Enhancement of the Exciton Coherence Size in Organic Semiconductor by Alkyl Chain Substitution

Photophysical properties of molecular aggregates are largely determined by exciton coherence size: a spatial extension of exciton delocalization. Increase in exciton coherence size can lead to fast energy transport as well as efficient charge separation. Here, we demonstrate that introducing alkyl chains to organic molecules can enhance the exciton coherence size significantly. Focusing on the thin films of excellent hole transport materials, dinaphtho­[2,3-<i>b</i>:2,3-<i>f</i>]­thieno­[3,2-<i>b</i>]­thiophene (DNTT) and its alkyl-substituted derivative, we analyze the steady-state and picosecond time-resolved photoluminescence spectra of the films to estimate exciton coherence sizes. The alkyl substitution enhances the coherence size by a factor of 2–3, indicating that a long-range ordering in the molecular aggregates is achieved with the additional van der Waals interaction between saturated alkyl chains. The coherence sizes of both the films decrease with increasing temperature owing to thermal populations within the vibronic exciton manifolds

Fine-Tuning the Performance of Ultraflexible Organic Complementary Circuits on a Single Substrate via a Nanoscale Interfacial Photochemical Reaction

Flexible electronics has paved the way toward the development of next-generation wearable and implantable healthcare devices, including multimodal sensors. Integrating flexible circuits with transducers on a single substrate is desirable for processing vital signals. However, the trade-off between low power consumption and high operating speed is a major bottleneck. Organic thin-film transistors (OTFTs) are suitable for developing flexible circuits owing to their intrinsic flexibility and compatibility with the printing process. We used a photoreactive insulating polymer poly((±)endo,exo-bicyclo[2.2.1]hept-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE) to modulate the power consumption and operating speed of ultraflexible organic circuits fabricated on a single substrate. The turn-on voltage (Von) of the p- and n-type OTFTs was controlled through a nanoscale interfacial photochemical reaction. The time-of-flight secondary ion mass spectrometry revealed the preferential occurrence of the PNDPE photochemical reaction in the vicinity of the semiconductor–dielectric interface. The power consumption and operating speed of the ultraflexible complementary inverters were tuned by a factor of 6 and 4, respectively. The minimum static power consumption was 30 ± 9 pW at transient and 4 ± 1 pW at standby. Furthermore, within the tuning range of the operating speed and at a supply voltage above 2.5 V, the minimum stage delay time was of the order of hundreds of microseconds. We demonstrated electromyogram measurements to emphasize the advantage of the nanoscale interfacial photochemical reaction. Our study suggests that a nanoscale interfacial photochemical reaction can be employed to develop imperceptible and wearable multimodal sensors with organic signal processing circuits that exhibit low power consumption

موسى بن محمد قاضي زاده الرومي. أشكال التأسيس

Numérisation effectuée à partir d'un document de substitution.Commentaire des Aškāl al-ta'sīs de Muḥammad ibn Ašraf al-Samarqandī. Titre au f. 2. Inc. (f. 2v) : الحمد لله الذي خلق كل شيء بقدر وقدر له ما يليق من أشكال وصور... وبعد فإن الهندسة مع متانة مسائلها Exp. (f. 50v) : وهذه الأشكال الخمسة الأخيرة من ثانية كتاب الأصول لأقليدس وليكن هذا آخر الكلام وقد تم الكتاب Copie achevée par ʿAbd al-Qādir ibn Muṣṭafā al-Ḥallāq le 12 šawwāl 1176 h. / 26 avril 1763.Cachet et marque du commanditaire de la copie : Muḥammad ʿĀrif, mudarris à Dār al-Sulṭana, Marque de possession de Muḥammad ibn Ḥusayn (?) (f. 1). Indication de prix : 15 piastres (f. 1). Marque à l'encre violette datée du 3 šaʿbān 1361 h. / 16 août 1942, au nom de Muḥammad al-Amīn ibn Muḥammad ʿAbd Allāh (f. 1v

Boron-Stabilized Planar Neutral π‑Radicals with Well-Balanced Ambipolar Charge-Transport Properties

Organic neutral π-monoradicals are promising semiconductors with balanced ambipolar carrier-transport abilities, which arise from virtually identical spatial distribution of their singly occupied and unoccupied molecular orbitals, SOMO­(α) and SOMO­(β), respectively. Herein, we disclose a boron-stabilized triphenylmethyl radical that shows outstanding thermal stability and resistance toward atmospheric conditions due to the substantial spin delocalization. The radical is used to fabricate organic Mott-insulator transistors that operate at room temperature, wherein the radical exhibits well-balanced ambipolar carrier transport properties

Boron-Stabilized Planar Neutral π‑Radicals with Well-Balanced Ambipolar Charge-Transport Properties

Organic neutral π-monoradicals are promising semiconductors with balanced ambipolar carrier-transport abilities, which arise from virtually identical spatial distribution of their singly occupied and unoccupied molecular orbitals, SOMO­(α) and SOMO­(β), respectively. Herein, we disclose a boron-stabilized triphenylmethyl radical that shows outstanding thermal stability and resistance toward atmospheric conditions due to the substantial spin delocalization. The radical is used to fabricate organic Mott-insulator transistors that operate at room temperature, wherein the radical exhibits well-balanced ambipolar carrier transport properties