Precursor Engineering of Solution-Processed Sb2 S3 Solar Cells.

Antimony-based chalcogenides have emerged as promising candidates for next-generation thin film photovoltaics. Particularly, binary Sb2 S3 thin films have exhibited great potential for optoelectronic applications, due to the facile and low-cost fabrication, simple composition, decent charge transport and superior stability. However, most of the reported efficient Sb2 S3 solar cells are realized based on chemical bath deposition and hydrothermal methods, which require large amount of solution and are normally very time-consuming. In this work, Ag ions are introduced within the Sb2 S3 sol-gel precursors, and effectively modulated the crystallization and charge transport properties of Sb2 S3 . The crystallinity of the Sb2 S3 crystal grains are enhanced and the charge carrier mobility is increased, which resulted improved charge collection efficiency and reduced charge recombination losses, reflected by the greatly improved fill factor and open-circuit voltage of the Ag incorporated Sb2 S3 solar cells. The champion devices reached a record high power conversion efficiency of 7.73% (with antireflection coating), which is comparable with the best photovoltaic performance of Sb2 S3 solar cells achieved based on chemical bath deposition and hydrothermal techniques, and pave the great avenue for next-generation solution-processed photovoltaics.

Charge-Carrier Dynamics of Evaporated Bismuth-Based Chalcogenide Thin Films Probed with Time-Resolved Microwave Conductivity.

Chalcogenide-based semiconductors are emerging as a set of highly promising candidates for optoelectronic devices, owing to their low toxicity, cost-effectiveness, exceptional stability, and tunable optoelectronic properties. Nonetheless, the limited understanding of charge recombination mechanisms and trap states of these materials is impeding their further development. To fill this gap, we conducted a comprehensive study of bismuth-based chalcogenide thin films and systematically investigated the influence of post-treatments via time-resolved microwave conductivity and temperature-dependent photoluminescence. The key finding in this work is that post-treatment with Bi could effectively enhance the crystallinity and charge-carrier mobility. However, the carrier density also increased significantly after the Bi treatment. On the contrary, post-treatment of evaporated Bi2S3 thin films with sulfur could effectively increase the carrier lifetime and mobility by passivating the trap states on the grain boundaries, which is also consistent with the enhanced radiative recombination efficiency.

Optoelectronic Modulation of Silver Antimony Sulfide Thin Films for Photodetection.

Silver antimony sulfide, as a ternary chalcogenide, has attracted great attention in the field of optoelectronics in recent years. In particular, it has appealing properties, such as excellent stability, solution processability, and versatile composition tunability. Benefiting from the recent development of processing techniques, AgSbS2 has emerged as a promising candidate for next-generation, thin-film photovoltaics. On the contrary, AgSbS2-based photodetectors have been barely reported. In this work, we systematically investigated the composition engineering of silver antimony sulfide compounds with a precursor route. Their optoelectronic properties were fully characterized, and the composition was optimized for photodetection. High-performance phototransistors were first reported based on field-effect thin film transistors with interfacial modification. The obtained AgSbS2 phototransistors exhibited relatively high photosensitivity, low dark current and noise, superior device stability, and excellent detectivity covering the whole range from ultraviolet to near-infrared, highlighting the great potential for next-generation photodetection.