Photonic nanopatterns in organo-metal halide perovskites by thermal nanoimprint lithography (Conference Presentation)

The recently re-discovered class of organometal-halide perovskites hold great promise for solar cells, LEDs and lasers.[1] Today, their potential has not been fully unlocked partially because of the lack of suitable nano-patterning techniques, which are mandatory to create resonator structures, waveguides etc. with a maximum level of precision directly into perovskite layers. Their chemical and thermal instability prevents the use of established wet-chemical patterning techniques.[2] In contrast to conventional inorganic semiconductors, crystal binding in these perovskites includes significant contributions of van der Waals interactions among the halide atoms and Hydrogen bonding.[3] The formation enthalpy per unit cell is only about 0.1eV in MAPbI3.[4] Here, we take advantage of the “soft-matter properties” of organo-metal halide perovskites and demonstrate that photonic nano-structures can be prepared by direct thermal nano-imprint lithography in MAPbI3 and MAPbBr3 at relatively low temperatures (<150°C). The resulting periodic patterns provide distributed feedback resonators, which afford lasing in MAPbI3 with ultra-low threshold levels on the order of 1 μJ/cm2.[5] Moreover, our results also state the first DFB lasers based on MAPbBr3. We will discuss the applicability of thermal imprinting for perovskite solar cells and LEDs. [1] B. R. Sutherland et al. Nat Photon 2016, 10, 295. [2] D. Lyashenko et al. physica status solidi (a) 2017, 214, 10.1002/pssa.201600302. [3] D. A. Egger et al. Journal of Physical Chemistry Letters 2014, 5, 2728. [4] A. Buin et al. Nano Lett 2014, 14, 6281. [5] N. Pourdavoud et al. Adv Mater 2017, 10.1002/adma.201605003.