置入量子點於p-i-n太陽能電池中以提升能量轉換效率

Abstract

本論文提出置放量子點於p-i-n 二極體中的本質層，來實現高效率太陽能電池。在選擇適當的量子點材料、量子點尺寸與置入比例下，可於原背景材料的價電帶與傳導帶之間生成一個新的中間能帶，其能階位置由上述條件決定。此一中間能帶可幫助材料吸收不足以跨過原本背景材料之能隙而無法被吸收的入射光子。 本論文先以背景材料及一般p-i-n 架構所能達到的最高能量轉換效率為基準，再置入量子點後以提升轉換效率。本論文中使用砷化鎵為背景材料，使用砷化銦為量子點材料。在選擇適當的參數與更密集的量子點排列下，本論文進一步改善具有同類架構的太陽能電池之能量轉換效率。

A model of solar cell embedding quantum dots in the intrinsic layer of a p-i-n solar cell has been presented. With proper selection of material, size and fractional volume, quantum dots can provide an intermediate band between the valence and the conduction bands of the matrix material, which will absorb photons with energy lower than the original bandgap to absorb more incident photons in the otherwise unsed spectral irradiance. The design approach to acquire the highest efficiency of the conventional p-i-n solar cell is presented as a benchmark. Quantum dots are then embedded in the intrinsic region of the reference solar cell to improve its efficiency. InAs is chosen to implement the quantum dots, to be embedded in the p-i-n solar cell made of GaAs. With a more packed arrangement of QD’s from that in the literatures, the simulation results shows that the efficiency of the conventional GaAs p-i-n solar cell can be increased by 1.05%.