Silicon based solar cells using a multilayer oxide as emitter

Abstract

In this work, n-type silicon based solar cells with WO3/Ag/WO3 multilayer films as emitter (WAW/n-Si solar cells) were presented via simple physical vapor deposition (PVD). Microstructure and composition of WAW/n-Si solar cells were studied by TEM and XPS, respectively. Furthermore, the dependence of the solar cells performances on each WO3 layer thickness was investigated. The results indicated that the bottom WO3 layer mainly induced band bending and facilitated charge-carriers separation, while the top WO3 layer degraded open-circuit voltage but actually improved optical absorption of the solar cells. The WAW/n-Si solar cells, with optimized bottom and top WO3 layer thicknesses, exhibited 5.21% efficiency on polished wafer with area of 4 cm2 under AM 1.5 condition (25 °C and 100 mW/cm2). Compared with WO3 single-layer film, WAW multilayer films demonstrated better surface passivation quality but more optical loss, while the optical loss could be effectively reduced by implementing light-trapping structures. These results pave a new way for dopant-free solar cells in terms of low-cost and facile process flow.

Recent Advances in and New Perspectives on Crystalline Silicon Solar Cells with Carrier-Selective Passivation Contacts

“…Gerling [38] and Wu [39] compared the effects of the V 2 O x , MoO x , and WO x hole-selective contacts on the SHJ solar cells, reaching a conclusion that V 2 O x is a better candidate for the hole-selective contact. Shen and co-workers proposed a multi-layered emitter (i.e., hole-selective contact) based on a TMO/Ag/TMO structure [33,81]. The first TMO layer to make contact with c-Si caused band bending on the c-Si surface, achieving carrier selectivity.…”

Dopant‐free passivating contacts for crystalline silicon solar cells: Progress and prospects

“…Meanwhile, some researchers focus on the passivating contact by employing the TMO/metal/TMO multilayer structure as an emitter, [177][178][179] which shows high conductivity and high transmittance for the front contact. 180 For example, Wu et al investigated the effect of the intermediate metal layer on the V 2 O x /metal/V 2 O x structure and found that the intermediate metal with a high W F and a thinner thickness will decrease ρ c. 181 The c-Si solar cell employing the optimized V 2 O x /4-nm Au/V 2 O x as the emitter achieves an efficiency of 19.02%, which is 1.44% higher than that of the c-Si solar cell using a single layer of V 2 O x as the emitter. Yet the poor longterm stability of the structure still needs to be resolved, and the efficiency drops by nearly 50% over 100 days.…”

MoO x /Ag/MoO x multilayers as hole transport transparent conductive electrodes for n‐type crystalline silicon solar cells

“…DMD multilayers that are deposited at room temperature and thus do not induce thermal damage to the mechanical, electrical, and optical properties of underlying layers can be optimized by changing the material types, layer thicknesses, and refractive indices without the need of post deposition texturing. Therfore, DMDs are considered as promising candidates to replace standard TCEs in solar cells . The electrical properties of DMD structures can be tuned by varying the layer thicknesses and material choice.…”

“…Therfore, DMDs are considered as promising candidates to replace standard TCEs in solar cells. [16][17][18][19] The electrical properties of DMD structures can be tuned by varying the layer thicknesses and material choice. Thus, these DMD TCEs can be fabricated with materials that come at lower cost than conventional TCEs and can be prepared by conventional deposition techniques, while achieving superior optical and electrical properties.…”