Theoretical Study of the Effect of π-Bridge on Optical and Electronic Properties of Carbazole-Based Sensitizers for DSSCs.

Tomás Delgado-Montiel,Jesús Baldenebro-López,Rody Soto-Rojo,Daniel Glossman-Mitnik

doi:10.3390/molecules25163670

Abstract

Eight novel metal-free organic sensitizers were proposed for dye-sensitized solar cells (DSSCs), theoretically calculated and studied via density functional theory with D-π-A structure. These proposals were formed to study the effect of novel π-bridges, using carbazole as the donor group and cyanoacrylic acid as the anchorage group. Through the M06/6-31G(d) level of theory, ground state geometry optimization, vibrational frequencies, the highest occupied molecular orbital, the lowest unoccupied molecular orbital, and their energy levels were calculated. Further, chemical reactivity parameters were obtained and analyzed, such as chemical hardness (η), electrophilicity index (ω), electroaccepting power (ω+) and electrodonating power (ω-). Free energy of electron injection (ΔGinj) and light-harvesting efficiency (LHE) also were calculated and discussed. On the other hand, absorption wavelengths, oscillator strengths, and electron transitions were calculated through time-dependent density functional theory with the M06-2X/6-31G(d) level of theory. In conclusion, the inclusion of thiophene groups and the Si heteroatom in the π-bridge improved charge transfer, chemical stability, and other optoelectronic properties of carbazole-based dyes.

Highlights

Introduction66% of the world’s production depends on fossil fuel supply [1,2]
Modernity depends to a large extent on the production of electric power
We investigate a series of D-π-A organic dyes to study the effect of the π-bridge and its importance in the metal-free organic sensitizer, maintaining donor and acceptor units as carbazole and cyanoacrylic acid, respectively

Summary

Introduction

66% of the world’s production depends on fossil fuel supply [1,2]. For this and other environmental reasons, comes the need to make clean energy from renewable energy [3]. Dye-sensitized solar cells (DSSCs) are a novel proposal to create clean and environmentally friendly energy [4]. In their beginnings, DSSCs used ruthenium II-based sensitizers and later, metal-free organic sensitizers were utilized, making. These devices consist mainly of four components for their operation:

Objectives

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Conclusion