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Chen H.-C.,National Chiao Tung University | Lin C.-C.,National Chiao Tung University | Han H.-V.,National Chiao Tung University | Chen K.-J.,National Chiao Tung University | And 6 more authors.
Asia Communications and Photonics Conference, ACP

This study demonstrates the high performance of GaAs solar cells with double-layer quantum dots carried by flexible PDMS film. Several parameters were enhanced. Different concentrations of QDs were also applied to test the optimal combination. © 2012 OSA. Source

Lin C.-C.,National Chiao Tung University | Chen H.-C.,National Chiao Tung University | Tsai Y.L.,National Chiao Tung University | Han H.-V.,National Chiao Tung University | And 4 more authors.
Optics Express

We demonstrate a hybrid design of traditional GaAs-based solar cell combined with colloidal CdS quantum dots. With anti-reflective feature at long wavelength and down-conversion at UV regime, the CdS quantum dot effectively enhance the overall power conversion efficiency by as high as 18.9% compared to traditional GaAs-based device. A more detailed study showed an increase of surface photoconductivity due to UV presence, and the fill factor of the solar cell can be improved accordingly. © 2012 Optical Society of America. Source

Kuo Y.-K.,National Changhua University of Education | Lin B.-C.,National Changhua University of Education | Chang J.-Y.,National Changhua University of Education | Chang Y.-A.,Millennium Communication Co.
IEEE Photonics Technology Letters

A compositional grading layer between the p-In0.5Ga 0.5P emitter layer and p-In0.5Al0.5P window layer in the p +-n In0.5Ga0.5P solar cell is investigated numerically. With the insertion of the grading layer, the short-circuit current density and conversion efficiency are improved due to the enhancement of carrier-collection efficiency, which can be ascribed to the reduction of potential barrier height in the valance band and the existence of internal quasi-electric field in the conduction band. An optimized value of conversion efficiency can be obtained by appropriately adjusting the thickness of the grading layer. © 2011 IEEE. Source

Wang H.W.,National Chiao Tung University | Chen H.C.,National Chiao Tung University | Chang Y.A.,Millennium Communication Co. | Lin C.C.,National Chiao Tung University | And 5 more authors.
IEEE Photonics Technology Letters

In this study, p-i-n double-heterojunction GaN/In0.11Ga 0.89N solar cells grown by metal-organic chemical vapor deposition on pattern sapphire substrate are presented. The solar cell with standard process has a conversion efficiency of 3.1%, which corresponds to a fill factor of 58%, short circuit current density of 2.86 mA/cm2 , and open circuit voltage of 1.87 V under AM1.5G illumination. To further improve the conversion efficiency of the GaN/In0.11Ga0.89N solar cells, two-dimensional polystyrene nanospheres were deposited and self-organized as mask in the anisotropic inductively coupled plasma reactive ion etching process to form a biomimetic surface roughing texture. The surface morphology of the solar cell shows a periodically hexagonal bead pattern and the beads are formed in a diameter of 160 nm with a period of 250 nm. An increase of 15% in short circuit current density is found, thus improving the conversion efficiency to 3.87%. If we optimize the structure for 180 nm of the height and 375 nm of the period, a 10% gain can be expected when compared to the current structure. © 2011 IEEE. Source

Millennium Communication Co. | Date: 2012-05-23

An optical lens for modulating light generated by a surface-emitting laser chip is disclosed. The optical lens includes a main body with a recess. A bottom surface of the recess is configured with a light-entering curved face, and an outer surface of the main body opposite to the bottom surface is configured with a light-existing curved face. Here, the recess is for accommodating the surface-emitting laser chip, and the surface-emitting laser chip is arranged a distance from the light-entering curved face. A light-emitting module adopting the aforementioned optical lens is also provided. The aforementioned optical lens would cause the incident light to first diverge and then converge at a predetermined angle, so that the output illuminating light is more uniform and the projecting distance is extended.

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