A Robust Hydrothermal Sulfuration Strategy toward Effective Defect Passivation Enabling 6.92% Efficiency Sb₂S₃ Solar Cells

Abstract

Chalcogenide-based solar cells, such as Cu(In,Ga)(S,Se) 2 (CIGSSe), [1] CdTe, [2] Cu 2 ZnSn(S,Se) 4 (CZTSSe), [3,4] CuSb(S, Se) 2 , [5] NaSbS 2 , [6] AgBiS 2 , [7] SnS, [8] GeSe, [9] and Sb 2 (S,Se) 3 , [10,11] are emerging photovoltaic systems with great application potential. Currently, the record efficiencies of CIGSSe and CdTe photovoltaic devices are over 22%. [12] Furthermore, the certified efficiencies of CZTSSe [3] and Sb 2 (S,Se) 3 [13] solar cells have achieved ≥10% efficiencies. Besides, CZTS [14,15] and Sb 2 S 3 [16] have shown a bright application prospect because it does not contain the relatively rare and relatively expensive Se. In particular, it should be pointed out that Sb 2 S 3 solar cell has attracted extensive attention, due to its advantages of large absorption coefficient, suitable bandgap, earth-abundant, and nontoxic compositions. [17][18][19] However, the device performance of Sb 2 S 3 solar cell is still seriously limited by anion-vacancy-induced defects (i.e., V S and Sb S ) that make it obviously lower than the Sb 2 Se 3 or Sb 2 (S,Se) 3 photovoltaic devices. [20][21][22][23] Therefore, developing a mild, efficient, and low-cost method to suppress sulfur-vacancy-induced defects is an important solution to improve the device performances of Sb 2 S 3 solar cells.Currently, sulfuration is an efficient approach to passivate V S and Sb S defects of Sb 2 S 3 absorber layers due to its significant role in improving the content of S. There are five types of sulfur sources that have been reported to treat Sb 2 S 3 and CZTSSe absorber layers: elemental sulfur, [24] H 2 S, [25] thiourea (TU), [26,27] thioacetamide (TA), [28] and ammonium sulfide ((NH 4 ) 2 S). [29] Massspectrometric results have indicated that the presence of all possible S n molecules between S 2 and S 8 in measurable concentration between room temperature and the boiling point of sulfur (444.6 °C). [30] In addition, the highly active S 2 can only be guaranteed in large quantities at high temperatures, but Sb 2 S 3 cannot tolerate such annealing temperatures due to low melting point (550 °C), which makes it difficult to effectively passivate the defects in Sb 2 S 3 using elemental sulfur. At present, H 2 S sulfuration is the most efficient sulfuration method, but its high toxicity and corrosiveness greatly increase the complexity and danger. [25] Essentially, the sulfuration processes using TU, TA,

Negative-pressure sulfurization of antimony sulfide thin films for generating a record open-circuit voltage of 805 mV in solar cell applications

“…This result indicated that the Sb 2 S 3 -S-TF device had a reduced probability of charge recombination and improved efficiency of charge transfer, improving the photovoltaic performance of the device. 57…”

A comprehensive insight into deep-level defect engineering in antimony chalcogenide solar cells

“…Huang et al 77 demonstrated a novel (NH 4 ) 2 S-induced hydrothermal sulfurization process for the fabrication of Sb 2 S 3 solar cells. (NH 4 ) 2 S undergoes hydrolysis to produce H 2 S, a strong sulfurization agent.…”

“…96 However, recent studies suggest that controlled O 2 -incorporation can help in passivating bulk and interface defects, improving the device performance. 97 In addition, in situ sulfurization, 98,99 post-deposition thioacetamide (TA) treatment, 78 ammonium sulfide ((NH 4 ) 2 S) treatment, 77 thiourea (TU) treatment, 5 selenization, 100–102 alkali-metal doping, 103–105 and alcohol-vapor annealing 106 are key strategies to passivate deep-defects and boost the PCE of Sb 2 X 3 solar cells.…”

Bulk Defect Passivation for Full‐Inorganic Sb2S3 Solar Cells by Sulfur‐Atmosphere Recrystallization Process

“…[31] Huang et al introduced tartaric acid additives in the hydrothermal deposition process of Sb 2 S 3 to achieve in situ sulfurization and optimized the hydrothermal sulfurization process by using (NH 4 ) 2 S, achieving efficiencies of 6.31 and 6.92%, respectively. [32,33] Zeng et al manufactured Sb 2 S 3 films from a raw stibnite source and removed surficial oxides by the sulfurization process. [34] At present, it is reported that the sulfur sources used to treat Sb 2 S 3 absorbers include sulfur powder, thioacetamide (TA), H 2 S, thiourea (TU), and ammonium sulfide ((NH 4 ) 2 S).…”

“…[34] At present, it is reported that the sulfur sources used to treat Sb 2 S 3 absorbers include sulfur powder, thioacetamide (TA), H 2 S, thiourea (TU), and ammonium sulfide ((NH 4 ) 2 S). [31][32][33][35][36][37][38] Surface sulfurization and selenization can improve the back interfacial quality and fill factor, [35,39] which mainly acting on the surface. However, the S element makes it difficult to enter the bulk of crystalized Sb 2 S 3 films by surface sulfurization.…”