# A generalized theory explains the anomalous suns- VOC response of si heterojunction solar cells

Raghu Vamsi Krishna Chavali, Jian V. Li, Corsin Battaglia, Stefaan De Wolf, Jeffery Lynn Gray, Muhammad Ashraful Alam

23 引文 斯高帕斯（Scopus）

## 摘要

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- $V{{\rm{oc}}}$ as a powerful characterization tool for extracting the cell parameters that limit efficiency in HJ devices.

原文 English 7756368 169-176 8 IEEE Journal of Photovoltaics 7 1 https://doi.org/10.1109/JPHOTOV.2016.2621346 Published - 2017 一月

• 電子、光磁材料
• 凝聚態物理學
• 電氣與電子工程