7-Alkoxy-appended coumarin derivatives: synthesis, photo-physical properties, aggregation behaviours and current-voltage (I-V) characteristic studies on thin films.

Abhijit Rudra Paul,Swapan Majumdar,Sudip Suklabaidya,Syed Arshad Hussain,Bapi Dey

doi:10.1039/d1ra00762a

Abstract

In this study, we designed and synthesised a series of coumarin derivatives appended with a long alkoxy chain on the seventh position of the coumarin-3-carboxylate/carboxylic acid core to make thin film materials. Synthesised compounds were characterized by their UV and fluorescence spectra in solutions as well as their films prepared by both LB and spin-coated methods. The surface morphology and electrical behaviour of thin films were judged by AFM, SEM and I–V characteristic mapping respectively. Isotherm, UV-Vis absorption and fluorescence spectroscopic investigations revealed the formation of aggregates on thin films. The result of SEM and AFM images provides the information about the length and height of aggregates on the thin films of coumarin derivatives. From I–V characteristics, it was found that at room temperature, the spin-coated films of coumarin derivatives containing an ester functional group exhibited a threshold switching behaviour, whereas derivatives containing the carboxylic acid functional group showed both threshold and bipolar switching behaviours. We also noticed that the I–V characteristic features of synthesized materials depended on the length of the alkyl chain of individual series.

Highlights

Electronic and optoelectronic devices are used in various applications ranging from simple household appliances to communications, computing, and medical instruments, and they are considered as basic building blocks for modern civilization
We noticed that the instrument. The current–voltage (I–V) characteristic features of synthesized materials depended on the length of the alkyl chain of individual series
Synthesis A series of coumarin derivatives (2a–e and 3a–e) containing a long alkoxy chain and an electron-withdrawing group at position 3 were prepared for our study by a straightforward twostep process from ethyl 7-hydroxy-coumarin-3-carboxylate (1), which was synthesized from 2,4-dihydroxybenzaldehyde and diethylmalonate by a known protocol.[35]

Summary

Introduction

Electronic and optoelectronic devices are used in various applications ranging from simple household appliances to communications, computing, and medical instruments, and they are considered as basic building blocks for modern civilization. From I–V characteristics, it was found that at room temperature, the spin-coated films of coumarin derivatives containing an ester functional group exhibited a threshold switching behaviour, whereas derivatives containing the carboxylic acid functional group showed both threshold and bipolar switching behaviours.

Results

Conclusion