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(Bern, Switzerland - Alvin Wei-Cheng Wong)



- Optoelectronics

Opto-electronics (or optronics) is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation. Important applications of optoelectronics include: Optocoupler, Optical fiber communications

Optoelectronics is based on the quantum mechanical effects of light on electronic materials, especially semiconductors, sometimes in the presence of electric fields.

  • Photoelectric or photovoltaic effect, used in: photodiodes (including solar cells), phototransistors, photomultipliers optoisolators, integrated optical circuit (IOC) elements
  • Photoconductivity, used in: photoresistors, photoconductive camera tubes, charge-coupled imaging devices 
  • Stimulated emission, used in: injection laser diodes, quantum cascade lasers 
  • Lossev effect, or radiative recombination, used in: light-emitting diodes or LED, OLEDs 
  • Photoemissivity, used in: photoemissive camera tube


- Perovskite quantum dots (PQDs) 

Perovskite quantum dots (PQDs) are semiconducting nanocrystals with diameters of 2-10 nanometers. They have unique properties that make them useful in many optoelectronics areas, such as: 

  • Light-emitting diodes
  • Lasers
  • Photodetectors
  • Solar cells

PQDs have several properties, including:

  • High defect tolerance
  • Quantum size effects
  • Near perfect photoluminescent quantum yield
  • Organic-inorganic hybrid structure

PQDs can be classed as:

Organic-inorganic hybrid, where A is an organic cation such as methylammonium (MA) or formamidinium (FA), or fully inorganic (A=Cs)
Mixed halide perovskites, where X is a mixture of Cl/Br or Br/I

For visible optoelectronic applications, the nanocrystals are generally synthesized to have a size of 4 – 15 nm. 

Scientists at Australia's University of Queensland set a new world efficiency record for a quantum dot solar cell. The group fabricated a 0.1cm² device from a perovskite material and measured power conversion efficiency at 16.6%.


[More to come ...]

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