A self-powered photoelectrochemical ultraviolet photodetector based on Ti₃C₂T _x /TiO₂ in situ formed heterojunctions

Abstract

Transition metal carbides and nitrides (MXenes), as a large family of emerging two-dimensional materials, have demonstrated extraordinary performance in many fields such as electronics, optics and energy storage. However, their susceptibility to oxidation during preparation and storage in ambient air environment is undesirable for long-term and stable applications. Here, we have demonstrated that the spontaneous oxidation of Ti3C2T x can be harnessed ingeniously to prepare Ti3C2T x /TiO2 in situ formed heterojunctions. Furthermore, a self-powered ultraviolet photodetector was constructed based on the photoelectrochemical performance of Ti3C2T x /TiO2 heterojunctions. Since the highly conductive Ti3C2T x can promote the separation and transfer of photogenerated carriers in TiO2, the prepared photodetector exhibits high responsivity (2.06 mA W−1), short rise and decay times (45 and 69 ms) and long-term stability. This work demonstrates the controllable synthesis of Ti3C2T x /TiO2 heterojunctions and provides a new promising potential of MXenes for photodetection applications.

Ultra‐High Speed, High‐Sensitivity Spin‐Cast MXene‐Semiconductor‐MXene Photodetectors

“…Both pulse widths, that are in the range of 8-154 ps, and fall times (400-800 ps range), are orders of magnitude shorter than in similar devices that were previously reported. [19,[34][35][36][37][38][39][40][41][42][43][44][45]47] Figure 3d shows the impulse response of the device under +10 V bias, as the illumination power is swept from 16 to 88 µW. A double exponential model consisting of a fast and a slow component fits this data well (Table S3., Supporting Information).…”

“…[69][70][71][72] The presented data shows that this BE/MX-S-MX device is orders of magnitude faster than other 2D devices. Figure 6 compares the responsivity and time response of previously reported MXene based devices that include TiO 2 , [34,35] CsPbBr 3 , [36,37] GaN, [38,39] Bi (with Nb 2 C), [40] MoS 2 , [41] n-Si, [43] InSe, [44] GaAs, [26,47] ZnO, [46] and Ge, [45] as well as other devices such as MoS 2based, [42] Graphene, [19] and Graphene/Si [73] ones. The response of our BE/MX-S-MX device shows excellent responsivity, and time response by simultaneously optimizing the 2D contact with semiconductor structure (Figure 6).…”

“…The authors declare no conflict of interest. [34,35] CsPbBr 3 , [36,37] GaN, [38,39] Bi (with Nb 2 C), [40] MoS 2 , [41] n-Si, [43] InSe, [44] GaAs, [26,47] ZnO, [46] and Ge, [45] as well as other devices such as MoS 2 -based, [42] Graphenebased, [19] and Graphene/Si [73] ones. Inset compares MX-GaAs-MX and BE/MX-S-MX on a linear scale.…”

High‐Performance Ultraviolet Photodetectors Enabled by van der Waals Schottky Junction Based on TiO2 Nanorod Arrays/Au‐Modulated Ti3C2Tx MXene

“…A few works have reported the combination of TiO 2 with MXenes in UV PDs. Wang et al [31] utilized the spontaneous oxidation of Ti 3 C 2 T x to prepare Ti 3 C 2 T x /TiO 2 in situ forming 2D-3D heterojunctions, which exhibited a responsivity of 2.06 mA W −1 at 0 V (360 nm, 48.5 µW cm −2 ). The rise/decay time was 45 and 69 ms. Yang et al [32] demonstrated a controllable in situ-oxidation strategy for large-scale 3D-networked Ti 3 C 2 T x -TiO 2 heterostructure for PDs, the responsivity of which achieved 0.06 mA W −1 at 5 V (405 nm, 8.58 mW cm −2 ).…”

Emerging applications of MXenes for photodetection: Recent advances and future challenges

“…SEM results also confirm the formation of titanium oxide (TiO 2 ) nanoparticles on un-delaminated MXenes which are stored at ambient environments [142]. Fortunately, a new strategy by controlling the oxidation process of MXenes has been investigated by several groups, which overturns the aforementioned oxidation disadvantage and further improves the device performances [124,134,143]. In 2018, Chertopalov et al demonstrated that partially oxidized Ti 3 C 2 MXene thin films exhibit obvious photoresponse in the UV region (Fig.…”