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Two-Dimensional Violet Phosphorus P 11 : A Large Band Gap Phosphorus Allotrope
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Revisiting Sub-Band Gap Emission Mechanism in 2D Halide Perovskites: The Role of Defect States
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Size-Dependent Optical Band Gaps in Metal–Organic Framework Nanoparticles
Decades of research into size-dependent semiconductor optical gaps have focused on quantum confinement as the dominant mechanism. Emerging reports indicate that lattice strain─intentional or incidental─can impart optical shifts similar or greater in magnitude. Here, we report evidence of optical absorption and photoluminescence spectra of M(1,2,3-triazolate)2 (M = Mg, Cr, Mn, Fe, Co, Cu, Zn, or Cd) nanoparticles that blueshift from bulk values with decreasing particle sizes in a manner that defies explanation by conventional quantum confinement. Here, the phenomenon persists for particle sizes as large as 200 nm, whereas quantum confinement generally ceases beyond 20–30 nm diameters and follows a weaker dependence on the particle radius. Computational simulations and crystallographic analysis suggest that this behavior arises from size-dependent changes to metal–linker bonding that manifest in strain values comparable to literature reports of strain-induced optical shifts in other classes of materials. This behavior appears beyond this family of materials in other notable examples of metal–organic frameworks (MOFs), including the well-studied Cu3(trimesate)2 (CuBTC), where smaller sizes correlate with blueshifted optical gaps. Taken together, these results represent one of the few examples of size-dependent strain in crystalline materials and reinforce the emerging view that MOFs become softer materials when isolated as nanoparticles.
Helical Peptides Design for Molecular Dipoles Functionalization of Wide Band Gap Oxides
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Band gap crossover and insulator–metal transition in the compressed layered CrPS4
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Photoinduced cationic polycondensation in solid state towards ultralow band gap conjugated polymers
A photoinduced cationic polycondensation towards the synthesis of homopolymer PTT.
23.2% efficient low band gap perovskite solar cells with cyanogen management
The role of thiocyanates in minimising organohalide diffusion into PEDOT:PSS whilst accelerating device degradation is identified and a route towards improving both device efficiency and stability is demonstrated.
Electronic band gaps from quantum Monte Carlo methods
We develop a method for calculating the fundamental electronic gap of semiconductors and insulators using grand canonical quantum Monte Carlo simulations. Further, we discuss the origin of the bias introduced by supercell calculations of finite size and show how to correct the leading and subleading finite size errors either based on observables accessible in the finite-sized simulations or from density-functional theory calculations. Our procedure is applied to carbon, silicon, and molecular hydrogen crystals, and compared to experiment for carbon and silicon.
Effect of strain on the band gap of monolayer MoS 2
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Reconciling ionization energies and band gaps of warm dense matter derived with ab initio simulations and average atom models
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Computational Identification of Ternary Wide-Band-Gap Oxides for High-Power Electronics
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