因為硒類前驅物通常難以溶於水相中，因此很難在水相下合成具形狀及尺寸控制的金屬硒化物奈米粒子。在本篇論文中，我們成功的在水溶液及溫和的條件下合成具形貌及尺寸控制的硒化銅奈米粒子。我們利用調整氫氧化鈉的量來控制硒化銅奈米粒子的尺寸，並深入探討反應機制，了解控制奈米粒子的形狀及尺寸的機制。我們觀察到硒化銅奈米粒子的能隙隨著其尺寸的增長而變小，即使硒化銅奈米粒子的尺寸大於其波爾半徑，其能隙仍然持續變化，這個現象無法用量子侷限效應來解釋，並證明了奈米粒子的尺寸光學效應。此外，硒化銅在近紅外波長的區域有明顯的吸收，我們利用光熱實驗證實了此區域的吸收是源自於硒化銅奈米粒子的等離子體性質。

Since selenide sources generally cannot be dissolved in water directly, the synthesis of size- and shape-controlled metal selenide nanocrystals in aqueous phase is rarely reported. In this study, we have developed an efficient way to synthesize Cu3Se2 nanocubes in aqueous solution under mild condition. The Cu3Se2 nanocubes ranging from 35 nm to 86 nm were synthesized by adjusting the amount of NaOH added, and the formation mechanism is discussed. We can observe the band gap of Cu3Se2 nanocubes decreasing with increasing particle size. Even though the nanocubes are fairly large, their band gaps still exhibit continuous shifts, in contrary to the known quantum confinement effects. In addition, their intensive plasmon absorption peak in NIR region makes them a potential candidate for photothermal applications.

摘要 I
ABSTRACT II
TABLE OF CONTENTS III
LIST OF TABLES V
LIST OF FIGURES VI
LIST OF SCHEME IX
1 Introduction 1
1.1 Size- and shape-tunable metal selenide nanocrystals 3
1.2 Copper selenide 7
1.2.1 Synthesis of Cu3Se2 nanocrytals in organic phase 8
1.2.2 Synthesis of Cu3Se2 nanocrystals in aqueous phase 9
1.3 Selenium source 10
2 Experiment Section 13
2.1 Chemicals 13
2.2 Synthesis of Na2SeSO3 13
2.3 Synthesis of Cu3Se2 nanocubes with tunable size 14
2.4 Photothermal measurements 16
2.4.1 Irradiated by 808 nm laser 16
2.4.2 Irradiated by 1064 nm laser 17
2.5 Test of the NaOH concentration effect 17
2.6 Instrumentation 18
3 Results and Discussion 19
3.1 Formation mechanism and characterization of Cu3Se2 nanocubes 19
3.2 The influence of NaOH 24
3.3 Optical properties 26
3.4 Plasmonic properties 28
4 Conclusion 31
5 References 32

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