Of particular interest in the display industry is mastering the QDLED technology for developing low-cost, long lifetime, efficient, bright, color-saturated, and large-area color displays compatible with flexible substrates through solution-based processing. High expectations regarding this type of display result from the superior performance of QDLEDs in comparison to conventional display devices, such as cathode-ray tubes (CRTs), liquid crystal displays (LCDs), and organic light-emitting-diodes (OLEDs). Ocean NanoTech is currently developing high quality QDs for this application through alterations and improvements of the inorganic and organic coatings to capture a portion of this multi-billion dollar opportunity. With support from the NSF, NIH and DOD, as well as our academic partners, Ocean NanoTech has demonstrated the excellent electroluminescent efficiency of our high quality QD powders at electronic grade and delivered red, green, and blue QDLEDs to the market, which paves the way for revolutionary advances in the display industry. More detailed information about Ocean NanoTech’s QDLEDs and their device performance can be found in our publication at Nature Photonics, Nano Letters, APL and ACSnano.
B. Solid-state lighting
Solid-state lighting (SSL) uses light emitting diodes (LEDs), organic light emitting diodes (OLEDs), or polymer light emitting diodes (PLEDs) as sources of illumination rather than electrical filaments, plasma (used in arc lamps such as fluorescent lamps), or gas. Solid state refers to emission of light from a solid block of semiconductor rather than from a vacuum of gas tube as in the case of traditional incandescent light bulbs and fluorescent lamps. Unlike incandescent light, SSL creates visible light with reduced heat generation or parasitic energy dissipation, similar to that of fluorescent lighting. Its solid-state nature provides for greater resistance to shock, vibration, and wear, which increases its lifespan significantly. SSL is often used in modern vehicle lights, train marker lights, remote controls and traffic lights. Among the many potential applications of white LEDs, SSL has recently commanded much attention as a cost-competitive energy efficient alternative to conventional electrical lighting. QDs as SSL emitters offer high color tenability, high emission efficiency and the possibility of mass production.
C. Solar cells:
Colloidal QDs as photovoltaic materials have drawn more and more attention in solar cell research. The following unique properties of QDs make it possible to produce inexpensive and high efficient solar cells on flexible substrate:
• Solution-based synthesis and process offers flexibility
in the selection of substrate and leads to lower manufacturing cost of solar cells;
• Size dependent melting point makes it possible to
fabricate solar cells at low temperature with high crystallization to reduce the energy cost;
• Tunable band edge offers possibility to harvest light
over a wide range of wavelengths from visible to infrared;
• Hot carrier injection from higher excited state can
minimize energy loss during thermalization of excited state for efficient light-electricity conversion;
• Multiple carrier generation leads to high efficient solar
• Soluble in both organic solvents and water makes it
possible to combine QDs with conducting polymer to fabriate hybrid solar cells.
Ocean NanoTech offers CdSe core QDs with different surface ligands such as octadecylamine, trioctylphousphie oxide and mercapopropionic acid , as well as cadmium-free QDs for solar cell research.