寬能隙電子阻擋層改善有機太陽能電池效率

Abstract

本篇論文中，我們於單異質接面有機太陽能電池中，藉由寛能隙電子阻擋層設計技術研製高效率的有機太陽能電池(OPV cell)。在製作的過程中我們使用多種材料來比較其特性，藉以提升元件的光電流吸收效率，平衡載子收集於電極之效率並增進元件開路電壓及短路電流，以進而達到提升效率的目的。 首先，我們嘗試最佳化單異質接面有機太陽能電池結構，其結構為ITO/CuPc (X nm)/C60 (Y nm)/BCP (10 nm)/Al (100 nm)。我們先調變CuPc的膜厚到達最高效率；之後再改變C60的膜厚在以達到最佳結構的最高效率，此元件的開路電壓為0.4 V，短路電流密度為3.96 mA/cm2，填充因數為63.1 %，功率轉換效率為1.00%。 其次，嘗試使用三種寬能隙的電子阻擋層材料在最佳化的單異質接面太陽能電池的結構，材料分別為1. m-MTDATA；2.MeO-TPD；3.Ir(ppz)3，並調整各材料其最佳厚度，其結構為ITO/electron blocking layer/CuPc(30 nm)/C60(40 nm) /BCP(10 nm)/Al(100 nm)。其最佳厚度分別為1. m-MTDATA(4 nm)；2.MeO-TPD (3 nm)；3.Ir(ppz)3(0.5 nm)。 最後，我們選擇了特性最佳的m-MTDATA作為電子阻擋層材料，另外，在電子受體CuPc層用共蒸鍍的方式摻雜高載子遷移率的有機材料 Pentacene，藉由增加Pentacene的濃度我們可以發現元件的短路電流以及效率明顯提升。其結構依序如下ITO/m-MTDATA/CuPc:(R%) Pentacene(30nm)/ C60(40nm)/BCP(10nm)/ Al(100nm)。我們調變了在5%的摻雜濃度下並獲致優異之太陽能電池特性，包括:短路電流高達7.74 mA/cm2，開路電壓為0.5 V，填充因數為44.3 %，及效率為1.72 %。

In this thesis, we demonstrate a single heterojunction organic photovoltaic (OPV) cell using wide-bandgap electron-blocking layer, which can improve photocurrent absorption efficiency, balance carrier mobility between acceptor and donor can affect the carrier collection efficiency, and enhance the short-circuit current (JSC) , open-circuit voltage (VOC) and the efficiency. At first, we try to optimize the best structure in OPV cells whose layer in order as glass/ITO/CuPc (X nm)/C60 (Y nm)/BCP (10 nm)/Al (100 nm), and then modulate the thickness of CuPc (electron donor layer) X and C60 (electron acceptor layer) Y to get the highest power conversion efficiency of this structure, which are 0.4 V of open-circuit voltage (VOC), 3.96 mA/cm2 of short-circuit current density (JSC), 63.1% of fill factor (FF), and 1.00% of power conversion efficiency (PCE). Secondly, We choose three wide-bandgap materials as electron-blocking layer, including ( 1 ) 4, 4', 4"- tris - ( 2 - methylphenyl phenylamino ) triphenylamine ( m-MTDATA ) ( 2 ) MeO-TPD, and (3) Ir(ppz)3, and try to modulate the thickness of electron-blocking layer to optimize the best properties, including photo-current density and open circuit voltage. The structure can reduced electron - hole recombination of OPV cell is ITO / electron-blocking layer / CuPc(X nm) / C60 (Y nm)/ BCP(10nm) / Al(100nm). The optimal thickness is m-MTDATA (4 nm); MeO-TPD (3 nm); and Ir(ppz)3 (0.5 nm), respectively. Finally, we choose the best performance material, m-MTDATA, as an electron-blocking layer. In additional, we doping pentacene into electron donor layer to enhance the mobility of CuPc. By the increasing of concentration on pentacene, we also find short-circuit current density (JSC ) and power conversion efficiency (PCE) were increased dramatically. This structure whose layer in order as ITO/CuPc:(R%) Pentacene (30nm)/C60 (40nm)/ BCP (10nm)/ Al (100nm). We tune concentration of Pentacene around 5% in CuPc to acquire excellent characteristics of OPV cell, including: 7.74 mA/cm2 of short-circuit current, 0.5 V of open-circuit voltage, 44.3% of fill factor, and 1.72% of efficiency.