A Generalized Theory Explains the Anomalous Suns– $V_{{ m{oc}}}$ Response of Si Heterojunction Solar Cells
A Generalized Theory Explains the Anomalous Suns– $V_{{
m{oc}}}$ Response of Si Heterojunction Solar Cells
复制标题
广义理论解释了异常太阳——硅异质结太阳能电池的 $V_{{ m{oc}}}$ 响应
DOI：
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发表时间：
2017
影响因子：
3
通讯作者：
M. Alam
中科院分区：
文献类型：
--
作者：
R. Chavali;Jian V. Li;C. Battaglia;S. De Wolf;J. Gray;M. Alam
Suns-Voc measurements exclude parasitic series resistance effects and are, therefore, frequently used to study the intrinsic potential of a given photovoltaic technology. However, when applied to a-Si/c-Si heterojunction (SHJ) solar cells, the Suns-Voc curves often feature a peculiar turnaround at high illumination intensities. Generally, this turn-around is attributed to extrinsic Schottky contacts that should disappear with process improvement. In this paper, we demonstrate that this voltage turnaround may be an intrinsic feature of SHJ solar cells, arising from the heterojunction (HJ), as well as its associated carrier-transport barriers, inherent to SHJ devices. We use numerical simulations to explore the full current-voltage (J-V) characteristics under different illumination and ambient temperature conditions. Using these characteristics, we establish the voltage and illumination-intensity bias, as well as temperature conditions necessary to observe the voltage turnaround in these cells. We validate our turnaround hypothesis using an extensive set of experiments on a high-efficiency SHJ solar cell and a molybdenum oxide (MoOx) based hole collector HJ solar cell. Our work consolidates Suns-Voc as a powerful characterization tool for extracting the cell parameters that limit efficiency in HJ devices.
