Colloidal Quantum Dot Light Emitting Diodes at Telecom Wavelength with 18% Quantum Efficiency and Over 1 MHz Bandwidth

• DOI: 10.1002/advs.202200637
• Publication Date: 2022-05-05T02:15:00Z
• Authors: Santanu Pradhan; Mariona Dalmases; Nima Taghipour; Biswajit Kundu; Gerasimos Konstan...
• Keywords: Quantum Efficiency

Developing high performance, low-cost solid-state light emitters in the telecom wavelength bandwidth is of paramount importance for infrared light-based communications. Colloidal quantum dot (CQD) based emitting diodes (LEDs) have shown tremendous advances recent times through improvement synthesis chemistry, surface property, and device structures. Despite advancements CQD LEDs visible range with efficiency reaching theoretical limits, their short-wave (SWIR) counterparts mainly on lead chalcogenide CQDs, lower performance (≈8%). Here authors report highly efficient SWIR a recorded EQE 11.8% enabled by use binary matrix comprising QD populations different bandgaps at emission 1550 nm. By further optimizing optical out-coupling via hemispherical lens to reduce waveguide loss, LED increased 18.6%. The has an electrical 2 MHz, which motivated them demonstrate its first free-space transmission link entirely technology (photodetector emitter) opening new window applications optoelectronics.