TY - GEN
T1 - From Femtoseconds to Gigaseconds
T2 - 48th IEEE Photovoltaic Specialists Conference, PVSC 2021
AU - Unruh, Davis G.
AU - Hansen, Chase M.
AU - Meidanshahi, Reza Vatan
AU - Goodnick, Stephen
AU - Zimanyi, Gergely T.
N1 - Funding Information:
Acknowledgment Discussions with M. Bertoni and S. Manzoor are gratefully acknowledged. This work was supported by DOE SETO grant DE-EE0008979 . References
Publisher Copyright:
© 2021 IEEE.
PY - 2021/6/20
Y1 - 2021/6/20
N2 - a-Si/c-Si heterojunction solar cells hold the efficiency world record around 27%, yet their market penetration is delayed. One concern is the presence of an amorphous Si layer that some suspect may speed up the degradation of their performance. To address this concern, we developed the SolDeg structural simulation platform that is capable of capturing extremely slow degradation processes in a-Si. 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. In this paper we report SolDeg simulations for Si-only heterojunctions. The SolDeg platform enabled us to determine the defect generation rate to be in the 15-20%/year range, translating into a 1-1.5%/year Voc degradation rate. These results establish that SolDeg can be a uniquely useful platform to describe degradation processes with an eye on finding strategies to mitigate the performance degradation of these promising heterojunction cells.
AB - a-Si/c-Si heterojunction solar cells hold the efficiency world record around 27%, yet their market penetration is delayed. One concern is the presence of an amorphous Si layer that some suspect may speed up the degradation of their performance. To address this concern, we developed the SolDeg structural simulation platform that is capable of capturing extremely slow degradation processes in a-Si. 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. In this paper we report SolDeg simulations for Si-only heterojunctions. The SolDeg platform enabled us to determine the defect generation rate to be in the 15-20%/year range, translating into a 1-1.5%/year Voc degradation rate. These results establish that SolDeg can be a uniquely useful platform to describe degradation processes with an eye on finding strategies to mitigate the performance degradation of these promising heterojunction cells.
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U2 - 10.1109/PVSC43889.2021.9518604
DO - 10.1109/PVSC43889.2021.9518604
M3 - Conference contribution
AN - SCOPUS:85115921125
T3 - Conference Record of the IEEE Photovoltaic Specialists Conference
SP - 1455
EP - 1457
BT - 2021 IEEE 48th Photovoltaic Specialists Conference, PVSC 2021
PB - Institute of Electrical and Electronics Engineers Inc.
Y2 - 20 June 2021 through 25 June 2021
ER -