Tuning the Electrical Performance of 2D Perovskite Field‐Effect Transistors by Forming Organic Semiconductor/Perovskite van der Waals Heterojunctions

Abstract

the performance of semiconductor devices. In conventional silicon-based devices, doping is widely employed as an effective way to tune the device performance. In general, doping can tune the electrical properties of semiconductors such as carrier density, Fermi level, and mobility to optimize device performance. [1] Typically, a higher hole density is obtained for p-doped Si, and a higher electron density is obtained for n-doped Si. [2] In recent years, new semiconductors have flourished, such as 2D semiconductors, [3] organic semiconductors (OSCs), [4] perovskite semiconductors, [5] etc. Among them, perovskite semiconductors have been heavily studied for their excellent optoelectronic property, especially in the field of solar cells and light-emitting devices. In addition, perovskite semiconductors are also quite promising in the application of FETs due to their high intrinsic mobilities over 100 cm 2 V −1 s −1 measured by terahertz techniques. [6] However, obtaining perovskite FETs that can function well at room temperature is challenging, which is attributed to the partially screened gate electric field by ion migration. [7] 2D Ruddlesden-Popper perovskites are considered an exceptional option to alleviate the ion migration problem due to their unique layered structures, where bulky organic chains can inhibit the ion migration along the direction perpendicular toThe development of techniques for tuning/controlling the properties of electronic devices such as field-effect transistors (FETs) is important for the optimization of device performance or the realization of custom-designed device functions. Here, a simple method for tuning the performance of 2D perovskite ((PEA) 2 SnI 4 ) FETs by transferring organic semiconductor PDVT-10 films onto (PEA) 2 SnI 4 films to form van der Waals heterojunctions (vdWHs) is presented. By varying the electrical properties of PDVT-10 with doping technique, the performance of (PEA) 2 SnI 4 FETs can be effectively tuned in terms of on-state current, threshold voltage, and mobility, with mobility increased from 0.10 cm 2 V −1 s −1 for pristine (PEA) 2 SnI 4 FETs to 0.46 cm 2 V −1 s −1 for the vdWH-based FETs. This phenomenon can be attributed to the holes transfer occurring at heterojunction interface. More interestingly, the performance of the (PEA) 2 SnI 4 FETs can be almost fully recovered once the PDVT-10 films are removed, indicating the reversibility of the method. Such method of tuning semiconductor device performance by forming vdWHs can be also extended to other semiconductors and devices.

Molecular Doping Enabling Mobility Boosting of 2D Sn2+‐Based Perovskites

“…[12] Most recently, the significant progress in the optimization of perovskite synthesis and deposition rekindled the research interest in this class of materials to achieve improved device performance and stability. [9,[13][14][15][16][17] Despite these advances, the insulating characteristic of the organic spacer blocks efficient charge transport with a low charge carrier mobility. In addition, the large size of the organic spacer restricts the free holes in 2D Sn 2+ -based perovskites owing to the relatively high tin vacancy (V Sn ) formation energy from weakened Sn 5s-I 5p antibonding.…”

A Methodology of Fabricating Novel Electrodes for Semiconductor Devices: Doping and Van der Waals Integrating Organic Semiconductor Films

“…The preparation of (PEA) 2 SnI 4 films was described in the experimental section, and the procedures for transferring DOSCF electrodes are the same as shown above. [23,32] It turns out that the DOSCF device shows an average mobility of 0.97 cm 2 V −1 s −1 , which is far higher than that of the control device with evaporated Au film as electrodes (average mobility of 0.44 cm 2 V −1 s −1 ). This is possibly because the evaporation of Au causes damages to the perovskite lattice or results in chemical interaction, while the vdW contacts made by DOSCFs avoid such problems.…”

“…In this study, we used a benzobisthiadiazole (BBT)-based D-A copolymer PBBT-2T as the host p-type semiconductor (see Figure 1a), and a highly efficient p-dopant trityl tetrakis(pentafluorophenyl) borate (TrTPFB) which can significantly enhance the conductivity of various semiconductors with little disruption to the film structure/morphology as the dopant. [23][24][25][26][27] To characterize the electrical properties of PBBT-2T, bottomgate top-contact (BGTC) devices with Au electrodes were fabricated, whose transfer and output characteristics are illustrated in Figure 1b,c, respectively. These results show PBBT-2T is a p-type semiconductor with hole mobility of ≈0.1 cm 2 V −1 s −1 .…”

2D Ruddlesden–Popper Polycrystalline PerovskitePyro‐Phototronic Photodetectors

“…The family of two-dimensional (2D) layered halide perovskite has emerged as a promising photoelectric material due to its unique structure, optoelectronics properties, and cost-effective solution fabrication technology, [1][2][3] and it has been widely used in the fields of solar cells, [4,5] light-emitting diodes, [6] field-effect transistors, [7] and photodetectors (PDs). [8][9][10] Among them, 2D Ruddlesden-Popper (RP) perovskite is attracting much attention because of its superior environmental stability, mature preparation technology, good reproducibility, and excellent performance in photovoltaics.…”