Paul Stavrinou

Abstract:

Metamaterials are a promising new class of materials, in which sub-wavelength physical structures, rather than variations in chemical composition, can be used to modify the nature of their interaction with electromagnetic radiation. Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements. In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films. This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.

Abstract:

Copper thiocyanate (CuSCN) is introduced as a hole‐injection/hole‐transport layer (HIL/HTL) for solution‐processed organic light‐emitting diodes (OLEDs). The OLED devices reported here with CuSCN as HIL/HTL perform significantly better than equivalent devices fabricated with a PEDOT:PSS HIL/HTL, and solution‐processed, phosphorescent, small‐molecule, green OLEDs with maximum luminance ≥10 000 cd m^‐2, maximum luminous efficiency ≤50 cd A^‐1, and maximum luminous power efficiency ≤55 lm W^‐1 are demonstrated.