科研之友
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摘要
The performance of solar-cell devices is conventionally analyzed electrically by current-voltage measurements. To access the physics of the current generation process at the operating point, the analysis of fast optical responses from devices is highly beneficial. However, the optical responses from p-n junctions exhibit a complex photoluminescence (PL) decay behavior due to their time-dependent electric fields. Here, we propose a method to systematically assign the physical meanings of the PL decay time constants by recording the complete excitation power dependence and voltage dependence of the time-resolved PL from a GaAs single junction. The experimentally obtained PL curves are in agreement with numerical predictions of dominant charge separation. We conclude that the charge separation can be directly observed in state-of-the-art devices. The experimental data set enables assignment of the effective separation time constant for the maximum output power condition, which is the most important number for understanding the carrier dynamics during device operation. The technique developed in this work constitutes a contactless characterization technique for solar cells.
- 出版日期2017-1-26
