All-Solution-Processed Perovskite Light-Emitting Transistors Enabled by a Fully Organic Architecture

Abstract

CsPbBr₃ perovskite nanocrystals (Pe-NCs) are promising solution-processable emitters for light-emitting devices due to their high brightness, color purity, and photoluminescence quantum yield. However, their integration into more advanced device architectures such as organic light-emitting transistors (OLETs) remains limited by the lack of fully solution-processable platforms that support uniform and compact Pe-NCs emissive layers (EMLs). In this work, we report fully solution-processed Pe-NCs-based LETs (Pe-LETs) using CsPbBr₃ nanocrystals as the emitter. The realization of such a device is enabled by the development of a fully organic LET platform that incorporates: (i) a tailored bilayer gate dielectric of polyvinyl alcohol (PVA) and CyTOP, (ii) a solvent-resistant p-type polymer semiconductor, poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2yl)thieno[3,2-b]thiophene)] (DPP-DTT), and (iii) a nanocomposite EML of Pe-NCs dispersed in a poly(9-vinylcarbazole) and 1,3-bis[2-(4-tert-butylphenyl)1,3,4-oxadiazo-5-yl]benzene (PVK:OXD-7) matrix. Morphological and photophysical characterization, including confocal laser scanning microscopy, drives the optimization of solvent and processing conditions for uniform film formation. Benchmark device substructures are also used to fine-tune the organic platform for effective EML integration. The resulting Pe-LETs exhibit a narrow emission at 509 nm (full width at half maximum, FWHM = 19.2 nm), demonstrating excellent color purity suitable for displays and sensing. A maximum external quantum efficiency of 4.17 × 10⁻³ % is achieved, comparable to state-of-the-art values for inorganic-based LETs.