Lithography-free and dopant-free back-contact silicon heterojunction solar cells with solution-processed TiO2 as the efficient electron selective layer

• Published in: Solar energy materials and solar cells 2019-12, Vol.203, p.110196, Article 110196
• Main Authors: Li, Fengchao, Sun, Zongheng, Zhou, Yurong, Wang, Qi, Zhang, Qunfang, Dong, Gangqiang, Liu, Fengzhen, Fan, Zhenjun, Liu, Zhenghao, Cai, Zhengxiong, Zhou, Yuqin, Yu, Donghong
• Format: Article
• Language: English
• Subjects: Amorphous silicon; Back-contact; Dopant-free; Dopants; Heterojunction; Heterojunctions; Lithography; Lithography-free; Organic chemistry; Oxides; Passivation; Passivity; Photolithography; Photovoltaic cells; Plasma enhanced chemical vapor deposition; Silicon; Solar cells; Spin coating; Sublimation; Technology; Thickness; Titanium dioxide; Transport
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2019.110196

Lithography-free interdigitated back-contact silicon heterojunction (IBC-SHJ) solar cells with dopant-free metal oxides (TiO2 and MoOx) as the carriers selective transport layers were investigated. Spin-coating and hot-wire reactive-sublimation deposition together with low cost mask technology were used to fabricate the solar cells. Insertion of a SiOx layer with the thickness of about 2.4 nm between the intrinsic amorphous Si (a-Si:H(i)) passivation layer and the spin-coated TiO2 layer greatly improves the solar cell performance due to the enhanced field-effect passivation of the a-Si:H(i)/SiOx/TiO2 layer stack. Efficiency up to 20.24% was achieved on the lithography-free and dopant-free IBC-SHJ devices with a-Si:H(i)/SiOx/TiO2 layer stack as the electron selective transport layer, a-Si:H(i)/MoOx as the hole selective transport layer, and WOx as the antireflection layer. The novel IBC-SHJ solar cells show significant advantages in simplification of the technology and process compared with the IBC-SHJ devices whose back surface pattering and carrier selective layers relied on photolithography and plasma enhanced chemical vapor deposition (PECVD). •An a-Si:H(i)/SiOx/TiO2 layer stack was used as the efficient electron selective transport layer with spin-coated TiO2.•The hot-wire reactive-sublimation deposited MoOxwas used as the hole selective transport layer.•An efficiency of 20.24% is finally achieved on a lithography-free back-contact SHJ device.