摘要
Tunnel oxide passivated contact solar cells have evolved into one of the most promising silicon solar cell concepts of the past decade,achieving a record efficiency of 25%.We study the transport mechanisms of realistic tunnel oxide structures,as encountered in tunnel oxide passivating contact(TOPCon) solar cells.Tunneling transport is affected by various factors,including oxide layer thickness,hydrogen passivation,and oxygen vacancies.When the thickness of the tunnel oxide layer increases,a faster decline of conductivity is obtained computationally than that observed experimentally.Direct tunneling seems not to explain the transport characteristics of tunnel oxide contacts.Indeed,it can be shown that recombination of multiple oxygen defects in a-SiOx can generate atomic silicon nanowires in the tunnel layer.Accordingly,new and energetically favorable transmission channels are generated,which dramatically increase the total current,and could provide an explanation for our experimental results.Our work proves that hydrogenated silicon oxide(SiOx:H) facilitates high-quality passivation,and features good electrical conductivity,making it a promising hydrogenation material for TOPCon solar cells.By carefully selecting the experimental conditions for tuning the SiOx:H layer,we anticipate the simultaneous achievement of high open-circuit voltage and low contact resistance.
作者
李峰
端伟元
Manuel Pomaska
Malte Köhler
丁凯宁
普勇
Urs Aeberhard
Uwe Rau
Feng Li;Weiyuan Duan;Manuel Pomaska;Malte Köhler;Kaining Ding;Yong Pu;Urs Aeberhard;Uwe Rau(College of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;IEK-5 Photovoltaik,Forschungszentrum Jülich,52425 Jülich,Germany)
基金
Supported by the National Natural Science Foundation of China(Grant Nos.61704083 and 61874060)
the Natural Science Foundation of Jiangsu Province(Grant No.BK20181388)
NUPTSF(Grant No.NY219030)。