Green Stimulated Emission Boosted by Nonradiative Resonant Energy Transfer from Blue Quantum Dots

Thanks to their tunability and versatility, the colloidal quantum dots (CQDs) made of II-VI semiconductor compound offer the potential to bridge the "green gap" in conventional semiconductors. However, when the CQDs are pumped to much higher initial excitonic states compared to their bandgap, multiexciton interaction is enhanced, leading to a much higher stimulated emission threshold. Here, to circumvent this drawback, for the first time, we show a fully colloidal gain in green enabled by a partially indirect pumping approach assisted by Förster resonance energy transfer process. By introducing the blue CQDs as exciton donors, the lasing threshold of the green CQDs, is reduced dramatically. The blue CQDs thus serve as an energy-transferring buffer medium to reduce excitation energy from pumping photons in a controlled way by injecting photoinduced excitons into green CQDs. Our newly developed colloidal pumping scheme could enable efficient CQD lasers of full visible colors by a single pump source and cascaded exciton transfer. This would potentially pave the way for an efficient multicolor laser for lighting and display applications. © 2016 American Chemical Society

High brightness formamidinium lead bromide perovskite nanocrystal light emitting devices

Formamidinium lead halide (FAPbX3) has attracted greater attention and is more prominent recently in photovoltaic devices due to its broad absorption and higher thermal stability in comparison to more popular methylammonium lead halide MAPbX3. Herein, a simple and highly reproducible room temperature synthesis of device grade high quality formamidinium lead bromide CH(NH2)2 PbBr3 (FAPbBr3) colloidal nanocrystals (NC) having high photoluminescence quantum efficiency (PLQE) of 55-65% is reported. In addition, we demonstrate high brightness perovskite light emitting device (Pe-LED) with these FAPbBr3 perovskite NC thin film using 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) commonly known as TPBi and 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) as electron transport layers (ETL). The Pe-LED device with B3PYMPM as ETL has bright electroluminescence of up to 2714 cd/m2, while the Pe-LED device with TPBi as ETL has higher peak luminous efficiency of 6.4 cd/A and peak luminous power efficiency of 5.7 lm/W. To our knowledge this is the first report on high brightness light emitting device based on CH(NH2)2 PbBr3 widely known as FAPbBr3 nanocrystals in literature. © The Author(s) 2016

Proton-beam writing of poly-methylmethacrylate buried channel waveguides

10.1109/JLT.2006.881474Journal of Lightwave Technology24103803-3809JLTE

Sub 100 nm proton beam micromachining: theoretical calculations on resolution limits

10.1016/S0168-583X(99)00862-9Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms161366-370NIMB

A LabVIEW™-based scanning and control system for proton beam micromachining

10.1016/S0168-583X(01)00554-7Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms1811-449-53NIMB

Fabrication of micro-optical components in polymer using proton beam micro-machining and modification

10.1016/S0168-583X(03)01021-8Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms210250-255NIMB

Tunable giant multi-photon absorption using seeded CdSe/CdS nanorod heterostructures

2012 Conference on Lasers and Electro-Optics, CLEO 2012

Fabrication of micro-optical components in polymer using proton beam writing

10.1117/12.524300Proceedings of SPIE - The International Society for Optical Engineering5347255-263PSIS

The use of proton microbeams for the production of microcomponents

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms161-16383-89NIMB

Direct measurement of proton-beam-written polymer optical waveguide sidewall morphorlogy using an atomic force microscope

10.1063/1.1784035Applied Physics Letters8581398-1400APPL