Research Terms
Dr. Gao received his Bachelor’s Degree in Physics from University of Science and Technology of China in 2004 and his Doctorate Degree in Materials Science from Northwestern University in 2009. Since 2010, he worked at Lawrence Berkeley National Laboratory and University of California-Berkeley as a Postdoctoral Researcher. Dr. Gao joined the Physics Faculty of FSU in 2013.
Dr. Gao’s research encompasses physics and chemistry of solid-state nanomaterials with photonic and optoelectronic functions. His current projects investigate plasmonic and electronic properties of hybrid metal-semiconductor nanostructures for improved solid-state light emitting and solar energy harvesting applications.
As LED technology advances, there is a need for cost effective materials with incredible performance. Solution-processable electronic materials have attracted great attention for the low-cost, scalable fabrication of lightweight, flexible devices. Recently, earth-abundant organometal halide perovskites that can be solution processed have emerged as a new class of semiconductors for photovoltaic devices. However, the performance of perovskite-based LEDs (PeLEDs) reported to date has not reached the level of performance typically associated with organic or quantum dot based LEDs that share similar device architecture and operating mechanisms.
FSU researchers have fabricated bright light-emitting diodes (LEDs) based on solution-processable organometal halide perovskite nanoplatelets. These ligand-capped nanoplates are stable in moisture which allows the perovskite-based LEDs to be fabricated without an inert-gas glovebox. This novel technology demonstrates a new pathway toward optoelectronic devices based on solution-processable materials. Nanoscale organic-inorganic halide perovskites are a new class of semiconductors with desirable characteristics for optoelectronic devices.
Solution-processed halide perovskites are photoactive materials that may be used to produce low-cost, high-performance optoelectronics. For example, perovskite-based solar cells having efficiencies of at least 20 %, and perovskite-based light emitting diodes (PeLEDs) having high brightness and tunable color across the entire visible range have been produced. PeLEDs typically include organic-inorganic hybrid perovskites, such as CH3NH3PbBr3, as emitters.
This technology comprises films, PeLEDs, and methods of making films that address disadvantages experienced in this field. In some embodiments of the technology, the methods include providing a precursor formulation that includes an all-inorganic perovskite, a polymer, and a liquid, wherein the weight ratio of the polymer to the all-inorganic perovskite in the precursor formulation is about 0.02:1 to about 0.5:1; and casting the precursor formulation to form a film comprising the all-inorganic perovskite.
In another aspect, light emitting diodes are provided that include an all-inorganic perovskite-based film. The light emitting diodes include an anode; a cathode; and a light emitting layer arranged between the anode and the cathode, wherein the light emitting layer includes an all-inorganic perovskite-based film as provided herein. In some embodiments, the light emitting diode has a photoluminescence quantum yield of at least 50 %, or at least 60 %.
