Electronic and optical properties of perovskite compounds MA FA PbI X (X = Cl, Br) explored for photovoltaic applications.

As outstanding light harvesters, solution-processable organic-inorganic hybrid perovskites (OIHPs) have been drawing considerable attention thanks to their higher power conversion efficiency (PCE) and cost-effective synthesis relative to other photovoltaic materials. Nevertheless, their further development is severely hindered by the drawbacks of poor stability and rapid degradation in particular. First-principles calculations based on density functional theory (DFT) are hence performed towards the perovskite compounds MA FA PbI X (X = Cl, Br), with the aim of exploring more efficient and stable OIHPs.

Efficient charge separation and visible-light response in bilayer HfS-based van der Waals heterostructures.

Two-dimensional (2D) hafnium disulfide (HfS) has been synthesized and is expected to be a promising candidate for photovoltaic applications, and at the same time the hexagonal BN sheet (h-BN) and graphene-like CN sheet (g-CN) have also been fabricated and are expected to be applied in photocatalysis. In this work, we employ hybrid density functional theory to investigate HfS-based van der Waals (vdW) heterojunctions for highly efficient photovoltaic and photocatalytic applications. HfS/h-BN and HfS/g-CN heterostructures with direct bandgaps and efficient charge separation are both typical type-II semiconductors and have potential as photovoltaic structures for solar power.