Proceedings Article | 17 September 2018
KEYWORDS: Perovskite, Thin films, Crystals, Crystallography, Optoelectronics, Thermography, Luminescence, Quantum efficiency, Nanoimprint lithography, Photonic nanostructures
Halide perovskites are currently of interest for a variety of optoelectronic applications. While, typical wet-chemical preparation techniques afford relatively rough polycrystalline layers, we have recently demonstrated that thermal imprint is a powerful post-deposition processing tool that affords extremely smooth perovskite thin-films with crystals that extend over tens of microns laterally.[1,2] A comparative study of optical, morphological and thermal properties (e.g. thermal conductivity) reveals some striking similarity of pressed MAPbX3 thin-films and their single crystalline analogues.[3] More recently, we successfully used thermal imprint also for entirely inorganic halide perovskite materials, such as CsPbBr3. While as-deposited CsPbBr3 layers are typically discontinuous and rough with a large number of pinholes, thermal imprint at relatively low temperature and pressure (150°C, 100 bar) will be shown to turn them into dense, smooth and pinhole-free thin films, which show substantially enhanced luminescence quantum yield and in contrast to pristine CsPbBr3 layers even enable room-temperature amplified spontaneous emission (ASE). Perovskite thin films patterned by thermal nanoimprint with photonic resonator structures will be shown to afford hybrid and entirely inorganic distributed feedback lasers, with ultra-low lasing thresholds.[2,4]
[1] A. Mayer et al. J. Vac. Sci. & Techol. B 2017, 35, 06G803.
[2] N. Pourdavoud et al. Adv. Mater. Technol. 2018, 3, 1700253.
[3] R. Heiderhoff et al. J. Phys. Chem. C 2017, 121, 28306.
[4] N. Pourdavoud et al. Adv. Mater. 2017, 29, 1605003.
