Fabrication of heteromorphic microlens arrays built in the TiO2/ormosils composite films for organic light-emitting diode applications

This paper describes the fabrication of heteromorphic microlens arrays in the polymethyl methacrylate/titanium/organically modified siloxanes photosensitive hybrid films by UV nanoimprint technique and the applications of the prepared microlens arrays on the organic light-emitting diode. The hybrid films were obtained by combining a sol–gel technique and spin coating method. UV–visible spectroscopy and atomic force microscope are used to characterize the properties of the hybrid films, and the results indicate that the hybrid films have high transmittance and small surface roughness. Scanning electron microscope and surface profile results show that the heteromorphic microlens arrays formed in the hybrid films are uniform and well defined. Optical microscopy results show that the hexagonal microlens arrays have the relatively strong focusing ability and excellent imaging performance. Finally, the microlens arrays are applied to the organic light-emitting diode, the luminous properties of the organic light-emitting diode is enhanced, and there is a maximum improvement of about 43.9% in current efficiency for OLEDs with hexagonal microlens arrays. All the results above indicate that it is a simple and low-cost process to fabricate hybrid film microlens arrays by UV nanoimprint technique, and the prepared microlens arrays have potential applications in the organic light-emitting diode.