Boosting Two-Dimensional MoS₂/CsPbBr₃ Photodetectors via Enhanced Light Absorbance and Interfacial Carrier Separation

Abstract

Transition metal dichalcogenides (TMDs) are promising candidates for flexible optoelectronic devices because of their special structures and excellent properties, but the low optical absorption of the ultrathin layers greatly limits the generation of photocarriers and restricts the performance. Here, we integrate all-inorganic perovskite CsPbBr nanosheets with MoS atomic layers and take the advantage of the large absorption coefficient and high quantum efficiency of the perovskites, to achieve excellent performance of the TMD-based photodetectors. Significantly, the interfacial charge transfer from the CsPbBr to the MoS layer has been evidenced by the observed photoluminescence quenching and shortened decay time of the hybrid MoS/CsPbBr. Resultantly, such a hybrid MoS/CsPbBr photodetector exhibits a high photoresponsivity of 4.4 A/W, an external quantum efficiency of 302%, and a detectivity of 2.5 × 10 Jones because of the high efficient photoexcited carrier separation at the interface of MoS and CsPbBr. The photoresponsivity of this hybrid device presents an improvement of 3 orders of magnitude compared with that of a MoS device without CsPbBr. The response time of the device is also shortened from 65.2 to 0.72 ms after coupling with MoS layers. The combination of the all-inorganic perovskite layer with high photon absorption and the carrier transport TMD layer may pave the way for novel high-performance optoelectronic devices.

Ultrahigh Photoresponsive Device Based on ReS2/Graphene Heterostructure

“…As the higher laser power was directed onto the device, a higher photocurrent was generated (Figure S3, Supporting Information). We estimated the responsivity to evaluate the device performance using the following equationwhere PC is the photocurrent and P is the laser power on the channel. The responsivity decreased as the laser power increased, as shown in Figure b.…”

“…We calculated the external quantum efficiency (EQE) and defined the detectivity in the event that the shot noise from dark current dominated the total noise of the photodetector, as followswhere A is the area of the photoactive channel, h is Planck's constant, ν is the frequency of the incident laser, and e is the unit electron charge. According to the results presented in Figure b, the highest EQE and detectivity values were 1.7 × 10 8 % and 1.9 × 10 13 Jones at the lowest power of 15 pW, respectively, as shown in Figure c.…”

Ligand Engineering for Improved All‐Inorganic Perovskite Quantum Dot‐MoS2 Monolayer Mixed Dimensional van der Waals Phototransistor

“…All inorganic halide perovskite CsPbX 3 (X = I, Br, Cl) quantum dots (QDs) have recently emerged as promising candidates for optoelectronic applications such as photovoltaics, light emitters, and photodetectors, because of their tunable optical bandgap high photoluminescence with narrow emission bandwidth, attractive light absorption properties, as well as relatively high stability compared with organic–inorganic hybrid perovskite. Owing to these, considerable efforts have been devoted to breakthroughs of relative optoelectronic devices, especially the sensing devices like flexible X‐ray detectors with a sensitive detection limit of 13 nanograys s −1 and outstanding optoelectronic properties with photoresponsivity of 1.7 × 10 4 A W −1 as recently reported.…”

Metal Halide Perovskites: Synthesis, Ion Migration, and Application in Field‐Effect Transistors

“…If the compatibility issue of solution‐processed MHP nanoplatelets could be fully solved, it can significantly facilitate the processability of MHP nanoplatelets in the transistor application with probable scalable fabrication. This may also add the gate tunability to all the existing two‐terminal photodetectors and planar light‐emitting devices based on MHP nanoplatelets for enhanced device performance . As for large‐size single crystals, the main problem is how to compactly laminate the single crystal onto the transistor substrate.…”