ABSTRACT
Because of the increasing scarcity of fossil fuels and the growing need for energy, it has become necessary to research new renewable energy resources. In this study, five new high-performance materials (TP-FA1F-TP - TP-FA5F-TP) of the D-π-A-π-D configuration based on triphenylamine (TPA) were theoretically investigated by applying DFT and TD-DFT methods for future application as heterojunction organic solar cells (BHJ). The influence of the modification of the acceptor (A) of the parent molecule TP-FTzF-TP on the structural, electronic, photovoltaic and optical properties of the TP-FA1F-TP - TP-FA5F-TP organic molecules was investigated in detail. TP-FA1F-TP - TP-FA5F-TP showed Egap in the interval of 1.44-2.01 eV with λabs in the range of 536-774 nm, open-circuit voltage (Voc) values varied between 0.3 and 0.56 V and power conversion efficiencies (PCE) ranging from (3-6) %. Our results also show that the donor molecules suggested in this research exhibit an improved performance compared to the recently synthesized TP-FTzF-TP, such as a lowest HOMO energy, a smaller Egap, and a greater absorption spectrum, and can lead to higher performance. Indeed, this theoretical research could lead to the future synthesis of better compounds as active substances used in BHJ.
Subject(s)
Amines , Electrons , Density Functional Theory , Electronics , Renewable EnergyABSTRACT
Global energy consumption has increased due to population growth and economic development. Solar energy is one of the most important renewable energy sources for human consumption. In this research, four novel organic dyes (D2-D5) of the D-A-π-A structure based on triphenylamine (TPA) were studied theoretically using DFT and TD-DFT techniques for future usage as dye-sensitized solar cells (DSSCs). The effects of modifying the π-spacer of the reference molecule D1 on the structural, electronic, photovoltaic, and optical characteristics of the D2-D5 dyes were studied in detail. D2-D5 exhibited band gaps (E gap) in the range from 1.89 to 2.10 eV with λ abs in the range of 508 to 563 nm. The results obtained show that modifying the π-spacer of the dye D1 increased its hole injection and reinforced the intramolecular charge-transfer (ICT) impact, which resulted in a red-shifted ICT absorption with a greater molar extinction coefficient. The theoretically calculated open-circuit voltage (V oc) values ranged from 0.69 to 1.06 eV, while the light-harvesting efficiency (LHE) values varied from 0.95 to 0.99. Indeed, this theoretical research could guide chemists to synthesize effective dyes for DSSCs.
ABSTRACT
The investigation of dye-sensitized solar cells (DSSCs) based on different donor groups linked with cyanoacrylic acid electron acceptor by Selenophene as π-bridged (D-π-A) was performed based on density functional theory (DFT) time-dependent DFT (TDDFT). Different functional were tested W97XD, PBEPBE, CAM-B3LYP, and B3PW91, and compared with experimental results of the reference D1. The theoretical results with CAM-B3LYP functional at 6-311G (d,p) basis sets were capable of predicting the absorption maximum that has been reported experimentally. Calculations were made to establish the conformational orientation of the cyanoacrylic acid group and evaluate the effect of changing donor units' on the electronic properties of the ground state. Structural and electronic properties, along with the photovoltaic properties, were investigated. The LUMO and HOMO energy levels of these dyes can positively affect the process of electron injection and dye regeneration. Light-harvesting efficiency (LHE), injection driving force (ΔGinject), and total reorganization energy (total) were also discussed. To further support the previous proprieties, electronic excited state energies were obtained by TDDFT// CAM-B3LYP/6-311G(d,p) calculations. The calculated results of these dyes reveal that D8 dye possessing triphenylamine donor unit has the best electronic, optical properties, and photovoltaic parameters.
