Formation of aligned periodic patterns during the crystallization of organic semiconductor thin films

Bangsund, John S.; Fielitz, Thomas R.; Steiner, Trevor J.; Shi, Kaicheng; Sambeek, Jack R. Van; Clark, Catherine P.; Holmes, Russell J.

doi:10.1038/s41563-019-0379-3

Cited by 48 publications

(38 citation statements)

References 48 publications

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“…In particular, non‐equilibrium routes to metastable states could unveil patterns not seen in equilibrium states. Thus, an understanding of crystallization phenomena is the key to lock into place materials with morphologies and/or functionalities not present in equilibrium states . Particularly appealing are spiral eutectics, mixtures of two or more solid phases that grow simultaneously from a parent liquid phase and which arrange into intricate spiraling patterns, in some cases akin to a DNA helix.…”

Section: Introductionmentioning

confidence: 99%

Multi‐Step Crystallization of Self‐Organized Spiral Eutectics

Moniri

Bale

Volkenandt

et al. 2020

Small

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A method for the solidification of metallic alloys involving spiral self‐organization is presented as a new strategy for producing large‐area chiral patterns with emergent structural and optical properties, with attention to the underlying mechanism and dynamics. This study reports the discovery of a new growth mode for metastable, two‐phase spiral patterns from a liquid metal. Crystallization proceeds via a non‐classical, two‐step pathway consisting of the initial formation of a polytetrahedral seed crystal, followed by ordering of two solid phases that nucleate heterogeneously on the seed and grow in a strongly coupled fashion. Crystallographic defects within the seed provide a template for spiral self‐organization. These observations demonstrate the ubiquity of defect‐mediated growth in multi‐phase materials and establish a pathway toward bottom‐up synthesis of chiral materials with an inter‐phase spacing comparable to the wavelength of infrared light. Given that liquids often possess polytetrahedral short‐range order, our results are applicable to many systems undergoing multi‐step crystallization.

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Section: Introductionmentioning

confidence: 99%

Multi‐Step Crystallization of Self‐Organized Spiral Eutectics

Moniri

Bale

Volkenandt

et al. 2020

Small

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“…This ripple effect is due to a complex interplay of solution flow, solute diffusion, the solvent evaporation, and the crystal growth. 48 , 49 …”

Section: Resultsmentioning

confidence: 99%

Shaping Perovskites: In Situ Crystallization Mechanism of Rapid Thermally Annealed, Prepatterned Perovskite Films

Günzler

Bermúdez‐Ureña

Muscarella

et al. 2021

ACS Appl. Mater. Interfaces

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Understanding and controlling the crystallization of organic–inorganic perovskite materials is important for their function in optoelectronic applications. This control is particularly delicate in scalable single-step thermal annealing methods. In this work, the crystallization mechanisms of flash infrared-annealed perovskite films, grown on substrates with lithographically patterned Au nucleation seeds, are investigated. The patterning enables the in situ observation to study the crystallization kinetics and the precise control of the perovskite nucleation and domain growth, while retaining the characteristic polycrystalline micromorphology with larger crystallites at the boundaries of the crystal domains, as shown by electron backscattering diffraction. Time-resolved photoluminescence measurements reveal longer charge carrier lifetimes in regions with large crystallites on the domain boundaries, relative to the domain interior. By increasing the nucleation site density, the proportion of larger crystallites is increased. This study shows that the combination of rapid thermal annealing with nucleation control is a promising approach to improve perovskite crystallinity and thereby ultimately the performance of optoelectronic devices.

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“…[43,44] Moreover, Figure 4c,d shows the 2D fast Fourier transform (2D-FFT) of the corresponding AFM images depicting the symmetry of the respective surface morphologies. [45,46] The EQE spectra (Figure 5a) are similar for all the OPD devices with different thicknesses of the active layer. Meanwhile, the EQE increases according to the active layer thickness irrespective of the wavelengths, suggesting higher optical absorption and charge generation in the thicker bulk heterojunction.…”

Section: Introductionmentioning

confidence: 87%

Vacuum‐Processed Small Molecule Organic Photodetectors with Low Dark Current Density and Strong Response to Near‐Infrared Wavelength

Lee

Estrada

et al. 2020

Advanced Optical Materials

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A near‐infrared photodetector with optimized performance is reported using varied thickness (20, 40, 60, and 80 nm) of the active layer comprising chloroaluminium phthalocyanine (ClAlPc) and fullerene (C70) at the ratio of 1:3, and TAPC:10% MoO3 and BPhen as electron and hole blocking layers, respectively. The experimental results reveal that the photodetector with 80 nm thick active layer provides the best performance at the wavelength of 730 nm achieving a very low dark current density of 1.15 × 10−9 A cm−2 and an external quantum efficiency of 74.6% with a responsivity of 0.439 A W−1 at −2 V bias. Additionally, the device exhibits a dramatic high detectivity of 4.14 × 1013 cm Hz1/2 W−1 at 0 V bias. The device exhibits not only a large linear response over a wide optical power range (LDR of 173.0 dB), but also a broad frequency response (778.7 kHz) and rise/fall time of 2.13/0.77 µs (based on trigger pulses at a frequency of 10 kHz) at the applied bias of −2 V. Based on the impedance spectroscopic study and the conventional characterization of electro‐optical properties, the results demonstrate the superiority of this device over other small molecule‐based near‐infrared photodetectors.

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Formation of aligned periodic patterns during the crystallization of organic semiconductor thin films

Cited by 48 publications

References 48 publications

Multi‐Step Crystallization of Self‐Organized Spiral Eutectics

Multi‐Step Crystallization of Self‐Organized Spiral Eutectics

Shaping Perovskites: In Situ Crystallization Mechanism of Rapid Thermally Annealed, Prepatterned Perovskite Films

Vacuum‐Processed Small Molecule Organic Photodetectors with Low Dark Current Density and Strong Response to Near‐Infrared Wavelength

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