Guided Formation of Large Crystals of Organic and Perovskite Semiconductors by an Ultrasonicated Dispenser and Their Application as the Active Matrix of Photodetectors

Abstract

The crystallization of organic or perovskite semiconductors reflects the intermolecular interactions and crucially determines the charge transport in opto-electronic devices. In this report, we demonstrate and investigate the use of an ultrasonicated dispenser to guide the formation of crystals of organic and perovskite semiconductors. The moving speed of the dispenser affects the match between the concentration gradient and evaporation rate near the three-phase contact lines and thus the generation of various crystallization morphologies. The mechanism of crystallization is given by a relationship between the calculated concentration gradient profile and the degree of crystal alignment. Highly ordered, aligned crystals are achieved for both organic bis­(triisopropylsilylethynyl)-pentacene and perovskite MAPbI3 semiconductors. Absorption spectra, Raman scattering spectroscopy analysis, and grazing incidence wide-angle X-ray scattering measurement reveal the strong anisotropy of the crystalline structures. The aligned crystals lead to remarkably enhanced electrical performances in an organic thin-film transistor (OTFT) and perovskite photodetector. As a demonstration, we combine the OTFT with photodetectors to achieve an active matrix of normally off, gate-tunable photodetectors that operate under ambient conditions.

A Direct Writing Approach for Organic Semiconductor Single‐Crystal Patterns with Unique Orientation

“…The d ‐spacing calculates at 2θ ≈ 5.48° is 1.611 nm, which is almost identical to the spacing of D (100) in the single crystal of TIPS–pentacene (1.68 nm). [ 13 ] This result shows that the c ‐axes of the crystals are perpendicular to the substrate. As shown in Figure S10c, Supporting Information, the different regions in the crystal arrays show similar XRD patterns, indicating high consistency of the whole patterns.…”

“…Meanwhile, along the [210] crystallographic axis in the single crystals, the π−π stacking distance is the smallest one and the distances between (210) planes are approximate 0.36 nm, corresponding to the π−π stacking distance. [ 13 ] The [210] crystallographic axis is the electronic transport direction. These results all reveal that TIPS–pentacene crystal patterns are single crystals with unique orientation.…”

Inkjet‐Printed, Wafer‐Scale Organic Schottky‐Gate Transistors toward Single‐Battery‐Driven Integrated Logic

“…Note that unlike conventional inkjet printing, which drips discrete droplets from the nozzle onto the substrate under pressure, we utilized ultrasonic vibration-controlled dispensing combined with antisolvent crystallization methods, enabling liquid meniscus formation between the substrate and micropipette for the stable and continuous crystallization of organic semiconducting films (Figure S2a-c, Supporting Information). [18,22,23] Subsequently, we characterized the crystalline properties of the printing films via cross-polarized optical microscopy. As the substrate rotates horizontally, the colors of the films obviously change from bright to dark, indicating few grain boundaries within the printing films (the upper panel of Figure 1d).…”

Emerging Intelligent Manufacturing of Metal Halide Perovskites

“…[99] Third, printing parameters greatly influence perovskite crystal formation and the printing process. [100][101][102] As the pulling speed increases from 5 to 20 µm s −1 during the 3D printing of freeform perovskite nanostructures (Figure 4f), a printed MAPbI 3 perovskite hollow nanotube with an outer diameter of 1140 nm and an inner diameter of 360 nm will transform into a solid nanowire because the meniscus is downsized by stretching. [35] By splitting inks into micro droplets via ultrasonic or pneumatic atomization, aerosol jet printing becomes a feasible method for printing ink with viscosities ranging from 1 to 1000 cp.…”