Inhibited Inelastic Scattering of Incoherent Excitons for Near-Band Edge Excitations.

A multiple pump-terahertz probe experiment enables the clear distinction between elastic and inelastic scattering of excitons with a free electron-hole plasma in (Ga,In)As multiquantum wells. Low plasma energies dictate the prevalence of elastic scattering by inhibiting inelastic processes due to the absence of final states for quasiparticles. Yet, an increased plasma energy results in a progressive destruction of excitons.

Atomically Thin Sheets of Lead-Free 1D Hybrid Perovskites Feature Tunable White-Light Emission from Self-Trapped Excitons.

Low-dimensional organic-inorganic perovskites synergize the virtues of two unique classes of materials featuring intriguing possibilities for next-generation optoelectronics: they offer tailorable building blocks for atomically thin, layered materials while providing the enhanced light-harvesting and emitting capabilities of hybrid perovskites. This work goes beyond the paradigm that atomically thin materials require in-plane covalent bonding and reports single layers of the 1D organic-inorganic perovskite [C H N] [BiCl ]Cl. Its unique 1D-2D structure enables single layers and the formation of self-trapped excitons, which show white-light emission.

Controlling the White-Light Generation of [(RSn) E ]: Effects of Substituent and Chalcogenide Variation.

Adamantane-type organotin chalcogenide clusters of the general composition [(RT) S ] (R=aromatic substituent, T=Si, Ge, Sn) have extreme non-linear optical properties that lead to highly directional white-light generation (WLG) upon irradiation with an IR laser diode. However, the mechanism is not yet understood. Now, a series of compounds [(RSn) E ] (R=phenyl, cyclopentadienyl, cyclohexyl, benzyl, CH CH (C H )CO Et; E=S, Se), were prepared, characterized, and investigated for their nonlinear optical properties.