A novel silver-doped nickel oxide hole-selective contact for crystalline silicon heterojunction solar cells

Abstract

Based on its band alignment, p-type nickel oxide (NiO_x) is an excellent candidate material for hole transport layers in crystalline silicon heterojunction solar cells, as it has a small ΔE_V and large ΔE_C with crystalline silicon. Herein, to overcome the poor hole selectivity of stoichiometric NiO_x due to its low carrier concentration and conductivity, silver-doped nickel oxide (NiO_x:Ag) hole transport layers with high carrier concentrations were prepared by co-sputtering high-purity silver sheets and pure NiO_x targets. The improved electrical conductivity of NiO_x was attributed to the holes generated by the Ag⁺ substituents for Ni²⁺, and moreover, the introduction of Ag⁺ also increased the amount of Ni³⁺ present, both of which increased the carrier concentration in NiO_x. Ag⁺ doping also reduced the c-Si/NiO_x contact resistivity and improved the hole-selective contact with NiO_x. Furthermore, the problems of particle clusters and interfacial defects on the surfaces of NiO_x:Ag films were solved by UV-ozone oxidation and high-temperature annealing, which facilitated separation and transport of carriers at the c-Si/NiO_x interface. The constructed c-Si/NiO_x:Ag solar cell exhibited an increase in open-circuit voltage from 490 to 596 mV and achieved a conversion efficiency of 14.4%.

Graphical abstract

Keywords

band alignment / nickel oxide / hole transport layer / silver-doped nickel oxide / UV-ozone

References

[1] Nie S , Chen C , Zhu C . Advanced biomass materials: progress in the applications for energy, environmental, and emerging fields. Frontiers of Chemical Science and Engineering, 2023, 17(7): 795–797

[2] Hanak D P , Manovic V . Linking renewables and fossil fuels with carbon capture via energy storage for a sustainable energy future. Frontiers of Chemical Science and Engineering, 2020, 14(3): 453–459

[3] Santos M P , Hanak D P . Carbon capture for decarbonisation of energy-intensive industries: a comparative review of techno-economic feasibility of solid looping cycles. Frontiers of Chemical Science and Engineering, 2022, 16(9): 1291–1317

[4] Liu F , Lai Y , Zhao B , Bradley R , Wu W . Photothermal materials for efficient solar powered steam generation. Frontiers of Chemical Science and Engineering, 2019, 13(4): 636–653

[5] Wang X , Zhang Z , Guo Z , Su C , Sun L . Energy structure transformation in the context of carbon neutralization: evolutionary game analysis based on inclusive development of coal and clean energy. Journal of Cleaner Production, 2023, 398: 136626

[6] Atsu D , Seres I , Farkas I . The state of solar PV and performance analysis of different PV technologies grid-connected installations in Hungary. Renewable & Sustainable Energy Reviews, 2021, 141: 110808

[7] Jaxa-Rozen M , Trutnevyte E . Sources of uncertainty in long-term global scenarios of solar photovoltaic technology. Nature Climate Change, 2021, 11(3): 266–273

[8] Phong Pham D , Kim S , Dao V A , Kim Y , Yi J . Quantum-well passivating contact at polysilicon/crystalline silicon interface for crystalline silicon solar cells. Chemical Engineering Journal, 2022, 449: 137835

[9] Li L , Ying L , Lin Y , Li X , Zhou X , Du G , Gao Y , Liu W , Lu L , Wang J . . Effective hydrogenation strategies to boost efficiency over 20% for crystalline silicon solar cell with Al₂O₃/Cu₂O passivating contact. Advanced Functional Materials, 2022, 32(43): 2207158

[10] Ballif C , Haug F J , Boccard M , Verlinden P J , Hahn G . Status and perspectives of crystalline silicon photovoltaics in research and industry. Nature Reviews Materials, 2022, 7(8): 597–616

[11] Liu Y , Li Y , Wu Y , Yang G , Mazzarella L , Procel-Moya P , Tamboli A C , Weber K , Boccard M , Isabella O . . High-efficiency silicon heterojunction solar cells: materials, devices and applications. Materials Science and Engineering R Reports, 2020, 142: 100579

[12] Essig S , Dréon J , Rucavado E , Mews M , Koida T , Boccard M , Werner J , Geissbuhler J , Löper P , Morales-Masis M . . Toward annealing-stable molybdenum-oxide-based hole-selective contacts for silicon photovoltaics. Solar RRL, 2018, 2(4): 1700227

[13] Li L , Du G , Lin Y , Zhou X , Gu Z , Lu L , Liu W , Huang J , Wang J , Yang L . . NiO_x/MoO_x bilayer as an efficient hole-selective contact in crystalline silicon solar cells. Cell Reports. Physical Science, 2021, 2(12): 100684

[14] Le A H T , Dréon J , Michel J I , Boccard M , Bullock J , Borojevic N , Hameiri Z . Temperature-dependent performance of silicon heterojunction solar cells with transition-metal-oxide-based selective contacts. Progress in Photovoltaics: Research and Applications, 2022, 30(8): 981–993

[15] Lu C , Rusli A B , Prakoso H . Hole selective WO_x and V₂O_x contacts using solution process for silicon solar cells application. Materials Chemistry and Physics, 2021, 273: 125101

[16] Liu Z , Lin W , Chen Z , Chen D , Chen Y , Shen H , Liang Z . Enhanced hole extraction of WO_x/V₂O_x dopant-free contact for p-type silicon solar cell. Advanced Materials Interfaces, 2022, 9(10): 2102374

[17] Dréon J , Jeangros Q , Cattin J , Haschke J , Antognini L , Ballif C , Boccard M . 23.5%-efficient silicon heterojunction silicon solar cell using molybdenum oxide as hole-selective contact. Nano Energy, 2020, 70: 104495

[18] Yang X , Xu H , Liu W , Bi Q , Xu L , Kang J , Hedhili M N , Sun B , Zhang X , De Wolf S . Atomic layer deposition of vanadium oxide as hole-selective contact for crystalline silicon solar cells. Advanced Electronic Materials, 2020, 6(8): 2000467

[19] Yang X , Liu W , Chen J , Sun Y . On the annealing-induced enhancement of the interface properties of NiO:Cu/wet-SiO_x/n-Si tunnelling junction solar cells. Applied Physics Letters, 2018, 112(17): 173904

[20] Wang F , Duan H , Li X , Yang S , Han D , Yang L , Fan L , Liu H , Yang J , Rosei F . Gradient doped nickel oxide hole selective heterocontact and ultrathin passivation for silicon photovoltaics with efficiencies beyond 20%. Chemical Engineering Journal, 2022, 450: 138060

[21] Liu Y , Zhu J , Cai L , Yao Z , Duan C , Zhao Z , Zhao C , Mai W . Solution-processed high-quality Cu₂O thin films as hole transport layers for pushing the conversion efficiency limit of Cu₂O/Si heterojunction solar cells. Solar RRL, 2020, 4(1): 1900339

[22] Pan L , Liu C , Zhu H , Wan M , Li Y , Mai Y . Fine modification of reactively sputtered NiO_x hole transport layer for application in all-inorganic CsPbI₂Br perovskite solar cells. Solar Energy, 2020, 196: 521–529

[23] Du M , Zhao S , Duan L , Cao Y , Wang H , Sun Y , Wang L , Zhu X , Feng J , Liu L . . Surface redox engineering of vacuum-deposited NiO_x for top-performance perovskite solar cells and modules. Joule, 2022, 6(8): 1931–1943

[24] Li L , Zhang X , Zeng H , Zheng X , Zhao Y , Luo Y , Liu F , Li X . Thermally-stable and highly-efficient bi-layered NiO_x-based inverted planar perovskite solar cells by employing a p-type organic semiconductor. Chemical Engineering Journal, 2022, 443: 136405

[25] Chen D , Liu Z , Zhou M , Wu P , Wei J . Enhanced photoelectrochemical water splitting performance of α-Fe₂O₃ nanostructures modified with Sb₂S₃ and cobalt phosphate. Journal of Alloys and Compounds, 2018, 742: 918–927

[26] Zhang W , Shen H , Yin M , Lu L , Xu B , Li D . Heterostructure silicon solar cells with enhanced power conversion efficiency based on SiO_x/Ni³⁺ self-doped NiO_x passivating contact. ACS Omega, 2022, 7(19): 16494–16501

[27] Bertrandie J , Han J , De Castro C S P , Yengel E , Gorenflot J , Anthopoulos T , Laquai F , Sharma A , Baran D . The energy level conundrum of organic semiconductors in solar cells. Advanced Materials, 2022, 34(35): 2202575

Competing interests

The authors declare that they have no competing interests.

Acknowledgements

This work is supported by the National Natural Science Foundation of China (Grant No. 61974076), and the China National Key R&D Program (Grant No. 2022YFC2807104).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11705-024-2384-6 and is accessible for authorized users.

RIGHTS & PERMISSIONS

2024 Higher Education Press