광전자나노소재및소자연구실

ONL focuses on fundamental principle of optoelectronic nanomaterials to apply them to novel, high performance optoelectronic devices, for instance, light-emitting diodes, solar cells, photo-detectors, and so forth. Our research efforts span across three research branches from wet chemistry of semiconductor materials (Thrust 1), optical spectroscopy (Thrust 2), to architecture design and physics of optoelectronic devices (Thrust 3). Not only in-depth research on each thrust, we also combine them in multilateral way to reach our ultimate goal. Figure 1| Wet chemistry of semiconductor nanocrystals (NCs) and quantum confinement effect. (left) Colloidal semiconductor NCs are made in solution phase using specially designed setup, so-called Schlenk line. (middle) NCs exhibit unique quantized electronic states as their size becomes comparable or smaller than exciton Bohr radius, a barometer of exciton size. Decrease in size increases energy difference between lowest electron and hole states, which is translated into the increment of band gap of NCs. (right) As well as size, morphology of NCs also influences electronic structure of semiconductor NCs. Dots, rods and tetrapods are one of representative shapes successfully made by wet chemistry. When size of semiconductor NCs is reduced below a certain level, they feature unique optical and electronic properties that are not observed in bulk materials. Most well-known and unique phenomenon is the quantum confinement effect, an increment of band gap with a decrement of size. Based on this phenomenon, controlling their chemical composition and shape open us new pathway to manipulate their optoelectronic properties as we demand. For example, we can full-color luminescence materials emitting from ultraviolet to near infrared emission j