Equipment

Nano/picosecond transient absorption spectrometer

Detection of transient absorption spectra and their time profile of excited state, reaction intermediate, and charge carrier produced by pulse laser irradiation.

Nano/picosecond luminescence lifetime spectrometer

Detection of luminescence spectra and lifetime by pulse laser irradiation.

Applications

• Liquids, particles, single crystals, thin films, devices
• Dynamics of charge carrier, excited state, and reaction intermediate
• Lifetime of fluorescence, phosphorescence and delayed fluorescence

Principle and Features

• Formation of the transient state of samples by irradiation with femto- or pico-second pulsed laser light
• Measurement of the time profile of absorbance or luminescence intensity of samples in the transient state Non-destructive and high sensitive (ppm) detection of atomic and nanoscale voids Measurement with different characteristic implantation depth by varying the positron beam energy
• Detection of reaction intermediate, and evaluation of rate of charge carrier generation, transport, recombination and dissociation processes, and evaluation of generation and decay rate of excited states and species

Examples

• Deterioration test of Si solar cell
• The amount of conduction carriers produced in Si solar cells was determined from the time dependence of light absorbance by the carriers. A decrease of the absorbance at the surface region of the cells after degradation was confirmed by using surface sensitive excitation light at shorter wavelengths. This result indicates that the degradation of Si solar cells occurs at their surface.

• Revealing the excited-state dynamics of organic electroluminescent materials
• Highly efficient thermally activated delayed fluorescence (TADF) materials form specific species in the excited state. Based on this information, a new mechanism of TADF is proposed

Transient absorption spectral map of highly efficient TADF molecule (upper) and new TADF mechanism (lower)

• Photoluminescence dynamics of room-temperature phosphorescent materials
• The photophysical properties of room-temperature phosphorescent (RTP) materials were investigated using a fluorescence lifetime spectrometer. For three kinds of benzil derivatives, mono benzil derivative 1 was revealed to exhibit the most efficient RTP.

Room-temperature phosphorescent materials (upper) and their luminescence time profiles (lower)

Other examples

• Nanoparticles, perovskite materials, photocatalysts, metal-oxide semiconductors, optical light fiber materials, nanocarbon materials, photosensitive materials, circular polarization materials, organometallic materials, cells, proteins, fluorescence probe materials