[2017 07 06] 특별세미나 _Prof. Do Young Kim(Oklahoma State Univ.)

admin | 2017.07.03 10:24 | 조회 25

 

Multi-spectral photo-conversion devices using colloidal PbS nanocrystals

 

 

 

 Date: 2017. 07. 06(Thu) 14:00 ~ 16:30

 Place: Science Building, Room.202 Multimedia Room

■ Speaker: Prof. Do Young Kim(Oklahoma State Univ.)

 Host of a Seminar: Prof. Junwoo Son

 Abstract:

The ability to see, sense, harvest & convert energy over a wide band of the light spectrum, which includes visible, near-infrared (NIR) and shortwave infrared (SWIR), has tremendous value. Commercially-available solar cells and photodetectors do not have infrared sensitivity beyond 1 μm wavelength. While using in the NIR/SWIR wavelengths from 1.0 to 2.0 μm has been made practical by the development of InGaAs based devices, InGaAs based devices are expensive because the epitaxial process used to grow the materials. Furthermore, InGaAs devices have a very low sensitivity in the visible region and thus cannot be used across both the visible and SWIR spectral region. However, colloidal PbS nanocrystals (NCs) with excellent photosensitivity, bandgap tunability, and solution processability provide an attractive material system to realize such inexpensive multi-spectral photo-conversion devices with light sensitivity from UV/Visible to SWIR (350-2000 nm). In this talk, I will discuss recent progress in my research employing colloidal inorganic nanomaterials and organic semiconductors for IR applications. First, I will describe our unique PbS NCs synthesis method to provide unparalleled control of size and uniformity. This method enables synthesis of PbS NCs with excellent particle size control, resulting in well-defined absorption peaks at longer wavelengths up to 2 μm. With the highly mono-dispersed large PbS NCs, we recently demonstrated all-solution processed inorganic multi-spectral (UV-Visible-IR) PbS NCs photodetector with outstanding air-stability and the performance is comparable to epitaxial grown InGaAs photodetectors in terms of noise and detectivity. I will then describe our efforts to investigate a novel IR sensitive organic light emitting diode (OLED), functioning as an IR-to-visible up-conversion device, with a colloidal PbS NC IR sensitizer and an organic visible emitter as an alternative technology for IR imaging. We recently demonstrated a truly low cost IR imaging camera by incorporating the IR sensitive OLED in a commercially available digital single-lens reflex (DSLR) camera.

Dept. of MSE / BK21+

 

 



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