Fully Printable Halide Perovskite Light-Emitting Diodes
Organometal halide perovskites (Pero) have been well known for their astounding opto-electronic properties and in their utilizations in photovoltaic cells and light emitting diodes (LEDs). They are highly efficient, have low processing temperatures, and are cost effective. For Pero solar cells, the highest power conversion efficiency has reached about 20%, which approaches the best efficiencies of thin film solar cells. With continuing efforts to improve device efficiency and operational stability, the next challenge is to develop Pero solar cells and LEDs using a scalable printing technique to fulfill the promise of large scale, low cost devices.
The present technology is first to develop printed Pero LEDs on rigid indium tin oxide (ITO)/glass and flexible carbon nanotubes (CNTs)/polymer substrates. The devices have ITO or CNTs as the transparent anode, a printed composite film consisting of methyl ammonium lead tri-bromide (Br-Pero) and polyethylene oxide (PEO) as the emissive layer, and printed silver nanowires as the cathode. The printing process can be carried out in air without any deliberate control of humidity; in fact, printing the PEO/Br-Pero in air actually improves its photoluminescence properties. The light intensity, turn-on voltage, and maximum luminescence compare favorably to existing Pero LEDs that are made of multi-layer structures which are formed by more complex fabrication techniques.
For more information, please see publication here.
- Scalable manufacturing of Pero based opto-electronic devices for various surfaces