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Vol. 19 (2027)

Interface Contact Optimization via Phosphomolybdic Acid Enables 24.9% Efficiency in MoOX-Based Silicon Solar Cells

https://doi.org/10.1007/s40820-026-02250-4
Shaopeng Chen
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China
Qian Kang
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China
Xiqi Yang
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Hao Zhang
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Jingjie Li
School of Physics and Optoelectronic Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Wanyu Lu
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China
Linfeng Yang
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China
Tinghao Liu
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Dayong Yuan
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China
Zilong Zheng
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Hui Yan
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, People’s Republic of China
Yongzhe Zhang
School of Information Science and Technology, Key Laboratory Optoelectronics Technology Ministry of Education, Beijing University of Technology, Beijing 100124, People’s Republic of China

Corresponding Author: Yongzhe Zhang

yzzhang@bjut.edu.cn

Nano-Micro Letters, Vol. 19 (2027), Article Number: 16

Abstract

The development of cost-effective carrier-selective passivating contacts is critical for enhancing the commercial feasibility of silicon compound solar cells. Molybdenum oxide (MoOX) has garnered considerable interest as a promising hole transport layer (HTLs). A key advantage of MoOX is high work function, in addition to the low-cost processability. However, in silicon photovoltaics, MoOX-based p-type contacts face fundamental limitations at hydrogenated amorphous silicon (i-a-Si:H)/MoOX interface, where oxygen vacancy defects lower work function, as well as, weak van der Waals-dominated interactions impair charge carry transport. To address these challenges, we introduced an ultrathin phosphomolybdic acid (PMA) interlayer at the i-a-Si:H/MoOX interface. PMA passivated oxygen vacancy defects, resulting in a notable improvement in open-circuit voltage from 713 to 730 mV, and 0.11 eV work function elevation via dipole formation; meanwhile, PMA strengthened the interfacial bonding energy, reducing saturation current density and contact resistance by 63% and 24%, respectively, contributing to a fill factor enhancement from 83.7% to 84.9%. In the end, we demonstrated a record efficiency of 24.9% for MoOX-based silicon solar cells, which provides valuable insights for developing high-performance MoOX HTL devices for dopant-free p-type contact technologies.


Highlights:
1 We present a novel phosphomolybdic acid (PMA)/MoOX that overcomes the intrinsic passivation and transport limitations of transition metal oxides in silicon photovoltaics.
2 PMA acts as a dual-functional modifier, creating a strong interface dipole (6.34 D) and reducing the tunneling barrier, which lowers the contact resistance by 24%.
3 The optimized dopant-free contact achieves a record-breaking efficiency of 24.9%, high-performance silicon solar cells.

Keywords

Interface engineering Passivation Silicon compound solar cells MoOX Hole transport layers
Chen, Shaopeng, Qian Kang, Xiqi Yang, Hao Zhang, Jingjie Li, Wanyu Lu, Linfeng Yang, Tinghao Liu, Dayong Yuan, Zilong Zheng, Hui Yan, and Yongzhe Zhang. 2026. “Interface Contact Optimization via Phosphomolybdic Acid Enables 24.9% Efficiency in MoOX-Based Silicon Solar Cells”. Nano-Micro Letters 19 (July):16. https://doi.org/10.1007/s40820-026-02250-4.
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