Molten Salts Assisted Interfacial Engineering for Efficient and Low‐Cost Full‐Inorganic Antimony Sulfide Solar Cells

• Published in: Advanced functional materials Vol. 32; no. 48
• Main Authors: Mao, Yu, Hu, Yi‐Hua, Hu, Xiao‐Yang, Yao, Li‐Quan, Li, Hu, Lin, Li‐Mei, Tang, Peng, Li, Hui, Chen, Shuiyuan, Li, Jian‐Min, Chen, Gui‐Lin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.11.2022
• Subjects: Circuits; Doping; Energy conversion efficiency; full‐inorganic solar cells; interfacial engineering; Li doping; Lithium; Materials science; molten salt method; Molten salts; Performance enhancement; Photoelectricity; Photovoltaic cells; Sb 2S 3 solar cell; Solar cells; Thin films; Valence band
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202208409

Antimony sulfide (Sb2S3) is emerging as a promising light harvesting material owing to its brilliant photoelectric property. However, the performance of Sb2S3‐based solar cells is partly limited by serious back contact interface recombination and hole transportation resistance. High‐efficiency Sb2S3 devices typically use Spiro‐OMeTAD and/or Au as back contact materials, but their stability and cost are a concern. In this sense, a surface modification scheme by lithium‐doping is first introduced for Sb2S3 via a facile molten salt method. The ions in the molten state have high mobility and activity, enabling doping reactions to complete within a short time. The lithium‐doped Sb2S3 thin film has a smooth and well‐bonded surface, preferred (hk1) orientations, and an upshifted valence band maximum (VBM), which favors the hole extraction. Finally, a device using carbon as an electrode, which is more than a dozen times cheaper than gold, raises the short‐circuit current density (JSC) from 12.35 to 14.40 mA cm−2, and the power conversion efficiency (PCE) from 4.47% to 6.16%. This is among the highest PCE reported for full‐inorganic Sb2S3 solar cells, which demonstrates a facile interface modification technique via molten alkali salt to improve the performance of Sb2S3 solar cells. Sb2S3 is a kind of new light‐absorbing material possessing high stability in ambient environment, high absorption coefficient in the visible range, and abundant elemental storage. Here, a surface modification scheme by lithium‐doping is first introduced for Sb2S3 via a facile molten salt method. The device with the low‐cost carbon electrode delivers a power conversion efficiency (PCE) of 6.16%, which is among the highest PCE reported for the full‐inorganic Sb2S3 solar cells.