Abstract: The present invention provides a fabrication method for casting graphene quantum dots on LEDs and the structure thereof. A graphene and an ethanol are mixed uniformly. After the laser ablation, centrifugal purification, and molecular filtration processes, a graphene quantum dots solution is produced. Afterwards, the graphene quantum dots solution is dripped on a light-emitting surface of an LED using a drop casting method. After the ethanol evaporates by standing still, a graphene-quantum-dot-cast layer is formed. The photocarriers in the graphene-quantum-dot-cast layer generated by the illumination of the LED can flow to the light-emitting surface of the LED and thus increasing the carrier concentration and the light-emitting quantum efficiency of the LED. Thereby, enhancing the fluorescent efficiency of the LED.

Abstract: A graphene quantum dots synthesis method includes fixing a graphene aqueous solution or a graphene oxide aqueous solution on a spin coater to spin the graphene aqueous solution or the graphene oxide aqueous solution, and irradiating a pulsed laser to focus on a graphene aqueous solution or a graphene oxide aqueous solution to generate exfoliation. After a processing period, quantum dots are generated in the graphene aqueous solution or the graphene oxide aqueous solution. Since graphene aqueous solution or graphene oxide aqueous solution does not contain organic chemistry pharmacy, the quantum dots synthesized by the method of the present invention can be produced without pollution. Furthermore, the purpose of simple process, low cost, and time-saved of synthesis can be achieved.

Abstract: A graphene quantum dots synthesis method includes fixing a graphene aqueous solution or a graphene oxide aqueous solution on a spin coater to spin the graphene aqueous solution or the graphene oxide aqueous solution, and irradiating a pulsed laser to focus on a graphene aqueous solution or a graphene oxide aqueous solution to generate exfoliation. After a processing period, quantum dots are generated in the graphene aqueous solution or the graphene oxide aqueous solution. Since graphene aqueous solution or graphene oxide aqueous solution does not contain organic chemistry pharmacy, the quantum dots synthesized by the method of the present invention can be produced without pollution. Furthermore, the purpose of simple process, low cost, and time-saved of synthesis can be achieved.

Abstract: External cavity semiconductor lasers using a saturable Bragg reflector as an external reflector are mode locked and produce output pulses of 1.9 ps from a semiconductor lasers without dispersion compensation. By coupling the output to a standard single mode fiber with a length of 35 m to compensate the linear chirp, the mode-locked pulse duration as short as 880 fs is achieved.