A Solution‐Processed High‐Performance Phototransistor based on a Perovskite Composite with Chemically Modified Graphenes

Abstract

Phototransistors with a structure of a nitrogen-doped graphene quantum dots (NGQDs)-perovskite composite layer and a mildly reduced graphene oxide (mrGO) layer are fabricated through a solution-processing method. This hybrid phototransistor exhibits broad detection range (from 365 to 940 nm), high photoresponsivity (1.92 × 10 A W ), and rapid response to light on-off (≈10 ms). NGQDs offer an effective and fast path for electron transfer from the perovskite to the mrGO, resulting in the improvement of photocurrent and photoswitching characteristics. The high photoresponsivity can also be ascribed to a photogating effect in the device. In addition, the phototransistor shows good stability with poly(methyl methacrylate) encapsulation, and can maintain 85% of its initial performance for 20 d in ambient air.

Exploring a Polar Two‐dimensional Multi‐layered Hybrid Perovskite of (C5H11NH3)2(CH3NH3)Pb2I7 for Ultrafast‐Responding Photodetection

“…[23][24][25] It is known that the respond.ing rate of photodetector is closely related to its chargetransport dynamics. [26,27] Particularly, high-crystallinity crystals with the low trap density will promote charge-carrier generation and transport properties, and favor to the responding rates. [28][29][30][31] Hence, we attempted to construct crystal-based photodetectors instead of polycrystalline thin-films, [32][33][34][35] and to adopt the lateral-type devices because of their advantage of easy fabrication without transparent electrodes.…”

“…As one of the basic figure‐of‐merits, τ is extremely crucial for some optoelectronic device applications, such as rapid imaging and dynamic monitoring . It is known that the respond.ing rate of photodetector is closely related to its charge‐transport dynamics . Particularly, high‐crystallinity crystals with the low trap density will promote charge‐carrier generation and transport properties, and favor to the responding rates .…”

Highly Oriented Thin Films of 2D Ruddlesden‐Popper Hybrid Perovskite toward Superfast Response Photodetectors

“…Consequently, charge carriers are more conductive along the in‐plane direction of inorganic perovskite layers. Therefore, this will be advantageous to the assembly of fast‐response photodetectors, since response speed is closely bound up with charge transport dynamics . Inspired by such results, highly oriented thin films along the 2D inorganic perovskite layers might be the promising candidates for exploring superfast response photodetector …”

Performance improvement of organic phototransistors by using polystyrene microspheres

“…Besides the photosensitivity, photoresponsivity (R) has also been investigated for our devices, which can be calculated by [31,32]:…”