NiOx/MoOx bilayer as an efficient hole-selective contact in crystalline silicon solar cells

Abstract

Designing effective carrier-selective contact is a prerequisite for high-efficiency crystalline silicon ( c -Si) solar cells. Compared to doped silicon thin films, wide-band-gap transition metal oxides (TMOs) feature low parasitic absorption, but their carrier selectivity and passivation being poor leads to a mediocre cell efficiency. Herein, we introduce a NiO x /MoO x bilayer as an efficient hole-selective contact in c -Si solar cells. A power conversion efficiency (PCE) of 21.31% is achieved using NiO x /MoO x bilayer, outperforming cells with a single layer of NiO x or MoO x . Upon depositing NiO x on MoO x , interfacial reactions modify the stoichiometry and defect chemistry in both oxides, leading to a band alignment beneficial for hole selectivity. By inserting a SiO x tunneling layer on c -Si surface to further suppress recombination, we achieve a PCE of 21.60% (fill factor 83.34%). Our work highlights a promising approach to improve the performance of dopant-free c -Si solar cells by employing cost-effective TMOs as hole-selective contact. A NiO x /MoO x bilayer as an efficient hole-selective contact in p -Si solar cells Interfacial reaction of NiO x /MoO x modifies doping thus band alignment p -Si solar cells with NiO x/ MoO x bilayer show efficiency of 21.31% Inserting an ultra-thin SiO x tunneling layer boosts to an efficiency of 21.60% Li et al. report a NiO x /MoO x bilayer as an efficient hole-selective contact in p -Si heterojunction solar cells, delivering an efficiency of 21.31%. Inserting an additional ultra-thin SiO x tunneling layer further boosts open-circuit voltage and fill factor, resulting in an efficiency of 21.60%. This work provides a design strategy to push forward the development of c -Si solar cells with transition metal oxides as hole-selective contact.