A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Low band gap polymers for organic photovoltaics

Polythiophenes are one of the most important classes of conjugated polymers, with a wide range of applications, such as conducting films, electrochromics, and field-effect transistors, which have been the subject of a number of older and more recent reviews. Much less attention has been paid to the light-emitting properties of this class of materials, although their unique properties present a number of opportunities unavailable from more popular polymeric light emitters such as polyfluorene or poly(p-phenylene vinylene). This article reviews achievements to date in applications of thiophene-based polymers and oligomers as electroluminescent materials. We demonstrate the basic principles of controlling the optical properties of polythiophenes through structural modifications and review the most important light-emitting materials created from thiophene derivatives. Special attention is paid to consequences of structural variations on the performance of light-emitting diodes fabricated with these materials.

Light-Emitting Polythiophenes†

Related Systems: New Insights into Biosensing, Bioimaging, Genomics, Diagnostics, and Therapy Jun Yao,† Mei Yang,† and Yixiang Duan*,†,‡ †Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China ‡Research Center of Analytical Instrumentation, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610064, China

Chemistry, Biology, and Medicine of Fluorescent Nanomaterials and Related Systems: New Insights into Biosensing, Bioimaging, Genomics, Diagnostics, and Therapy

This Focus Review describes the emerging class of near-infrared (NIR) organic compounds containing the conjugated polyene, polymethine, and donor-acceptor chromophores and exploration of their NIR-absorbing, NIR-fluorescence, and NIR-photosensitizing properties for potential applications in heat absorbers, solar cells, and NIR light-emitting diodes Examples of NIR organic compounds are reviewed with emphasis on the molecular design, NIR absorption, and fluorescence and particular emerging applications The donor-acceptor type of NIR chromophores are particularly introduced owing to some unique features, including the designer-made energy gaps, facile synthesis, good processability, and controllable morphology and properties in the solid state Future directions in research and development of NIR organic materials and applications are then offered from a personal perspective

Near‐Infrared Organic Compounds and Emerging Applications

GaBiAs layers have been grown by molecular beam epitaxy at low (270–330°C) temperatures and were characterized by several experimental techniques. It was shown that the spectral photosensitivity cutoff wavelength reaches ∼1.4μm when the growth temperature is as low as 280°C. Optical pump–terahertz probe measurements made on these layers have evidenced that the electron trapping time decreases with decreasing growth temperature from 20 to about 1ps. GaBiAs layers were used for manufacturing photoconductive terahertz emitters and detectors, which, when excited with Ti:sapphire laser pulses, have demonstrated a signal bandwidth of 3THz.

GaBiAs: A material for optoelectronic terahertz devices

We report significant differences in the temperature dependent and time-resolved photoluminescence(PL) from low and high surface density InGaAs/GaAs quantum dots (QDs).

/pdf/inhibited-carrier-transfer-in-ensembles-of-isolated-quantum-5fk7n1w9mk.pdf

Inhibited carrier transfer in ensembles of isolated quantum dots

Photoexcited carrier dynamics was studied in n and p modulation-doped self-assembled InAs GaAs quantum dots by means of time-resolved photoluminescence with excitation and detection energies varied through barrier, wetting layer, and quantum dot states. Carrier transfer to the ground state of the dots was found to occur within 5 to 6 and 12 ps for the doped and undoped samples, respectively. The experiments suggest that in all samples the carrier capture into the highest quantum dot levels proceeds by phonon emission. The significant difference in the transfer times is attributed to different relaxation mechanisms for the subsequent process of intradot carrier relaxation. For the doped samples, the presence of built-in carriers in the dots leads to efficient electron-hole scattering, while in the undoped structure scattering by phonons is identified as the main relaxation channel. Additionally, experimental results show decreased carrier lifetimes in the doped structures, which is attributed to nonradiative recombination at doping-induced recombination centers in the vicinity of the quantum dot layers.

Carrier dynamics in modulation-doped InAs/GaAs quantum dots

We report photo- and electroluminescence from an alternating conjugated polymer consisting of fluorene units and low-band gap donor-acceptor-donor (D–A–D) units. The D–A–D segment includes two elec ...

1 micron wavelength photo- and electroluminescence from a conjugated polymer

A coherent absorption dip in pump-probe experiment performed on a ten layer optically thin InGaAs/GaAs quantum dot (QD) structure has been observed. Measurements performed for different wavelengths ...

Saulius Marcinkevicius

Papers

GaBiAs: A material for optoelectronic terahertz devices

Inhibited carrier transfer in ensembles of isolated quantum dots

Carrier dynamics in modulation-doped InAs/GaAs quantum dots

1 micron wavelength photo- and electroluminescence from a conjugated polymer

Transient electromagnetically induced transparency in self-assembled quantum dots