B-Site Co-Doping Coupled with Additive Passivation Pushes the Efficiency of Pb-Sn Mixed Inorganic Perovskite Solar Cells to Over 17

Pb-Sn mixed inorganic perovskite solar cells (PSCs) have garnered increasing interest as a viable solution to mitigate the thermal instability and lead toxicity of hybrid lead-based PSCs. However, the relatively poor structural stability and low device efficiency hinder its further development. Herein, high-performance manganese (Mn)-doped Pb-Sn-Mn-based inorganic perovskite solar cells (PSCs) are successfully developed by introducing Benzhydroxamic Acid (BHA) as multifunctional additive. The incorporation of smaller divalent Mn cations contributes to a contraction of the perovskite crystal, leading to an improvement in structural stability. The BHA additive containing a reductive hydroxamic acid group (O═C-NHOH) not only mitigates the notorious oxidation of Sn2+ but also interacts with metal ions at the B-site and passivates related defects. This results in films with high crystallinity and low defect density. Moreover, the BHA molecules tend to introduce a near-vertical dipole moment that parallels the built-in electric field, thus facilitating charge carrier extraction. Consequently, the resulting device delivers a champion PCE as high as 17.12%, which represents the highest reported efficiency for Pb-Sn-based inorganic PSCs thus far. Furthermore, the BHA molecule provides an in situ encapsulation of the perovskite grain boundary, resulting in significant enhancement of device air stability.

Nitrogen and Sulfur Co-Doped Graphene-Like Carbon from Industrial Dye Wastewater for Use as a High-Performance Supercapacitor Electrode

Nitrogen and sulfur co-doped graphene-like carbon (N,S-GLC) is successfully prepared in a one-step hydrothermal reaction of glucose with industrial dye wastewater followed by chemical activation. The nitrogen and sulfur are sourced entirely from the industrial wastewater. The process not only provides an alternative way of treating industry wastewater, but also offers a green route for recovering energy from the waste in the form of chemicals. The resultant N,S-GLC shows a good degree of graphitization, a high specific surface area (1734 m2 g-1), and moderate heteroatom doping (N: 2.1 at%, S: 0.7 at%). The N,S-GLC electrode displays high specific capacitance of 275 F g-1 at a current density of 0.5 A g-1 with a retention of 65.4% at 20 A g-1 in 6 m KOH. Moreover, the assembled symmetrical supercapacitor cell shows a capacitance of 38 F g-1 at a current density of 0.5 A g-1, which is equivalent to an energy density of 6.4 Wh kg-1 at a power density of 275.0 W kg-1. This approach provides an alternative and sustainable way of fabricating heteroatom-doped graphene-like carbon materials for use in high-performance supercapacitors.