Strong Photocurrent from Solution‐Processed Ruddlesden–Popper 2D Perovskite–MoS₂ Hybrid Heterojunctions

Abstract

This study reports overall improvement in structural, morphological, and optoelectronic properties of Ruddlesden-Popper (RP) perovskites of type (BA) 2 (MA) n−1 Pb n I 3n+1 by forming their bulk heterojunction hybrids with fewlayer MoS 2 nanoflakes. RP perovskite-MoS 2 hybrid thin films have shown significantly improved packing and crystallinity compared to pristine perovskites. The presence of MoS 2 at RP perovskite interface has improved the quantum confinement effects and transport of photogenerated charge carriers from perovskite to MoS 2 , due to suitable conduction band of MoS 2 and more number of decay channels. The optoelectronic properties of RP perovskite-MoS 2 hybrids are studied for various MoS 2 concentrations (4.2-25.6 × 10 −3 m) and at optimum concentration (12.8 × 10 −3 m) the photodetectors (n = 2, 4) have shown strong, sharp, and highly stable photocurrent response. At 0.0 V bias, the RP perovskite (n = 4) and MoS 2 (12.8 × 10 −3 m) hybrid-based photodetectors, prepared without any encapsulation, have shown strong photocurrent density of ≈9.8 µA cm −2 under 1 sun illumination, which is ≈17 times higher compared to the pristine RP perovskites-based photodetector (0.6 µA cm −2 ). Further transient photocurrent, performed over 200 cycles for hybrid (n = 4+MoS 2 ) thin film photodetector under laser (λ ex ≈ 405 nm, ≈630 mW cm −2 ) illumination and ambient air conditions has shown highly stable photocurrent with only ≈9.6% reduction in the peak photocurrent density.

Smallest Organic Spacers-Based Ruddlesden–Popper and Dion–Jacobson Perovskites: Which One Is Better for Optoelectronics?

“…However, the difference between the ε eff of RP-EA and MAPbI 3 is relatively lower; therefore, no sharp exciton peaks at all are observed in their absorption spectra. These correlations also match well with the difference between the ε eff of RP-BA ( n = 1–4) perovskites and that of MAPbI 3 , which shows narrow absorbance peaks in the spectra . It must be noted that the variation of ε eff for RP-BA perovskites with n value is following an inverse trend due to the fact that ε b for BA is ∼4.92, which is lower than the ε w ≈ 6.5 for the PbI 4 octahedrons.…”

“…These correlations also match well with the difference between the ε eff of RP-BA (n = 1−4) perovskites and that of MAPbI 3 , which shows narrow absorbance peaks in the spectra. 39 It must be noted that the variation of ε eff for RP-BA perovskites with n value is following an inverse trend due to the fact that ε b for BA is ∼4.92, which is lower than the ε w ≈ 6.5 for the PbI 4 octahedrons. Due to large dielectric value of the EDA organic spacer (ε b ≈ 15 compared to EA ε b ≈ 6.9, it is expected that the exciton binding energy for DJ-EDA perovskites is relatively lower than that for the RP-EA perovskites.…”

High Performance Photorechargeable Li‐Ion Batteries Based on Nanoporous Fe2O3 Photocathodes

“…Photocurrent response of pristine Fe 2 O 3 and composite films is studied by fabricating vertical configuration photodetectors (PDs), see the Experimental Section for details. [48,49] The transient photocurrent response was recorded using the potentiostat, and a standard Xe-lamp light source (100 mW cm −2 ) was used to illuminate the PD periodically by controlling the shutter manually. [50] Figure 2c shows the photocurrent response of pristine PD (FTO/Fe 2 O 3 /Al).…”

PCBM Functionalized WS2 Hybrid Nanostructures for High Performance Li-Ion Battery Anodes: Toward Binder-Free Electrodes

“…Liquid phase exfoliation method is adopted to fabricate the WS 2 nanoflakes using bulk WS 2 powder as the precursor .…”

“…Liquid phase exfoliation method is adopted to fabricate the WS 2 nanoflakes using bulk WS 2 powder as the precursor. 63 N-Methyl-2-pyrrolidone (NMP) was used as solvent throughout the exfoliation process as it has a high boiling point (202 °C) as well as high surface tension (40.79 mJ m −2 at 20 °C). 64 Here, 40 mg of bulk WS 2 powder was uniformly dispersed in 2 mL of NMP solvent in a glass vial using ultrasonication (Labman LMUC-3, power 100 W, 40 kHz) step.…”