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Hole Transport Materials by Direct C‐H Arylation for Organic Solar Cells: Effect of Structure and Conjugation on Electrical, Optical and Computational Properties
Author(s) -
Naqvi Sheerin,
Chaudhary Neeraj,
Singhal Sanchita,
Yadav Preeti,
Patra Asit
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202004241
Subject(s) - conjugated system , organic solar cell , electronegativity , molecule , band gap , materials science , heteroatom , energy conversion efficiency , small molecule , absorption (acoustics) , density functional theory , solar cell , absorption spectroscopy , electronic structure , chemistry , computational chemistry , organic chemistry , polymer , optoelectronics , optics , ring (chemistry) , biochemistry , physics , composite material
Significant efforts have been devoted to the synthesis of conjugated molecules due to their interesting properties for organic electronic applications, it is surprising that very few studies have been reported on the development of small molecules for hole transport material (HTM) in organic solar cells through direct C−H arylation. In this work, we have studied the reaction conditions used for the facile synthesis of a series of π conjugated small molecules through direct C−H arylation. The reaction condition was optimized by using different solvents, bases and ligands to achieve the maximum possible yield. Ten phenyl(s)‐flanked conjugated small molecules were prepared using the optimized reaction condition and were characterized. Density functional theory was studied on these molecules to understand the structure‐property relationship and predicting the reliable geometry, electronic structure and properties of conjugated systems. Electrical and optical properties were measured by cyclic voltammetry and UV‐vis absorption spectroscopy. Finally, the organic solar cells were fabricated by solution‐processable deposition of these HTM with device geometry of ITO/HTM/PCDTBT:PC 70 BM/Al and achieved a power conversion efficiency of 2.40 % under ambient conditions. This method has the advantages of using different aromaticity of heterocyclic rings combined with conjugation length and electronegativity of heteroatom(s) to allow fine‐tuning of HOMO level and band gap engineering.