Photodetectors with High Responsivity by Thickness Tunable Mixed Halide Perovskite Nanosheets

Abstract

Chemical transformation of typically "nonlayered" phases into two-dimensional structures remains a formidable task. Among the thickness tunable CsPbX 3 (X = Br, Br/I, I) nanosheets (NSs), CsPbBr 1.5 I 1.5 NSs with a thickness of ∼4.9 nm have structural stability superior to ∼6.8 nm CsPbI 3 NSs and better hole mobility than ∼3.7 nm CsPbBr 3 NSs. Moving beyond the muchexplored CsPbBr 3 photodetectors, we demonstrate a sharp improvement of the photodetection of CsPbBr 1.5 I 1.5 NS devices by thickening the NSs to ∼6.1 nm through combining 8-carbon and 18-carbon ligand surfactants. Thereby, the responsivity increases up to one of the highest values of 3313 A W −1 at 1.5 V (and 3946 A W −1 at 2 V) with detectivity of 1.6 × 10 11 Jones at 1.5 V, due to the increase in carrier mobility up to 7.9 × 10 −4 cm 2 V −1 s −1 . The better device performance of the NSs than 8.6−13.9 nm nanocubes (NCs) is due to their planarity which facilitates in-plane mobilization of the charge carriers.

Spacer Switched Two-Dimensional Tin Bromide Perovskites Leading to Ambient-Stable Near-Unity Photoluminescence Quantum Yield

“…Metal halide perovskites are a disruptive class of materials because of their potential application in optoelectronics and photovoltaics, − particularly so when they are prepared with minimal structural disorder, high thermal resistance, and photostability. Solution-processed all-inorganic CsPbX 3 (X = Cl, Br, I) nanocrystals (NCs) have reached 100% PLQY because of the synthetic marvels that resulted in a substantial reduction of the nonradiative recombination centers and trap-mediated nonradiative losses .…”

The Perfect Imperfections in Electrocatalysts

“…Powder X‐ray diffraction (XRD) is the primary nondestructive technique that extracts information about the crystal structures, coexistence of multiple phases, lattice doping, atom/ion vacancies, lattice strain, crystallite size, texture, crystal orientations and defects. In particular, Rietveld analysis of the XRD patterns can reveal the atomic scale artefacts that essentially govern the catalyst behavior, [34,50] whereas the compressive lattice strain can be measured using the Williamson‐Hall equation [52] . While XRD provides a global information from the sample, electron microscopy gives a localized data.…”

Synthesis of Size-Controllable Self-Assembled CsPbBr3 Perovskite Nanowires: Implications for Photoemission with Less Recombination

“…As a typical all-inorganic halide perovskite material, CsPbX 3 (X = Cl, Br, I) 1−3 has lead to extensive studies in solar cells, 4 lightemitting diodes (LEDs), 5,6 lasers, 7 photodetectors, 8 and other optical devices 9,10 because of its high photoluminescence quantum yield (PLQY), 11 narrow PL peak, 12 adjustable band gap, 1 high carrier mobility, 13 and facile and diverse synthesize methods. 1,14−16 Among them, CsPbBr 3 is widely applied due to its high stability and moderate band gap (∼2.35 eV).…”

“…As a typical all-inorganic halide perovskite material, CsPbX 3 (X = Cl, Br, I) − has lead to extensive studies in solar cells, light-emitting diodes (LEDs), , lasers, photodetectors, and other optical devices , because of its high photoluminescence quantum yield (PLQY), narrow PL peak, adjustable band gap, high carrier mobility, and facile and diverse synthesize methods. ,− Among them, CsPbBr 3 is widely applied due to its high stability and moderate band gap (∼2.35 eV) . Nanowires (NWs) − have outstanding application prospects in lasing, photodetector, and other specific fields because of their inherently 1-dimensional electronic and photonic nanostructures, for instance, long carrier diffusion lengths and a continuous channel for charge transport .…”