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Enhanced Conversion Efficiency of Monocrystalline P‐Type Passivated Emitter and Rear Cells in Commercial Production Line by Improving Rear Side Passivation
Author(s) -
Pu Tian,
Shen Honglie,
Hong Neoh Kuang,
Ye Fei,
Tang Quntao
Publication year - 2021
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202001115
Subject(s) - passivation , monocrystalline silicon , materials science , silicon nitride , silicon , refractive index , common emitter , layer (electronics) , optoelectronics , stack (abstract data type) , nitride , nanotechnology , computer science , programming language
An industrially proven method for increasing cell efficiency of monocrystalline P‐type PERC cells is reported, whereby a layer of silicon oxide or silicon oxynitride (SiO x /SiO x N y ) is sandwiched between aluminum oxide (AlO x ) and silicon nitride (SiN x ) in the rear passivation stack, forming an AlO x + SiO x /SiO x N y + SiN x structure. This additional layer will theoretically improve the rear side optical and electrical properties for the cell. By adjusting the flow ratio of N 2 O:NH 3 , SiO x /SiO x N y with different refractive indices were fabricated. Optimization of the SiO x film thickness showed a 0.11% efficiency gain in monofacial P‐type PERC cells because of higher short‐circuit current ( I sc ) and fill factor (FF), whereas optimization of the SiO x N y film refractive index showed a 0.05% efficiency gain in bifacial P‐type PERC cells due to the improvement of I sc and FF too. The current gain is believed to be benefited from the optimized light‐absorbing performance of the composite passivation layer structure. Furthermore, it is demonstrated that the refractive index of the SiN x capping layer had to be tuned after the incorporation of SiO x /SiO x N y to improve the cell efficiency.