探討金及硒化鎘奈米粒子自身組織排列於PS-b-P4VP雙塊式高分子薄膜之P4VP區塊中之集合電子傳導性質

Abstract

此論文主旨為利用有機PS-b-P4VP雙塊式高分子薄膜自身組織成週期性結構的特性作為模版並以選擇性分散之技術，分別將無機Au、CdSe奈米粒子侷限於P4VP奈米區塊中形成特定結構之奈米陣列，並探討此具有奈米侷限效應之奈米粒子之群體電子傳導特性。 利用導電的原子力顯微鏡及電性量測儀器，針對於具有奈米侷限效應之CdSe量子點/P4VP奈米區塊進行量測，發現電子在此具奈米侷限效應之量子點間之傳導速度遠較不具侷限效應之量子點之傳導速度快。 利用低溫電性量測儀器，針對於具有奈米侷限效應之Au奈米粒子/P4VP奈米區塊進行量測，在78K之低溫量測下，Au奈米粒子具有庫侖阻塞效應，進而發現具有奈米侷限之奈米粒子呈現出趨近於一維電子傳導之特性。 此外，將CdSe奈米柱選擇性分散於P4VP奈米區塊中並在高溫下加入電場作為驅動力，製備出具方向性且大面積規則排列之CdSe/P4VP陣列，並量測加入電場前後之電子遷移速率。

In this dissertation, thin films that consisted of Au and CdSe nanoparticles (NPs), self-assembled in a poly(4-vinylpyridine) (P4VP) nanodomain of poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) diblock copolymer were prepared by polar interaction and solvent selectivity. Collective electron transport of these organic nanodomain confined nanoparticles were investigated. From conductive atomic force microscopy and device measurements, we found that the electron tunneling rate constant in the case of CdSe quantum dots confined in a P4VP nanodomain is much larger than that in the randomly-distributed case. The calculated electron tunneling coefficient for hopping between confined CdSe quantum dots was 0.3 1/Å. The conductivity of the CdSe/P4VP nanodomain increased upon increasing the amount of CdSe, following a percolation model (Chapter 2). From the current–voltage characteristics of PS-b-P4VP thin films that consist of Au NPs, we found that the collective electron transport behavior of Au NPs sequestered in the spherical P4VP nanodomains was dictated by Coulomb blockade and was quasi one-dimensional, as opposed to the three-dimensional behavior displayed by Au NPs that had been dispersed randomly in homo-P4VP (Chapter 3). Moreover, CdSe nanorods self-assembled in the P4VP nanodomains of a PS-b-P4VP diblock copolymer thin film were aligned under the influence of the polarization forces created by an applied electric field. The electron mobilities of CdSe/P4VP nanodomains incorporating the out-of-plane CdSe nanorods were much larger than those incorporating in-plane nanorods (chapter 4).