- 學位論文
太陽光譜變化對於多接面太陽能 電池特性影響之分析
Effects of Solar Spectral Variation on InGap/InGaAs/Ge Triple Junction Solar Cell Performance
摘要
高效率III-V族化合物半導體多接面太陽電池主要藉由多個子電池分別吸收不同波段的太陽光譜，以輸出比單接面太陽電池要高的電壓以及較低的電流。由於將光譜分段吸收，此種多接面太陽電池對於太陽光譜變化之反應亦較單接面太陽電池敏感，所以當計算其轉換效率時，太陽光譜的變化應該要被列入考量。此論文所敘述者係以InGaP/InGaAs/Ge三接面太陽電池為例，利用太陽模擬器分別調整在短波長(200-900 nm)和長波長(>900 nm) 的光譜強度(70-100 mW/cm2)，並將所模擬的光譜與InGaP/InGaAs/Ge三接面太陽電池的光譜響應作積分，以判斷在太陽光譜產生變化的情況下是否影響到電流限制子電池的演變以及所導致的太陽電池轉換效率變化。 結果指出，於短波長部份的光譜強度由100至70 mW/cm2的降下範圍內，造成短路電流下降達58%，而於長波長光譜強度同樣的降下範圍內只造成短路電流35%的下降，特別是，短波長光譜強度的降下甚至導致限制子電池由中間子電池轉變為頂部子電池。另一方面，開路電壓與填充因子則不隨長短波長光譜強度的改變而明顯變化。綜合上述效應，長波長光譜強度下降導致太陽能電池的轉換效率衰退約8%；而短波長光譜強度下降更造成轉換效率高達38%的掉落。
並列摘要
The high efficiency of III-V compound semiconductor multi-junction solar cells is achieved mainly by absorbing different bands of solar spectrum with their corresponding subcells to afford a higher output voltage and a lower output current than single junction ones. The influence of variations in solar spectrum on multi-junction solar cells is more evident than single-junction ones due to the separation of absorption ranges of solar spectrum for the former. It is therefore important to consider the effects of spectral variations when the performance of high-efficiency multi-junction solar cells is evaluated. In this study, we modulated the intensity of incident spectrum by a solar simulator and integrated it with the spectral response data of InGaP/(In)GaAs/Ge triple-junction solar cell to examine the corresponding responses of solar cell. It is suggested that short circuit current decayed because of the reduction of solar spectrum, which therefore resulted in the drop of the conversion efficiency of triple junction solar cell. Besides, current limiting cell was changed from middle subcell to top subcell when the solar spectrum irradiance at the short wavelength side reduced.