Influence of dielectric confinement on excitonic nonlinearity in inorganic-organic layered semiconductors

Abstract

We have investigated photoinduced spectral changes of excitons in inorganic-organic layered semiconductors, ͑C 6 H 5 C 2 H 4 NH 3 ͒ 2 PbI 4 ͑PhE-PbI 4 ͒ and ͑C 6 H 13 NH 3 ͒ 2 PbI 4 ͑C6-PbI 4 ͒, by means of the subpicosecond pump-probe spectroscopy. The two semiconductors consist of the same inorganic layers and different organic layers. In the two substances, the blueshift and the bleaching of the exciton are observed. It is found that both of the blueshift and the bleaching are considerably stronger in C6-PbI 4 than in PhE-PbI 4 . The weight of the blueshift relative to the bleaching is larger in PhE-PbI 4 than in C6-PbI 4 . These differences are qualitatively explained in terms of the stronger dielectric confinement in C6-PbI 4 than in PhE-PbI 4 due to the lower dielectric constant of the organic layers in C6-PbI 4 than in PhE-PbI 4 . Delay time dependences of the blueshift and the bleaching and their polarization dependences are understood as being due to the exciton relaxation in the angular momentum space with rates of 2.7 and 4.1 ps −1 for PhE-PbI 4 and C6-PbI 4 , respectively.

Effects of organic moieties on the photoluminescence spectra of perovskite-type tin bromide based compounds

“…Only a few of them are based on tin-halide compounds (see for example [1,3,5,[13][14][15]21]). The reported compounds were characterized as three-dimensional (3D) semiconductors of the type (SC)MX 3 , twodimensional (2D) or monolayer (n=1) of the type (BC) 2 MX 4 semiconductors and quasi-twodimensional (q-2D) bilayer or multilayer (n≥2) semiconductors.…”

Excitons in ultrathin organic-inorganic perovskite crystals

“…The measured dielectric constant of the bulk material is roughly ∼3. 23,30,50 In NSs, however, the dielectric surroundings are strongly affected by the presence of the substrate on the one side of the layer and vacuum on the other, as reflected in the strong decrease of the asymptotic value to approach the average of the dielectric constants of vacuum/air and fused silica (Fig.4(f)− dashed line). This effect of the dielectric screening is more pronounced for the higher excited states and is the main reason for the overall increase of the binding energy.…”

Well‐width dependence of excitonic properties in organic‐inorganic hybrid quantum well materials

“…In these materials the band gap energy difference between organic barrier layers and inorganic well layers is about 2 eV, and well width is in the order of 10 angstroms [11][12][13][14]. Therefore these materials exhibit strong quantum confinement effect (QCE).…”