TY - GEN
T1 - Machine Learning Driven Studies of Performance Degradation in a-Si:H/c-Si Heterojunction Solar Cells
AU - Unruh, Davis
AU - Meidanshahi, Reza Vatan
AU - Hansen, Chase
AU - Goodnick, Stephen M.
AU - Zimanyi, Gergely T.
N1 - Funding Information:
Funded by the DOE SETO grant DE-EE0008979
Funding Information:
We thank Mariana Bertoni, and Salman Manzoor for many fruitful discussions.
Publisher Copyright:
© 2021 IEEE.
PY - 2021/6/20
Y1 - 2021/6/20
N2 - a-Si:H/c-Si heterojunction solar cells hold the efficiency world record around 27%, yet their market penetration is delayed. One concern is the migration of passivating hydrogen away from the interface, that some suspect may speed up the degradation of their performance. Mitigating the performance degradation necessitates the understanding of the structural evolution of a-Si:H/c-Si structures, with a focus on hydrogen migration. To this end, we have developed the SolDeg structural simulation platform that is capable of capturing extremely slow degradation processes. SolDeg integrates molecular dynamics methods that optimize the Si structure with femtosecond time steps, with the nudged elastic band method that captures the defect generation on time scales extending to gigaseconds. The molecular dynamics layer of SolDeg requires a high quality Si-H interatomic potential. While classical parametric interatomic potentials have been used extensively, the recent development of machine-learning driven interatomic potentials ignited the ambition of achieving DFT-level accuracy with classical molecular dynamics simulations. In this paper we report the development of the first machine-learning driven Gaussian Approximation Potential (GAP) to describe Si-H interactions. This potential will be used in the SolDeg platform to determine the performance degradation of a-Si:H/c-Si heterojunction solar cells.
AB - a-Si:H/c-Si heterojunction solar cells hold the efficiency world record around 27%, yet their market penetration is delayed. One concern is the migration of passivating hydrogen away from the interface, that some suspect may speed up the degradation of their performance. Mitigating the performance degradation necessitates the understanding of the structural evolution of a-Si:H/c-Si structures, with a focus on hydrogen migration. To this end, we have developed the SolDeg structural simulation platform that is capable of capturing extremely slow degradation processes. SolDeg integrates molecular dynamics methods that optimize the Si structure with femtosecond time steps, with the nudged elastic band method that captures the defect generation on time scales extending to gigaseconds. The molecular dynamics layer of SolDeg requires a high quality Si-H interatomic potential. While classical parametric interatomic potentials have been used extensively, the recent development of machine-learning driven interatomic potentials ignited the ambition of achieving DFT-level accuracy with classical molecular dynamics simulations. In this paper we report the development of the first machine-learning driven Gaussian Approximation Potential (GAP) to describe Si-H interactions. This potential will be used in the SolDeg platform to determine the performance degradation of a-Si:H/c-Si heterojunction solar cells.
KW - degradation
KW - machine learning
KW - molecular dynamics
KW - silicon heterojunctions
UR - http://www.scopus.com/inward/record.url?scp=85115974687&partnerID=8YFLogxK
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U2 - 10.1109/PVSC43889.2021.9519018
DO - 10.1109/PVSC43889.2021.9519018
M3 - Conference contribution
AN - SCOPUS:85115974687
T3 - Conference Record of the IEEE Photovoltaic Specialists Conference
SP - 1600
EP - 1602
BT - 2021 IEEE 48th Photovoltaic Specialists Conference, PVSC 2021
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 48th IEEE Photovoltaic Specialists Conference, PVSC 2021
Y2 - 20 June 2021 through 25 June 2021
ER -