Temperature Dependence Of Photoluminescence Lifetime Research Articles

Te4+-doped Cs2InCl5·H2O single crystals for remote optical thermometry

Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties. Particularly, metal halides with the ns2 electronic configuration are of great interest owing to the high-temperature sensitivity of their photoluminescence, which could be applied to remote optical thermometry (ROT). Herein, all-inorganic and lead-free halide perovskite Te4+-doped Cs2InCl5·H2O single crystals (SCs) were prepared through the hydrothermal method and showed a strong temperature dependence of photoluminescence lifetime. Upon Te4+ doping, the nonemissive Cs2InCl5·H2O SC exhibits a bright orange emission at 660 nm with a wide full width at half maximum of 180 nm. The strong phonon-exciton coupling promotes the formation of self-trapped excitons in the soft lattice of the zero-dimensional Te4+-doped Cs2InCl5·H2O SC. The Te4+ ions with the 5s2 electronic configuration endow the Te4+-doped Cs2InCl5·H2O SC with a strong temperature-dependent photoluminescence lifetime. This SC reaches a maximum specific sensitivity of 0.062K−1 at 320 K, thereby showing the potential advantages of indium-based metal halide perovskites in ROT applications.

Temperature dependence of photoluminescence lifetime of atomically-thin WSe2 layer

At cryogenic temperatures, the photoluminescence (PL) spectrum of monolayer WSe2 features a number of lines related to the recombination of so-called localized excitons (LEs). The intensity of these lines strongly decreases with increasing temperature. In order to understand the mechanism behind this phenomenon we carried out a time-resolved experiment, which revealed a similar trend in the PL decay time. Our results identify the opening of additional non-radiative relaxation channels as a primary cause of the observed temperature quenching of the LEs’ PL.

Mechanistic understanding of the charge carrier trapping in CsPbCl3 perovskite nanocrystals

The optical properties of CsPbCl3 perovskite nanocrystals (NCs) with varied sizes were studied in the temperature range from 80 to 320 K by steady-state and time-resolved photoluminescence (PL) spectroscopy. The CsPbCl3 NCs were synthesized with a hot-injection approach at reaction temperature of 140–180 °C. The PL emissions in NC films originate from localized excitons. It is found that NC films shows a significant decrease in PL intensity with increasing temperature while they exhibit a clear increase in PL lifetime from 80 K to around 250 K and then a reduction at high temperature. The abnormal temperature dependence of PL lifetimes in NC films is related to thermal activation of trapped carriers in the NCs. The change of average lifetimes with emission energy indicates the thermal degradation result from the loss of ligands on the surface of NC films. Moreover, the PL intensities, peak energies, and bandwidths of the NC films as a function of temperature are discussed detail.

Temperature-Dependent Exciton Recombination Dynamics of CdTe Nanocrystals

Exciton recombination dynamics of zinc-blende CdTe nanocrystals (NCs) have been investigated by using an ionic liquid as a cryogenic matrix. Size and temperature dependence of photoluminescence lifetimes of CdTe NCs were studied by time-resolved spectroscopy. The photoluminescence properties in a low-temperature range were characterized by a simple three-level model where populations of two emitting states in CdTe NCs are determined by Boltzmann distribution. Observation at low temperature suggests that the relaxation pathway is dependent on the population between two kinds of excited states of the CdTe NC generated by an electron−hole exchange interaction in the tightly confined particle-in-a-box system.

Temperature Dependence of Photoluminescence Lifetime and Quantum Efficiency in Neat fac-Ir(ppy)3 Thin Films

Temperature dependences of lifetime and intensity of photoluminescence have been investigated in neat fac-Ir(ppy)3 thin films, which have a nonradiative decay channel due to aggregate quenching. Both temperature dependences can be well understood by a model which consists of three substates of the triplet metal-to-ligand-charge-transfer (3MLCT) state and a nonemissive state. Good agreement between the experimental results and the calculations based on the model suggests that nonradiative decay occurs through a higher lying excited state in fac-Ir(ppy)3 molecules, and that the nonemissive excited state has a decay rate of 3.1×109 s-1 and is located at 0.12 eV above the lowest substate of the 3MLCT state.

Temperature dependence of emission lifetime in electron trapping materials

In this paper, temperature dependences of emission lifetimes in electron trapping materials are studied, such as the temperature dependences of infrared stimulated luminescence lifetime and photoluminescence lifetime in SrS (Eu, Sm) electron trapping materials. For comparison, the temperature dependence of photoluminescence lifetime in SrS (Eu) is also studied. The experimental results are explained by the optical storage mechanisms of electron trapping materials recently proposed by us.

Temperature dependence of photoluminescence lifetimes in ordered GaInP2

The temperature dependence of carrier lifetimes in ordered (o) GaInP2 epilayers was investigated with and without cladding layers of disordered (d) GaInP2. The extremely long lifetime of the emission that moves with laser excitation density and the shorter lifetime of the nonmoving emission persist up to T=50 and 300 K, respectively. Both decays involve localized holes. By removal of the d top layer of the double heterostructure, an enhanced hole diffusion to the surface occurs, which results in a slightly faster, nonexponential decay. It is argued that, within the nominally o layer, a type II recombination occurs and that o and d GaInP2 exhibit a type II band lineup. The appropriate band curvatures in the d top layer cause hole localization at the d side of the o–d interfaces. The minority carrier lifetime shows two-dimensional behavior between T=70 and 170 K, and decrease above 170 K.