Defects Passivation via Potassium Iodide Post-Treatment for Antimony Selenosulfide Solar Cells with Improved Performance

Antimony selenosulfide (Sb₂(S,Se)₃) has been emerging as a promising light absorber in the past few years owing to tunable bandgap (1.1–1.7 eV), high absorption coefficient (>10⁵ cm⁻¹) and excellent phase and environmental stability. However, the efficiency of Sb₂(S,Se)₃ solar cells lags far behind the Shockley–Queisser limit. One of the critical obstacles originates from various extrinsic and intrinsic defects. They mostly locate in the deep energy levels and are prone to form recombination centers, inhibiting the improvement of device performance. Herein, surface post-treatment via potassium iodide is introduced to fabricate high-quality Sb₂(S,Se)₃ films and solar cells. The surface post-treatment not only manipulates the crystal growth process to form compact films with larger grain size but also forms better band alignment and inhibits the formation of deep-level defects antimony antisite (Sb_Se), thus improving the quality of heterojunction. Consequently, the resultant Sb₂(S,Se)₃ solar cells achieve a champion power conversion efficiency  of 9.22%. This study provides a new strategy of passivating deep-level intrinsic defects via surface post-treatment for high-efficiency Sb₂(S,Se)₃ solar cells.     

不同材质水桶的使用次数对Sb和BPA渗出量的影响

选取聚对苯二甲酸乙二醇酯(PET)和聚碳酸酯(PC)两种材质,重复使用次数分别为0、5、20、40次的饮用纯净水桶,以灌装前的纯水为空白对照,采用液质联用和原子荧光法分别检测不同存放时间桶装水中双酚A(BPA)、Sb的浓度,评价两种材质水桶重复使用的次数及存放时间对有害物质渗出量的影响。结果表明,随使用次数及存放时间的延长,PET桶中的Sb浓度和PC桶中的BPA浓度具有显著增大的趋势。一般情况下,水桶重复使用次数是影响Sb和BPA渗出量的主要因素。Sb和BPA渗出量的检测值均随着存放时间及水桶的重复使用次数显著增大。在正常使用条件下,BPA浓度仍均远小于WHO、EFSA和美国EPA的建议值,在安全范围以内;但Sb浓度可能出现超出GB5749—2006《生活饮用水卫生标准》限值的情况。     

All-Vacuum-Processed Sb2(S,Se)3 Thin Film Photovoltaic Devices via Controllable Tuning Seed Orientation

Quasi-one-dimensional antimony sulfoselenide (Sb₂(S,Se)₃) semiconductor is one of the most promising light-harvesting materials owing to its simple phase and tunable absorption spectra. However, the oriented [Sb₄(S,Se)₆]_n ribbons of Sb₂(S,Se)₃ thin films nearly horizontally stacked in parallel to the substrate severely hinders the transport of carriers, yet is critical to control the absorber orientation growth for high-performance Sb₂(S,Se)₃ solar cells. Herein, a new close spaced sublimated (CSS) CdS buffer layer with high crystallization is introduced for the development of all-vacuum-processed Sb₂(S,Se)₃ solar cells that attempt to induce the orientation of Sb₂(S,Se)₃ absorbers to achieve effective carrier transport and reduce the adverse effects. The resulting Sb₂(S,Se)₃ solar cells with CSS-CdS buffer layers exhibit a prominent [221] orientation and better heterointerfaces as well as lower defect densities and longer capture lifetime compared to the commonly solar cells used chemically deposited CdS buffer layers, as a result of suppressed the non-radiative recombination. The optimized solar cells, yield up to an efficiency of 7.12%, is the first for an all-vacuum-process for Sb₂(S,Se)₃ solar cells.     

Controlling the Intermediate Phase to Improve the Crystallinity and Orientation of Cs3Sb2ClxI9-x Films for Efficient Solar Cells

Lead-free 2D antimony-based halide perovskites with excellent optoelectronic properties, low toxicity, and good intrinsic stability are promising for photovoltaic devices. However, the power conversion efficiency (PCE) of antimony-based perovskite solar cells (PSCs) is still lower than 3% due to the poor crystallinity and random orientation. Herein, it is found that the Cs₃Sb₂Cl_xI_9-x films prepared by adding methylamine chloride as an additive to the precursor solution can form a mixed intermediate phase with 0D dimer phase and 2D layered phase after low pressure treatment. During the annealing process, the 0D dimer phase will completely transition to 2D layered phase due to the partial replacement of I by Cl. Compared to adding SbCl₃ directly, this method considerably increases the crystallinity of Cs₃Sb₂I_xCl_9-x films. The obtained films have a preferential orientation along the (201) direction, which is beneficial for charge carrier transportation. Consequently, the champion device shows a PCE of 3.2%, which is one of the highest efficiencies achieved for inorganic Sb-based PSCs with the n-i-p architecture to date.