1D/2D TiO_(2)/ZnIn_(2)S_(4) S-scheme heterojunction photocatalyst for efficient hydrogen evolution

TiO_(2)is a promising photocatalyst with limited use in practical applications owing to its wide bandgap,narrow light response range,and rapid recombination of photoexcited carriers.To address these limitations,a novel 1D/2D TiO_(2)/ZnIn_(2)S_(4)heterostructure was designed according to the principles of the S-scheme heterojunction.The TiO_(2)/ZnIn_(2)S_(4)(TZISx)hybrids prepared via a hydrothermal method afforded significant improvement in photocatalytic hydrogen evolution(PHE)in comparison to pristine TiO_(2)and ZnIn_(2)S_(4).In particular,the optimal TZIS2 sample(mass ratio of ZnIn_(2)S_(4)to TiO_(2)was 0.4)exhibited the highest PHE activity(6.03 mmol/h/g),which was approximately 3.7 and 2.0 times higher than those of pristine TiO_(2)and ZnIn_(2)S_(4),respectively.This improvement in the PHE of the TZIS2 sample could be attributed to the formation of an intimate heterojunction interface,high-efficiency separation of charge carriers,abundant reactive sites,and enhanced light absorption capacity.Notably,theoretical and experimental results demonstrated that the S-scheme mechanism of interfacial electron transfer in the TZISx composites facilitated the transfer and separation of photoexcited charge carriers,resulting in more isolated photoexcited electrons for the PHE reaction.

Improving the stability of metal halide perovskite solar cells from material to structure

Metal halide perovskites(MHPs) are promising photovoltaic(PV) materials owing to their advantages such as high carrier mobility, excellent absorption coefficient, bandgap tenability, long diffusion length,and low material cost. These qualities have increased the efficiency of MHP solar cells to 23.3%. However,MHPs are hindered by a lack of stability. In addition, the applications of MHP solar cells are restricted by the instability of perovskite materials and devices. In this article, the most urgent stability problems faced by perovskite solar cells are identified, and recent progresses in MHPs are enumerated. The factors affecting the stability of perovskite materials and devices are also discussed. We analyzed the thermal and humid stability of perovskite materials in terms of transporting materials and their interface. In view of these recent advances, future works should focus on the large-scale application of MHP solar cells.

Anti-solvent assisted treatment for improved morphology and efficiency of lead acetate derived perovskite solar cells

An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and device architectures on the morphologies of perovskite films were systematically investigated. Our results show that the planar perovskite layer fabricated by one-step solution method achieved fully covered and pinhole-free films. Further anti-solvent treatment using chlorobenzene (CB) promoted a perovskite film with highly smooth surfaces and enlarged grain sizes. Device fabricated from CB treated perovskite film achieved a best PCE of 15.80%, in comparison with 14.02%for the untreated device. These results evidently suggest a feasible route towards controlling the crystallization and morphology of planar heterojunction (PHJ) PSCs for improved efficiency.