼性濃度條件下利用不同時間取樣來觀察其合成機制的實驗中，發現板鈦礦晶型伴隨著海膽狀結構一起出現，故推論海膽狀結構可能因板鈦礦晶型的自身應力所造成。

將海膽狀二氧化鈦做為光電極主層進行光電效率測試發現，海膽狀TiO2與商用品CCIC-400在整體的轉換效率表現相近。由電化學頻譜阻抗分析(EIS)測試可以發現，海膽狀TiO2有較高的τeff 值，此意謂著電子在海膽狀TiO2中具有較長的電子存活時間，但由於其結構並非單一晶型組成，而形成結晶錯位的障礙，不利於電子傳導，故電子在傳遞時具有較高Rw。

In this study, the sea urchin-like titanium dioxide particles were synthesized by hydrothermal treatment with changing the concentration of base, the composites with different ratios of brookite and anatase were obtained. The brookite sea urchin-like morphology in the picture shows high uniformity and a clean surface without any contamination, then they were tested through SEM, TEM, XRD and BET.

In the XRD and BET test, we have the detailed informations about phase composition and specific surface area of the above materials. The titanium dioxide particles with different ratios of brookite in the range of 10% to 40% through changing the concentration of base. To observe the surface morphology and particle size, the SEM and TEM images of some samples were carried out.

To understand the formation mechanism, the samples with different reaction times were sampled. And the TEM images of TiO2 show that nanosheets are the key steps in synthesis.

In order to achieve a improvement in energy conversion efficiency of Dye-sensitized solar cells(DSSCs), One possible solution is to increase the electron diffusion length in the anode. Electron transport in crystalline sea urchin-like titanium dioxide particles is expected to be faster than percolation through a random nanoparticle film.

The photovoltaic characterization results show that the differences of the performances of sea urchin-like particles and CCIC-400 are not remarkable. From EIS measurements under open-circuit voltage conditions, We also confirmed that our particles have the better electron diffusion ability by longer effective lifetime ( τeff ) and better short circuit current ( Jsc ) values of DSSCs.

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