Monolithic Integration of Inorganic Transparent Photonic Crystal as Optoelectronic Gate Dielectric into Organic Light-Emitting Transistor

In organic light-emitting transistors the structural properties such as the in-plane geometry and the lateral charge injection are the key elements which enable the monolithic integration of multiple electronic, optoelectronic and photonic functions within the same device [1]. In this contribution, we report on the realization of hybrid highly-integrated multifunctional optoelectronic organic device by introducing an inorganic high-capacitance photonic crystal [2] as a gate dielectric into a transparent single-layer ambipolar OLET. By engineering the photonic crystal multistack and band gap, we show that the integration of the inorganic photonic structure has a twofold effect on the optoelectronic performance of the device, i.e. (i) to modulate the spectral profile and outcoupling of the emitted light and (ii) to enhance the transistor source-drain current by a 25-fold factor. Consequently, the photonic-crystal integrated OLET showed an order-of-magnitude higher brightness with respect to the corresponding polymer-dielectric device, while presenting as-designed electroluminescence spectral and spatial distribution. Our results validate the efficacy of the proposed approach that is expected to unravel the technological potential for the realization of hybrid highly-integrated optoelectronic smart systems based on organic light-emitting transistors. [1] M. Muccini el al, Laser & Photon. Rev., 6, 2, 258-275 (2012); [2] L. Passoni et al. ACS Nano, 8, 12, 12167-12174 (2014).