Changhee Lee, Ph.D.

Semiconductor nanoparticles such as colloidal quantum dots (QDs), nanorods, and tetrapods have very attractive electronic and optical characteristics for optoelectronic devices such as bandgap tenability, wide absorption and narrow emission spectral bandwidth. However, it is difficult to fabricate uniform nanoparticle films using solution-processes such as spin-coating or inkjet printing due to massive aggregation of nanoparticles. Here, we demonstrate that the hybridization of nanoparticles with conducting polymers can overcome this problem because of the improved colloidal stability and the flexible processing capability of the hybrids originating from chemically grafted polymer brushes. Therefore, the polymer-nanoparticle hybrids have advantages of both materials (i.e., optical and electrical properties from nanoparticles and processability originating from polymers). The light-emitting diodes (LEDs) employing the polymer-QD hybrid film as the active layer shows much improved performance compared to devices with colloidal QDs since charge carrier injection can be facilitated at the interface between QDs and conducting polymer brushes. In addition, the P3HT:CdSe QD hybrid solar cell shows a promising power conversion efficiency of about 2 %.