Nanostructured Ruddlesden–Popper-Layered Lead Bromide Perovskites with Stable and Selected Wavelength for Photodetection Applications

Abstract

Success in photovoltaic power generation has raised a huge possibility in metal halide perovskites to exhibit excellent photodetection performance with the same physics of photocarrier generation, and their collection at terminal electrodes is employable with less defect-assisted carrier recombination loss. To test this, nanostructured Ruddlesden–Popper (RP)-layered perovskite series were synthesized based on a cyclic organic moiety and Br– halide, resulting in (CH)2(MA) n−1Pb n Br3n+1 [where CH2-(1-cyclohexenyl) ethylamine, MAmethylammonium, Brbromine, and n = 1–4], to explore how best its mono-to-few layer (n) 2D and quasi 2D-structures can offer photodetection performance with maximum absorbance in the unexplored blue-to-green band gap RP perovskites with maximum stability. Thermogravimetric analysis revealed that the very stable nature of these RP perovskites is accompanied by a linear rise in the structural phase transition temperatures, which range from 270 °C (CH)2PbBr4 (n = 1) to 304 °C (CH)2(MA)3Pb4Br13. The RP perovskites (CH)2(MA) n−1Pb n Br3n+1 (n = 1–4) demonstrated sharp exciton emission peaks from blue (∼408 nm) to green (∼528 nm). The X-ray diffraction results confirmed the highly crystalline nature of quasi-2D perovskite thin films. Layer-dependent photoluminescence studies exhibit strong room-temperature exciton photoluminescence and high carrier lifetime. The transient photocurrent measurements for (CH)2(MA)3Pb4Br13 (n = 4) RP perovskite thin films show nearly six times the bias voltage changed from 1 to 5 V at 405 nm laser light excitation. In addition, with respect to performance, the (CH)2(MA)3Pb4Br13 photodetector has shown the highest responsivity (67.2 mA/W), ultrafast transient photocurrent response (122 nA), and high EQE (20.6%) as compared to (CH)2(MA)2Pb3Br10 (n = 3) and (CH)2(MA)Pb2Br7 (n = 2) in ambient temperature.

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

“…The τ 1 for DJ-EDA perovskites ( n = 1, 2) is found to be higher than for RP-EA ( n = 1, 2), which suggests longer recombination lifetimes in the DJ perovskites compared to RP perovskites; however, τ 2 is found to be similar for both RP and DJ ( n = 1, 2) perovskites, which suggest similar charge transfer rates across these samples. The enhanced photo charge carrier lifetime for the DJ-EDA compared to RP-EA perovskites is attributed to the reduced exciton binding energies of DJ-EDA perovskites compared to RP-EA perovskite thin films, which can also be explained by investigating the dielectric properties of both RP and DJ perovskites. , Moreover, the rise in the lifetimes with the increase in the inorganic layers ( n value) also confirms the formation of quasi-2D RP and DJ perovskites …”

“…In order to determine the photocurrent response of the RP-EA and DJ-EDA perovskites, a lateral photodetector prototype (FTO/perovskite/FTO), see device configuration schematics in Figure a, is fabricated by making a uniform scratch on a FTO coated glass substrate using a diamond cutter tool followed by substrate cleaning steps. , The channel length of the device is estimated from SEM images, which is found to be ∼150 μm (Figure a, inset image). To fabricate the photodetectors of RP-EA and DJ-EDA perovskite ( n = 1–4), the corresponding perovskite films are drop-casted, using 1 M and a fixed volume of precursor solutions, on the scratched FTO substrate in order to uniformly fill up the channel area (see Methods section for more details).…”

“…In 2021, Gao et al fabricated a novel series of DJ perovskites using short aromatic spacer mPDA (m-phenylenediammonium), possessing a short I···I interlayer distance (4.00–4.04 Å) due to the compact size of the spacer, which influences the structural and optoelectronic properties of DJ perovskites . As we previously reported, the aromatic organic spacer-based RP perovskites are known for improved optical properties, as well as thermal and structural stabilities. , …”

“…16 As we previously reported, the aromatic organic spacer-based RP perovskites are known for improved optical properties, as well as thermal and structural stabilities. 17,18 So, as studied so far, changing the organic spacer significantly alters the structural, optical, and optoelectronic properties. The size, shape, and location of the ammonium group of organic spacers influence the dielectric and quantum confinement, which significantly changes the fundamental properties.…”

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

“…The lifetimes of photogenerated charge carriers in the pristine Fe 2 O 3 and Fe 2 O 3 -PCBM-MWCNT composite films are obtained by performing the time resolved photoluminescence (TRPL) spectroscopy using the time-correlated single-photon counting (TCSPC) method. [45,46] The film sample, prepared on a glass substrate, is positioned within the integrating sphere and irradiated with a 401 nm excitation wavelength pulsed diode laser in the reflection mode to capture the emission signal (𝜆 PL ≈612 nm). The emission signal is fed to the monochromatic coupled photomultiplier tube (PMT) based picosecond photon detection (PPD) module to get the time-resolved PL decay curves shown in Fig- ure 2b.…”