Nasser Peyghambarian

Molecular self-assembly approaches to multilayer organic light-emitting-diode structures

An attractive and challenging approach to the construction of robust, structurally precise thin film materials with large second-order optical nonlinearities or electroluminescent characteristics is the covalent self-assembly of arrays of tailored molecular building blocks. In this contribution, we discuss the implementation of self-limiting siloxane self- assembly processes to achieve the fabrication of structurally regular organic LED (OLED) devices. Areas surveyed include: (1) the use of layer-by-layer self-assembly for ITO electrode modification/passivation/hole-electron carrier balancing in vapor deposited devices, (2) the synthesis of chlorosilane- functionalized precursor molecules for hole transport (HTL), emissive layer (EML), and electron transport layer (ETL) self- assembly, (3) the physicochemical and microstructural characterization of the HTL self-assembly process employing a triarylamine precursor, (4) the fabrication and characterization of a hybrid self-assembled + vapor deposited two-layer OLED, (5) the fabrication and characterization of a fully self-assembled two-layer OLED.

Fiber-based thz sources based on monolithic single-frequency pulsed fiber lasers in the C-band

Compact, efficient, narrow linewidth, fiber based THz sources have been achieved by using the monolithic high power single-frequency pulsed fiber lasers in MOPA based on difference-frequency generation (DFG) in nonlinear optical crystals. We have observed the external cavity enhancement of DFG THz generation by using ZnGeP2 for the first time, and implemented a high spectral resolution THz spectrometer based on the developed fiber-based tunable narrow linewidth THz source.

Molecular Self-Assembly Routes to Optically Functional Thin Films: Electroluminescent Multilayer Structures

This contribution describes the use of layer-by-layer self-limiting siloxane chemisorption processes to self-assemble structurally regular multilayer organic LED (OLED) devices. Topics discussed include: (1) the synthesis of silyl-functionalized precursor molecules for hole transport layer (HTL), emissive layer (EML), and electron transport layer (ETL) self-assembly, (2) the use of layer-by-layer self-assembly for ITO electrode modification/passivation/hole-electron balancing in a vapor-deposited device, (3) the microstructure/chemical characterization of HTL self-assembly using a prototype triarylamine precursor, (4) fabrication and properties of a hybrid self-assembled + vapor deposited two-layer LED, and (5) fabrication and properties of a fully self-assembled two-layer OLED.

All-Fiber Source of High-Power Picosecond Pulses at 1.5um Using Short and Heavily Doped Phosphate-Fiber Amplifier

We report an all-fiber source of high-power picosecond pulses at 1.5µm. Rapid amplification in heavily-doped phosphate fiber produces pulses with peak power of 16.6kW while pulse distortion is minimal in either temporal or spectral domain.

Sub-Picosecond Pulse Amplification in a Short Length, Highly Doped Erbium/Ytterbium Phosphate Fiber Amplifier

We demonstrate sub-picosecond pulse amplification in a single mode, high gain, and short length (8cm) erbium-ytterbium phosphate fiber amplifier. The amplifier operates in saturation producing 100 mW of average power and 2 nJ per pulse.