In Situ Inkjet Printing Patterned Lead Halide Perovskite Quantum Dot Color Conversion Films by Using Cheap and Eco‐Friendly Aqueous Inks

Abstract

Inkjet‐printed perovskite quantum dot (PQD) color conversion films (CCFs) have great potentials for mini/micro‐LED displays because of their ultrahigh color purity, tunable emissions, high efficiency, and high‐resolution. However, current PQD inks mainly use expensive, toxic, and flammable organic substances as solvents. In this work, water is proposed to be used as the solvent for inkjet printing PQD/polymer CCFs. The green‐emitting patterned MAPbBr3/polyvinyl alcohol (PVA) films are in situ prepared by using halides and the PVA‐based aqueous ink. The as‐printed CCFs exhibit a high‐resolution dot matrix of 90 µm with a bright green emission (λem = 526 nm), a high photoluminescence quantum yield of 85%, and a narrow full width at half maximum of 22 nm. They have both air‐ and photo‐stabilities under ambient conditions, and each pixel of CCFs is relatively uniform in morphology and fluorescence when the substrate temperature is 80 °C. The patterned blue‐emitting MAPbClxBr3‐x/PVA and red‐emitting Cs0.3MA0.7PbBrxI3‐x/PVA can also be printed by aqueous inks. These results indicate that the designed aqueous inks are promising for in situ inkjet printing high resolution and reliability PQD CCFs for mini/micro‐LED displays.

An overview on the principle of inkjet printing technique and its application in micro-display for augmented/virtual realities

“…To date, inkjet printing techniques have been used to deposit QDs directly onto the chip surface 15 or onto a transparent substrate, forming a pattern that covers the chip array. According to the different strategies of driving the ink, there are aerosol inkjet printing (AJP) 16 , piezoelectric inkjet printing (IJP) 17,18 , and electrohydrodynamic (EHD) inkjet printing 19 . All these strategies, by exerting some external forces, eject the ink through the nozzle.…”

“…The surface tension of the mixed solvent with 20 vol % 1,2-dichlorobenzene and 80 vol % cyclohexylbenzene reduced to 31.77 43 , John Wiley and Sons; (c) ref. 17 , American Chemical Society; (d-f) ref. 91 , AIP Publishing.…”

“…10(c)]. Therefore, it is not easy to obtain a smooth pattern with a small line width or diameter by adjusting the rheological parameters of the ink in a pure solvent ink system without polymer 17 .…”

Classifications and Applications of Inkjet Printing Technology: A Review

“…Perovskite quantum dots (PQDs) have become a significant area in display technology research owing to their distinct optical properties, including a tunable wavelength and narrow wavelength [199]. Shi et al [200] inkjet-printed PQD inks with water as a solvent. Yoo et al [201] printed with a perovskite ink on an ethyl cellulose film and concluded that a (3-aminopropyl) trimethoxysilane (APTES)-coated red perovskite ink had improved drying stability.…”

Microscale Perovskite Quantum Dot Light‐Emitting Diodes (Micro‐PeLEDs) for Full‐Color Displays

“…As a rule of thumb, a range of 1 < Z < 14 is considered suitable for IJP. [45] Cyclohexylbenzene is selected as a suitable solvent for the ink, which can maintain the excellent luminescence performance of the PeQDs and exhibit a good IJP (Figure S6, Supporting Information) ability with a Z value of 9.02 (e.g., the nozzle diameter is 20 μm, the density is 0.96 g mL −1 , the surface tension is 35.69 N m −1 , and the viscosity is 2.9 cP). The structure of PeLEDs typically consists of a multilayer of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/poly(9-vinylcarbazole) (PVK)/PeQD/1,3,5-tris(1phenyl-1H-benzimidazol-2-yl)benzene (TPBi)/LiF/Al.…”