新穎軟性熱電複合材料與元件之製備及應用研究：高分子及奈米結構化Bi-Te機能性熱電複合材料

Abstract

新穎軟性熱電複合材料與元件之製備及應用研究，主要於軟性基板上，機能性整合有機導電高 分子與無機Bi-Te 基奈米結構熱電薄膜，使其成為一具有高熱電轉換效率之全軟性複合元件。本研 究計畫架構主要包含三大主題: N 型及P 型導電有機高分子之製備以及熱電性質與結構之調控、於 經表面改質之聚亞醯胺(polyimide, PI)基板上，N 型及P 型無機Bi-Te 基奈米結構之低溫沈積及調控、 有機高分子與無機Bi-Te 基奈米結構複合材料之製備及熱電轉換元件之設計應用。 目前本研究團隊於有機導電高分子研究方面，已具備可調控PEDOT:PSS 導電度與Seebeck 常數 之技術，無機材料方面，可藉由沉積溫度控制N 型及P 型熱電薄膜之方向性及其奈米結構的技術。 以此過去之技術及經驗為基礎，本計畫將更進一步延伸設計及製備出新穎軟性熱電複合材料作為高 性能熱電元件之用。在導電高分子方面，主要利用電沉積(electrodeposition)或旋轉塗佈(spin coating) 技術，調控高分子薄膜之結構方向性、膜厚等結構參數，並進而了解其對熱電性質之影響。此外， 亦將針對不同化合物之混摻，來有效獨立提昇各項熱電相關特性。而無機Bi-Te 基奈米結構之製備， 主要利用脈衝雷射沉積技術(pulsed laser deposition, PLD)，於表面金屬化之PI 基板上，進行一系列 沈積，期藉由各種結構參數之變化，來達到調控各項熱電相關特性。最後則是透過元件技術，將最 佳化之有機-無機熱電薄膜，機能性整合成有機-無機複合薄膜熱電元件，藉由二者各別之優勢搭配， 來達到提升整體複合薄膜熱電元件的效率。

The project entitled ‘Preparation and applications of novel flexible thermoelectric composites and devices: polymer and nanostructured Bi-Te functional thermoelectric composite films’ mainly focus on the functional integration of various organic conducting polymers and inorganic nanostructured Bi-Te thermoelectric thin films on flexible substrates for the approach of novel flexible composites with a high thermoelectric conversion efficiency. Three main topics are included : the preparation of N-type and P-type organic conducting polymers with controlled micro-structures and related thermoelectric properties, the deposition of N-type and P-type inorganic Bi-Te nanostructures onto surface-modified flexible polyimide (PI) substrates at lower temperatures with controlled structural and thermoelectric parameters, and the integration of the conducting polymers and the Bi-Te nanostructures as thermoelectric composites for device applications. Till now, we have already established strategies to modify and control the electric conductivity and Seebeck coefficient of PEDOT:PSS films by chemical or physical techniques. For the inorganic Bi-Te films, not only the conducting type (N or P type) but also the orientation and nanostructures are able to be well controlled by precise adjustment of the deposition parameters. Based on these core techniques, in this plan, we will further extend our research to design and prepare the novel flexible thermoelectric composites for high performance of thermoelectric devices. In the case of conducting polymers, by using the electrodeposition or spin coating techniques, the structural parameters including morphology, orientation and thickness as well as the dependent thermoelectric properties can be controlled. In addition, doping of selected compounds will be also used for the effective controlling and enhancement of thermoelectric properties. Bi2Te3 nanostructures are mainly prepared by pulse laser deposition (PLD) with specific deposition parameters. Finally, we will integrate the optimum conducting polymer and Bi-Te films on PI substrates as novel flexible thermoelectric composites to take the merits of both layers for the further enhancement of thermoelectric properties. .