Abstract
摘要:以可再生與潔淨的太陽能發展高效率及長壽命的光電池持續地增加當中,即使以矽為基材的光電池元件已經可轉換25%的入射太陽光能量,但是它們並不透光而且價格高昂。相對的,日前導電高分子的進展,開啟製作透明的、低重量、可橈曲、且大面積之光電池元件的可能性。然而,大多數光電池元件遭遇低光能轉換效率與穩定性不佳的問題。對於許多導電高分子而言,電子遷移效率相當低,易導致光生成電荷經由複合而消散。若是有第二種的材料,例如奈米粒子,混合進入導電高分子能提供電荷分離與傳輸之作用,便可以克服此問題。目前,一般可以藉由將奈米粒子摻混於高分子溶液中製作奈米粒子/高分子複合材料。奈米粒子會隨意地分佈於高分子中。為了使奈米粒子形成具高度連結的網路結構,奈米粒子一般必須在較高的濃度。但是奈米粒子聚集的問題也時常發生,且往往發生在高濃度奈米粒子之情形下,此現象將使奈米粒子與高分子介面面積降低與介面作用減退,及量子效率的下降。當前高分子-奈米粒子光電池元件之最高值約2.5%,較以矽為基材製作者轉換效率低約十倍。
我們提出一件三年計畫,包含四個項目,運用分子設計及分子模擬的概念,
巧妙操控化學結構、組成、尺度、奈米
Abstract: There has been an ever-increasing interest in the development of high efficiency and long life solar photovoltaic devices using renewable and clean solar energy. Although Si-based photovoltaic devices can harvest up to as much as 25% of the incoming solar energy, they are opaque and costly to make. On the contrary, recent progress in the development of conducting polymers has created the possibility of making transparent, light weight, low cost, flexible and large area photovoltaic devices. However, most organic photovoltaic devices suffer from low efficiency in solar energy conversion and poor thermal stability. For many conducting polymers, electron mobilities are extremely low, and the photo-generated charges lose via recombination. A second material such as nanoparticle incorporated in conjugated polymer provides interface for charge separation and transport could overcome these problems. At present, the nanoparticle/polymer composites for photovoltaic devices are prepared by blending the semiconducting nanoparticle with conducting polymer in solvent. The nanoparticles are randomly distributed in the polymer matrix. In order for the nanoparticles in the polymer matrix to form a highly connected network, usually the nanoparticles have to be in high concentration. Problems of coagulation often occurs from high concentration of nanoparticles and reduce the interfacial interactions between the polymer and nanoparticle which results in decreasing quantum efficiency. Currently, the highest reported power conversion efficiency of polymer-nanoparticle photovoltaic device is an order lower than that of Si based material about 2.5%.
We are proposing a three year project with four tasks using molecular design and molecular modeling concepts to manipulating chemical structures and compositions, size and organization of nanodomain, and interfacial interactions between inorganic nanoparticles and conducting polymers to form novel polymer-nanoparticle hybrid materials. They will be investigated as active materials for the fabrication of high efficient and long life photovoltaic devices. Three strategies will be used to achieve the objective: (1) using thermal stable materials having capability to absorb full solar spectra, (2) increasing interface between polymers and nanoparticles and (3) controlling mechanisms of charge separation and transport.
In the task 1, we will develop thermal stable and high charge mobility nanoparticles with capability to absorb full solar spectra. The nanoparticles should be low bandgap thermal resistant oxide based material. In the first year, we will explore a system that combines II-VI semiconductor and TiO2 nanoparticles either by blending or chemical bonding. In the second year, we will study doped TiO2 nanoparticles. The dopants will be transition metal ions or Lanthanide ions (0.1-3% Wt.) to extend the absorption spectrum of TiO2 from UV range to longer wavelength for high harvest efficiency of solar energy. In the t
Keyword(s)
光電池
奈米粒子
半導體
導電高分子
奈米結構
長壽命
高效率
conducting polymer
nanoparticle
nanostructure
semiconductor
photovoltaic device