High-Performance Gridless and Flexible Crystalline Silicon Heterojunction Solar Cells with MoO_<i>x</i>/Patterned Ultrathin Silver Hole-selective Contacts

Distinct MoOx-based hole-selective contacts (HSCs) are presented, where sparsely and densely patterned Ag (sp- and dp-Ag) ultrathin films are deposited on the MoOx layer. Through patterning the Ag film, the solar transmissivity is improved by 37.24 and 25.74% for the MoOx/sp-Ag and MoOx/dp-Ag HSCs, respectively, which also show excellent contact performances on n-type crystalline silicon (c-Si) with their contact resistivities much lower than those of reported MoOx-based HSCs. Based on our HSCs, 200 μm-thick c-Si heterojunction solar cells are over 32% more efficient than their counterparts with the MoOx/unpatterned Ag HSCs. Due to the good carrier collection ability, when the inner grid of the top electrode is removed, the efficiencies of the gridless solar cells are enhanced further, and the cell with the MoOx/dp-Ag HSC achieves the maximal efficiency of 10.9%. When the thickness is reduced to merely 17.5% of its initial value, the gridless solar cells with MoOx/patterned-Ag HSCs are still over 86% efficient. In addition, over 92% of the efficiency can be maintained even when they are bent to a radius as small as 4 mm, showing extraordinary mechanical flexibility. We believe that our designs are promising for cost-effective and flexible c-Si renewable power sources.