氧化銀與金奈米粒子分別對有機薄膜型太陽能電池之陽極與電洞傳輸層改質研究

Anode and Hole-transport Layer Modifications Using Respectively Silver Oxide Nanoparticles And Gold Nanoparticles For Performance Enhancement Of An Organic Solar Cells

郭義文(Kuo, IWen)

指導教授 ： 何正榮

國立中正大學/工學院/機械工程學系/碩士(2012年)

摘要

本文主要在探討利用簡單的摻雜塗佈方法，分別對有機太陽能電池的陽極和電洞傳輸層進行改質，進而提升太陽能電池的光電轉換效率，由於金屬粒子在奈米尺寸下有獨特的光學和物理特性，在此研究中主要利用硝酸銀水溶液對陽極進行改質，利用金奈米粒子摻雜於PEDOT:PSS電洞傳輸層對其改質，結果顯示此雙層改質下更增進了太陽能電池的轉換效率。

本研究的第一部分是對於之前文獻使用耗時耗能的熱蒸鍍方法，將銀蒸鍍在元件上，提出了新的方法改良製作方法，利用硝酸銀容易還原以及易溶於水的特性，將硝酸銀直接以不同的重量百分比摻混於去離子水溶液中，塗佈於陽極ITO玻璃的表面，接著利用加熱的方式還原出銀奈米粒子，再將銀奈米粒子處理成氧化銀奈米粒子，利用氧化銀的功函數(Work function)介於陽極及電洞傳輸層之間，使陽極和電洞傳輸層之間形成更好的歐姆接觸(Ohmic contact)，降低之間的能障(Energy barrier)，使更有利於電洞之傳輸，文獻中使用蒸鍍銀薄膜的方法會使入光的穿透率大為降低，本研究的方法由於銀奈米粒子為散狀分布，故對入光之穿透率影響甚小，而對於陽極改質後的有機太陽能元件的光電轉換效率提升了18%左右。

本研究的第二部分為利用23 nm的水相金奈米粒子，利用表面帶有負電荷的特性，讓金奈米粒子能夠因為靜電排斥力能均勻的分散於PEDOT:PSS中，成功的利用金奈米粒子表面的電漿特性提高光電流，經由PL量測也可發現摻雜水相金奈米粒子可以提升約37.8%的PL強度，提升了整體太陽能元件的光電轉換效率從2.47%到3.37%約提升36%。

關鍵字

有機型太陽能電池 ； 功函數 ； 金奈米粒子 ； 硝酸銀

並列摘要

Based on the spin coating method, this study aims to enhance the performance of an organic solar cell through modifying properties of anode and hole transport layer using metallic nanoparticles. The oxidized silver nanoparticles, (AgOx-NPs) are used to modify the property of the ITO (indium tin oxide) anode and the gold nanoparticles (Au-NPs) are employed to amend the characteristics of the PEDOT:PSS hole transport layer.
The silver nitrate solution was first spin-coated on the top of an ITO glass slide. The silver nanoparticles, Ag-NPs, were generated by thermal reduction. The amount and size of the resulting Ag-NPs are dependent on the concentration of the silver nitrate solution and the thermal reduction time. The resulting ITO/AgOx-NPs substrate was then obtained by exposing the ITO/Ag-NPs substrate to the ultraviolet-ozone irradiation that oxidized the Ag-NPs into AgOx-NPs. Since the work function of AgOx is between the PEDOT:PSS hole transport layer and the ITO anode, a better in-between ohmic contact was expected that resulted in reducing the energy barrier and boosting transport of holes. Compared with the AgOx NPs in the literature, where a silver thin film was first deposited using thermal evaporation, the present approach takes the advantage that the AgOx is presented in the nanoparticles that insignificantly affect light penetration and absorption. Results show a solar cell device with the enhancement of the overall energy conservation efficiency up to 22% was achievable.
The employed Au-NPs for modifying the PEDOT:PSS hole transport layer were negatively surface charged and with diameters around 23 nm. The surface electrostatic repulsion helped the NPs dispersing uniformly in the PEDOT:PSS/Au-NPs solution and the resulting thin film as well. The photoluminance (PL) measurement indicated, with the existence of the Au-NPs, an about 38% enhancement in PL intensity within the wavelength range of 600 – 700 nm was obtainable and the resulting device PCE (photoelectric conversion efficiency) was 36% enhancement, from 2.47% without Au-NPs to 3.37% with Au-NPs.

並列關鍵字

organic polymer solar cells ； work function ； gold nanoparticles ； silver nitrate

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