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The photovoltaic conversion efficiency of Sb2(S,Se)3 thin-film cells is significantly limited by carrier recombination at the back-contact interface. Therefore, an increasing number of studies have focused on back-contact interface optimisation. This study enhances the photovoltaic conversion efficiency of Sb2(S,Se)3 thin-film solar cells by utilizing NiOx as the hole transport layer (HTL). The inclusion of NiOx helps address the mismatch between the energy-level alignment of Sb2(S,Se)3 and the metal electrode, resulting in increased carrier collection efficiency and reduced carrier recombination at the back-contact interface, thus enhancing the performance of solar cells as a result. Under the same conditions, the NiOx film has a more suitable energy-level alignment with the Sb2(S,Se)3 film than the device fabricated with spiro-OMeTAD as the HTL, as it can extract and transport holes more efficiently and block electron transport. In addition, the influence of solution concentration and the annealing temperature on the NiOx film and device has undergone extensive investigation. The final NiOx device achieved a photovoltaic conversion efficiency of 7.40% and maintained an initial efficiency of 92% after 700 h, showing higher stability than the spiro-OMeTAD device. These findings show the enormous potential of NiOx as a hole-transport layer and offer fresh perspectives on choosing hole-transport layers for Sb2(S,Se)3 thin-film cells. [ABSTRACT FROM AUTHOR]

The efficiency of antimony selenide (Sb2Se3) solar cells is still limited by significant interface and deep‐level defects, in addition to carrier recombination at the back contact surface. This paper investigates the use of lithium (Li) ions as dopant for Sb2Se3 films, using lithium hydroxide (LiOH) as a dopant medium. Surprisingly, the LiOH solution not only reacts at the back surface of the Sb2Se3 film but also penetrate inside the film along the (Sb4Se6)n molecular chain. First, the Li ions modify the grain boundary's carrier type and create an electric field between p‐type grain interiors and n‐type grain boundary. Second, a gradient band structure is formed along the vertical direction with the diffusion of Li ions. Third, carrier collection and transport are improved at the surface between Sb2Se3 and the Au layer due to the reaction between the film and alkaline solution. Additionally, the diffusion of Li ions increases the crystallinity, orientation, surface evenness, and optical electricity. Ultimately, the efficiency of Sb2Se3 solar cells is improved to 7.57% due to the enhanced carrier extraction, transport, and collection, as well as the reduction of carrier recombination and deep defect density. This efficiency is also a record for CdS/Sb2Se3 solar cells fabricated by rapid thermal evaporation. [ABSTRACT FROM AUTHOR]

Antimony selenosulphide (Sb2(S,Se)3) has undergone rapid development recently owing to its adjustable band gap, high light-absorption coefficient and excellent optoelectronic properties as well as its safety, non-toxicity and low-cost aspects. High-efficiency Sb2(S,Se)3 thin film solar cells use Spiro-OMeTAD hollow-hole transport materials to construct n–i–p (n-type, intrinsic and p-type) structures; however, the poor stability and high cost of Spiro-OMeTAD limit its large-scale application in Sb2(S,Se)3 solar cells. Herein, in order to address these problems, we report stable and efficient Sb2(S,Se)3 solar cells enabled by various phthalocyanine hole transport layers (HTLs). The pure Pc and Sb2(S,Se)3 absorbers exhibited improved valence band alignment compared to Spiro-OMeTAD. The device with the tuning concentration of phthalocyanine solution shows high homogeneity and carrier transport. The increased hole transport capability of the Pc material facilitated a higher JSC in the Pc device, resulting in a photoelectric conversion efficiency of 8.42%. Furthermore, the Pc device maintained an initial efficiency of 97.5% after 700 h compared to the Spiro-OMeTAD-based device. These results demonstrate the great potential of the Pc hole transport layer and provide new insights into the selection of HTL materials for the preparation of highly efficient Sb2(S,Se)3 thin film solar cells. [ABSTRACT FROM AUTHOR]