Manipulate organic crystal morphology and charge transport

This article reviews the synergistic effects of engineering binary solvents on the crystallization, morphology and charge transport of organic semiconductors.

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Binary solvent engineering for small-molecular organic semiconductor crystallization

Crystalline and liquid-crystalline conjugated small molecules represent a promising family of semiconductor materials for organic electronics applications. The control of the morphology and optoelectronic properties of small molecules allows tuning their charge transport characteristics and hence, improving the performance of electronic devices. Here, we designed four pentamers based on alternating thiophene and benzothiadiazole moieties and investigated the effect of their structure on the optoelectronic properties, ordering and charge transport characteristics. It is shown that thermal annealing of conjugated pentamers leads to remarkable changes in the microstructure and domain texture of thin films. As a result, an increase in hole mobility for compound M4 by one order of magnitude was achieved. These findings provide a valuable insight into the structure-property relationships for designed small molecules featuring them as promising semiconductor materials for further developing high-performance organic electronics.

Tailoring the charge transport characteristics in ordered small-molecule organic semiconductors by side-chain engineering and fluorine substitution.

Polymer semiconductors (PSCs) are essential active materials in mechanically stretchable electronic devices. However, many exhibit low fracture strain due to their rigid chain conformation and the presence of large crystalline domains. Here, a PSC/elastomer blend, poly[((2,6-bis(thiophen-2-yl)-3,7-bis(9-octylnonadecyl)thieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene)-5,5′-diyl)(2,5-bis(8-octyloctadecyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione)-5,5′-diyl]] (P2TDPP2TFT4) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) are systematically investigated. Specifically, the effects of molecular weight of both SEBS and P2TDPP2TFT4 on the resulting blend morphology, mechanical, and electrical properties are explored. In addition to commonly used techniques, atomic force microscopy-based nanomechanical images are used to provide additional insights into the blend film morphology. Opposing trends in SEBS-induced aggregation are observed for the different P2TDPP2TFT4 molecular weights upon increasing the SEBS molecular weight from 87 to 276 kDa. Furthermore, these trends are seen in device performance trends for both molecular weights of P2TDPP2TFT4. SEBS molecular weight also has a substantial influence on the mesoscale phase separation. Strain at fracture increases dramatically upon blending, reaching a maximum value of 640% ± 20% in the blended films measured with film-on-water method. These results highlight the importance of molecular weight for electronic devices. In addition, this study provides valuable insights into appropriate polymer selections for stretchable semiconducting thin films that simultaneously possess excellent mechanical and electrical properties. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aelm.202201055

Effect of Molecular Weight on the Morphology of a Polymer Semiconductor–Thermoplastic Elastomer Blend

Electronic structure of NdNiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si27.svg" display="inline" id="d1e451"><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> superconductor from ab initio density-functional-theory calculations

A binary system comprising both an organic semiconductor and a polymer additive has attracted extensive research interests due to great potential for high-performance, solution-proccessable electronic devices on flexible substrates. The...

/pdf/tailoring-molecular-weight-of-polymer-additives-for-organic-bc71812y.pdf

Tailoring Molecular Weight of Polymer Additives for Organic Semiconductors

Poly(α-methyl styrene) polymer additive for organic thin film transistors

Solvent Exchange in Controlling Semiconductor Morphology

We simulate and calculate numerically the electromagnetic field and energy flux in single crystal silicon thin film solar cell coated with silver nano-disk square array by using the finite-difference time-domain (FDTD) method. Because of the surface plasmon resonance (SPR) of silver nano array, the electromagnetic field is redistributed and enhanced in the solar cell. The simulation results show that the electromagnetic field distribution and corresponding energy flux component depend on the nano array and the structure of absorbed layer in solar cell. The wavelength of the incident light relative to the nano array determine the profile of the electric field around the nano array. The electromagnetic field distribution in thin film is determined by the internal structure of solar cell. For different incident wavelengths, the electromagnetic field distribution in solar cell will changes. The energy flux named as Poynting vector also changes with the incident wavelength. To investigate the absorption of the solar cell, the normalized absorbed power at different wavelengths is calculated. Based on the SPR effect, the solar cell exhibts absorption enhancement sharply at a certain wavelength.

Sheng Jie Bi

Papers

Manipulate organic crystal morphology and charge transport

Tailoring Molecular Weight of Polymer Additives for Organic Semiconductors

Poly(α-methyl styrene) polymer additive for organic thin film transistors

Solvent Exchange in Controlling Semiconductor Morphology

Distribution of Electromagnetic Field and Energy Flux in the Thin Film Solar Cell with Silver Nano-Disk Array