A new class of organic sensitizers with fused planar triphenylamine for nanocrystalline dye sensitized solar cells

Recent Advances in Selenophene-Based Materials for Organic Solar Cells

Due to the low cost, light weight, semitransparency, good flexibility, and large manufacturing area of organic solar cells (OSCs), OSCs have the opportunity to become the next generation of solar cells in some specific applications. So far, the efficiency of the OSC device has been improved by more than 20%. The optical band gap between the lowest unoccupied molecular orbital (LUMO) level and the highest occupied molecular orbital (HOMO) level is an important factor affecting the performance of the device. Selenophene, a derivative of aromatic pentacyclic thiophene, is easy to polarize, its LUMO energy level is very low, and hence the optical band gap can be reduced. In addition, the selenium atoms in selenophene and other oxygen atoms or sulfur atoms can form an intermolecular interaction, so as to improve the stacking order of the active layer blend film and improve the carrier transport efficiency. This paper introduces the organic solar active layer materials containing selenium benzene in recent years, which can be simply divided into donor materials and acceptor materials. Replacing sulfur atoms with selenium atoms in these materials can effectively reduce the corresponding optical band gap of materials, improve the mutual solubility of donor recipient materials, and ultimately improve the device efficiency. Therefore, the sulfur in thiophene can be completely replaced by selenium or oxygen of the same family, which can be used in the active layer materials of organic solar cells. This article mainly describes the application of selenium instead of sulfur in OSCs.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

N-Heterotriangulene chromophores with 4-pyridyl anchors for dye-sensitized solar cells

A series of N-heterotriangulenes decorated with 4-pyridyl anchors were synthesized and their performance in n-type TiO₂- and ZnO-based dye-sensitized solar cells investigated.

The electronic structure engineering of organic dye sensitizers for solar cells: The case of JK derivatives

The design and development of novel dye sensitizers are effective method to improve the performance of dye-sensitized solar cells (DSSCs) because dye sensitizers have significant influence on photo-to-current conversion efficiency. In the procedure of dye sensitizer design, it is very important to understand how to tune their electronic structures and related properties through the substitution of electronic donors, acceptors, and conjugated bridges in dye sensitizers. Here, the electronic structures and excited-state properties of organic JK dye sensitizers are calculated by using density functional theory (DFT) and time dependent DFT methods. Based upon the calculated results, we investigated the role of different electronic donors, acceptors, and π-conjugated bridges in the modification of electronic structures, absorption properties, as well as the free energy variations for electron injection and dye regeneration. In terms of the analysis of transition configurations and molecular orbitals, the effective chromophores which are favorable for electron injection in DSSCs are addressed. Meanwhile, considering the absorption spectra and free energy variation, the promising electronic donors, π-conjugated bridges, and acceptors are presented to design dye sensitizers.

Photophysical and electrochemical properties, and molecular structures of organic dyes for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO(2), ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident-solar-light-to-electricity conversion efficiency and low cost of production. To develop high-performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light-harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch-making molecular design of organic dyes for high photovoltaic performance and long-term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far.