REMINDER: CrystEngComm - Invitation to submit an article Band gap modulation of organic-inorganic Sb(Ⅲ) halide by molecular design

Organic-inorganic hybrid materials have structural diversity and flexibility. The introduction of Sb(Ⅲ) metal ions in the inorganic part can bring about semiconductor performance. In this paper, we successfully adjusted the...

Strain-Tuned Structural, Mechanical and Electronic Properties of Two-Dimensional Transition Metal Sulfides ZrS2: A First Principles Study1

Two-dimensional semiconductor material zirconium disulfide (ZrS2) monolayer is a new promising material with good prospects for nanoscale applications. Recently, a new zirconium disulfide (ZrS2) monolayer with a space group of 59_Pmmn has been successfully predicted. Using first-principles calculations, this new monolayer ZrS2 structure is obtained with stable indirect band gaps of 0.65 eV and 1.46 eV at the DFT-PBE (HSE06) functional levels, respectively. Strain engineering studies on ZrS2 monolayer show effective band gap modulation. The bandgap shows a linear regularity from narrow to wide under applied stresses (strain ranged from − 6% to + 8%). Young's modulus of elasticity of ZrS2 rectangular cells along the tensile directions (x-axis and y-axis) is 83.63 (N/m) and 63.61 (N/m) with Poisson's ratios of 0.09 and 0.07, respectively. The results of carrier mobility show that the electron mobility along the y-axis can reach 1.32×103 cm2V− 1s− 1. Besides, the order of magnitude of the light absorption coefficient in the ultraviolet spectral region is calculated to reach 2.0×105cm−1 for ZrS2 monolayers. Moreover, by regulating the bandgap under stress, some bandgaps of the stretched energy band exceed the free energy of 1.23 eV and possess a suitable energy band edge position. The results indicates that the new two-dimensional Pmmn-ZrS2 monolayer is a potential material for photovoltaic devices and photocatalytic water decomposition.

Emergence of Distinct Electronic States in Epitaxially-Fused PbSe Quantum Dot Superlattices

Quantum coupling in arrayed nanostructures may induce novel mesoscale properties such as electronic minibands that may lead to applications including high efficiency solar cells. Colloidal PbSe quantum dots (QDs) can self-assemble into epitaxially-fused superlattices (epi-SLs), making them a promising material system to study collective phenomena. In the present study, the presence of distinct local electronic states induced by crystalline necks connecting individual PbSe QDs is documented by several techniques that leads to modulation of the band gap energy across the epi-SL. The energy band gap measured by multi-probe scanning tunneling spectroscopy (STS) shows variation from 0.7 eV at the center of the QDs to 1.1 eV at their necks. Complementary monochromated electron energy-loss spectroscopy (EELS) measurements reveal the presence of distinct electronic states from necks in the epi-SL, confirming the STS measurements and demonstrating band gap modulation in spectral mapping. It is hypothesized that these new electronic states are induced by quantum confinement of carriers in the necks between the QDs, redefining the energy landscape of the PbSe QD epi-SL.