Ruddlesden–Popper‐Phase Hybrid Halide Perovskite/Small‐Molecule Organic Blend Memory Transistors

Abstract

Controlling the morphology of metal halide perovskite layers during processing is critical for the manufacturing of optoelectronics. Here, a strategy to control the microstructure of solution‐processed layered Ruddlesden–Popper‐phase perovskite films based on phenethylammonium lead bromide ((PEA)2PbBr4) is reported. The method relies on the addition of the organic semiconductor 2,7‐dioctyl[1]benzothieno[3,2‐b]benzothiophene (C8‐BTBT) into the perovskite formulation, where it facilitates the formation of large, near‐single‐crystalline‐quality platelet‐like (PEA)2PbBr4 domains overlaid by a ≈5‐nm‐thin C8‐BTBT layer. Transistors with (PEA)2PbBr4/C8‐BTBT channels exhibit an unexpectedly large hysteresis window between forward and return bias sweeps. Material and device analysis combined with theoretical calculations suggest that the C8‐BTBT‐rich phase acts as the hole‐transporting channel, while the quantum wells in (PEA)2PbBr4 act as the charge storage element where carriers from the channel are injected, stored, or extracted via tunneling. When tested as a non‐volatile memory, the devices exhibit a record memory window (>180 V), a high erase/write channel current ratio (104), good data retention, and high endurance (>104 cycles). The results here highlight a new memory device concept for application in large‐area electronics, while the growth technique can potentially be exploited for the development of other optoelectronic devices including solar cells, photodetectors, and light‐emitting diodes.

Structures, Properties, and Device Applications for [1]Benzothieno[3,2‐b]Benzothiophene Derivatives

“…[ 247 ] Anthopoulos et al adopted a blending method to incorporate small molecule materials into the preparation of perovskite/small molecule bilayers (Figure 13b). [ 248 ] By adjusting the ratio of (PEA) 2 PbBr 4 and C8‐BTBT, the spontaneous formation of platelet‐like domains of 2D‐(PEA) 2 PbBr 4 was realized by one‐step solution process. The quantum wells formed on the interface played a role of floating‐gate, which could capture the holes.…”

Switched‐On: Progress, Challenges, and Opportunities in Metal Halide Perovskite Transistors

“…This positive development is also accompanied by an overall improvement of device performance, illustrated by the gradual increase in mobility and the emergence of perovskite-based FETs with novel functionalities such as memory. [180,185] Still, many other challenges remain to be addressed, in particular, issues related to device stability, where significantly more research is required.…”

“…In this 2D Ruddlesden‐Popper perovskite, the lead bromide layers separated by the insulating organic cations acted as floating gate and allowed effective trapping/de‐trapping of holes depending on the applied gate voltage. [ 185 ] The authors demonstrated stable performance after over 10 000 read/write cycles with a high operating window. Retention times exceeded 55 000 s and the switching ratio were always above 10 4 .…”

Evolutionary 2D organic crystals for optoelectronic transistors and neuromorphic computing

“…Because of their wide spectral range of optoelectronic responsiveness, flexibility, and vast area processability, OSCs are interesting options for manufacturing high-performance optoelectronic devices and circuits [33,[40][41][42][43]. Reducing the thickness of organic crystals to a few layers or even a single monolayer improves performance in a variety of ways: (i) reduce contact resistance and Schottky barrier so that an ohmic contact can be achieved, as depicted in figures 2(c) and (d) [44][45][46][47], (ii) increase carrier mobility, as shown in figures 2(a) and (b) [45,[48][49][50][51][52][53][54][55][56], and (iii) achieve controllable growth [57]. Apart from the electrical advancements of transistors, obvious enhancement of internal photo-response in the application of 2D OCs-based optoelectronic transistor compared with that of the same bulk crystals, as shown in figures 2(e) and (f) [48].…”