Photoluminescence Process Overview

The temporary absorption of light and subsequent emission of light from matter.

Involves excitation, relaxation, and emission of light.

Phase where a material absorbs light, moving electrons to a higher energy level.

Phase where electrons return to their original energy level.

Phase where the material releases light as electrons return to lower energy levels.

Different discrete energy states for electrons in atoms or molecules.

Movement of electrons between different energy levels in an atom or molecule.

How excited electrons return to ground state (emitting light/not emitting light).

The shift of emitted light towards a longer wavelength (lower energy) compared to absorbed light, due to energy loss in non-radiative decay.

A type of photoluminescence where materials emit light immediately after absorbing UV radiation, stopping as soon as the excitation source is removed.

A type of photoluminescence where materials emit light after absorbing UV radiation, but the glow continues for a longer period even after the excitation source is removed.

A nondestructive technique that uses light to study the electronic structure of materials by analyzing emitted light.

PL spectroscopy gives information only on the low lying energy levels of the investigated system.

During PL spectroscopy, materials are excited using laser light with an energy higher than the material's band gap.

After excitation, electrons and holes relax towards their respective band edges and recombine, emitting light at the energy of the band gap.

A process in which excited electrons lose energy without emitting light, causing the Stokes shift (lower energy emission).

Analyzing a material's photoluminescence (PL) spectrum reveals important properties like composition, stress/strain, orientation, quality, and abundance of specific features.

The specific frequency of a PL peak indicates the material's composition, as different elements or molecules emit light at distinct frequencies.

Changes in the frequency of a PL peak indicate stress or strain within the material, affecting its energy levels and emission.

The width of a PL peak reveals the quality of the material, broader peaks indicating more disorder or defects.

The intensity of a PL peak reflects the abundance of the corresponding feature in the material.

PL spectrum measures transitions from excited state to ground state, while absorption spectrum measures transitions from ground state to excited state.

Nanomaterials exhibit unique PL properties due to their size-dependent quantum effects, leading to specific emission wavelengths based on their size.

Surface states in nanomaterials, like Si-O and Si-H bonds, can enhance photoluminescence, contributing to the overall emission intensity.

The intensity of a PL peak reflects the abundance of the corresponding feature in the material.

The specific frequencies of PL peaks reveal the material's composition, as different elements or molecules emit light at distinct frequencies.

When one broad PL peak is actually a combination of multiple peaks, de-convolution is needed to separate and identify them.

PL spectrum measures transitions from excited state to ground state, while absorption spectrum measures transitions from ground state to excited state.

The size of nanomaterials directly influences their PL properties, leading to specific emission wavelengths based on their size.

Photoluminescence spectroscopy (PL) is a non-destructive technique used to analyze the electronic structure of materials by studying emitted light.

Two ways excited electrons can return to their ground state: Radiative emits light, Non-radiative does not.

Photoluminescence spectroscopy is used to investigate the electronic structure of materials by analyzing the emitted light. It is a powerful tool for characterizing materials and their properties.

During a PL spectroscopy experiment, a laser light with an energy greater than the material's band gap is used to excite the material. Excited electrons and holes relax to their band edges and recombine, emitting light at the energy of the band gap.

PL spectroscopy provides information about the low lying energy levels of the material, its composition, stress/strain, orientation, quality, and the abundance of specific features.

The intensity and spectral content of the emitted light in PL are directly related to the electronic structure of the material, reflecting its energy levels, transitions, and other properties.