Design and synthesis of the quinacridone-based donor polymers for application to organic solar cells

Unveiling next-generation organic photovoltaics: Quantum mechanical insights into non-fullerene donor-acceptor compounds

Organic photovoltaics (OPVs) have improved greatly in recent years in pursuit for efficient and sustainable energy conversion methods. Specifically, utilizing quantum chemistry approaches such as density functional theory (DFT), the electronic structures, energy levels, and charge transport characteristics of donor-π-acceptor (D-π-A) systems based on non-fullerene donor and acceptor molecules have been examined and synthesized. Non-fullerene acceptors offer several advantages over traditional fullerene-based materials, such as enhanced light absorption, modifiable energy levels, and reduced recombination losses. Quantum mechanical simulations are helpful in the design and development of these materials because they can accurately predict the energy level alignment, molecule interactions, and charge transport properties needed for the high-efficiency of OPVs. The research begins through the selection of electron-donating and electron-accepting non-fullerene polymeric molecules using the unique properties of non-fullerene derivatives and non-fullerene acceptors. The theory uses the B3LYP-D3 method with a 6-31+G (d,p) basis set. PY-IT is used as the reference molecule, and eight molecules PY-IT01-PY-IT08, has been created by changing the end caps of the acceptor units. The created compound has superior photovoltaic characteristics. Focus has been specifically given to the frontier molecular orbitals (FMOs), natural bond order (NBO) analysis, reorganization energies (RE), and absorption spectra in order to assess the viability of charge separation and efficient light absorption. Finally, the molecular electrostatic potential (MEP) analysis, transition density matrix (TDM) analysis, and improved open circuit voltage (Voc) all have been computed. The results of the findings provide new insight to design organic solar cells (OSCs) with improved photovoltaic and solar energy conversion capabilities, which has great potential for the future development of more dependable and efficient OSCs.

Rheological Properties of Polyethylene Color Masterbatches Containing Pigment RED 122 (2,9-Dimethylquinacridone) Modified by Silanes Using Pulverization Method

Polyethylene color masterbatches containing pigment RED 122, 2,9-dimethylquinacridone, ((2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione) modified by the pulverization method in ball mills were obtained. As pigment-modifying agents, isobutyltrimethoxysilane IBTMS and octyltrietoxysilane OTES were used. The viscoelastic properties of the prepared masterbatches were investigated by using an oscillation rotational rheometer. The impact of the 2 wt.% of coloring masterbatch on the rheological behavior of polyethylene during processing at 170 °C was analyzed. Storage shear modulus G', loss shear modulus G″, complex viscosity η* and loss factor tan δ were analyzed. Modification prevents the agglomeration of modified pigment particles in the masterbatch, leading to a significant increase in the storage shear modulus G', from 13.83 kPa (masterbatch containing pigment RED 122) to 58.74 kPa (pigment modified with 2 wt.% of IBTMS) and 49.67 kPa (pigment modified with 2 wt.% of OTES). The analysis of the continuous relaxation models showed that the modified pigment influenced the relaxation of melted polyethylene. The tendency of the silane-modified pigment to create its "own structure" in the polyethylene carrier via particle-particle interactions was estimated based on rotational tests at low and high shear rates. The larger area of viscosity loops was determined at 170 °C for the masterbatch containing 1 wt.% of OTES-modified pigment, 2574.44 Pas(1/s), as compared with the reference masterbatch, 464.88 Pas(1/s). The Carreau and Carreau-Yasuda viscosity models were applied to analyze the flow curve and the changes in viscosity as a function of the shear rate. After pigment modification, the zero shear viscosity µ0 of the mixtures of polyethylene/pigment masterbatch changed from 234.9 Pas (pigment RED 122) to 305.9 Pas (pigment modified with 1 wt.% of IBTMS). The influence of the modified pigments on the crystallization of polyethylene and its thermal stability was investigated. The temperatures of melting Tm were determined.