Synthesis and photovoltaic performance of novel ullazine-based organic dyes for dye-sensitized solar cells

Abstract

Two new ullazine-based organic dyes have been synthesized for applications in nanocrystalline TiO 2 -based dye-sensitized solar cells (DSSCs). Overall conversion efficiencies up to 3.63% were obtained for DSSCs based on these dyes. The dye with a tert-butyl antenna exhibited a higher and redshifted absorption pattern resulting in increased light-harvesting property. Compared to the unsubstituted dye, the photocurrent density, open-circuit photovoltage and overall power conversion efficiency (PCE) of solar cells based on the tert-butyl substituted dye are improved. The decreased PCE of the solar cell based on unsubstituted dye results mainly from the increased recombination rate and decreased electron lifetime, as evidenced from impedance and photovoltage decay measurements. Density functional theory (DFT) and time-dependent DFT calculations were performed to predict the geometries, electronic structure, and the optical and electrochemical properties of the dyes.

π-Expanded azaullazines: synthesis of quinolino-azaullazines by Povarov reaction and cycloisomerisation

“…Indolizino[6,5,4,3- ija ]quinolines (ullazines), first synthesized and studied by Balli et al in 1983, 1 are of considerable current interest in the field of materials science, due to their application as organic light emitting diodes (OLEDs), organic field-effect transistors (OFETs) or dye-sensitized solar cells (DSSC). 2,3 Due to the electronic influence of the pyrrole moiety, ullazines represent electron-rich molecules that exhibit strong intramolecular charge transfer (ICT). 2 Several synthetic methods have been developed in recent decades to further modify the properties of ullazines.…”

Maximum Power Point Tracking Control Method of Photovoltaic Cell under Shadow Influence

“…The transition of solar generation into large-scale commercial electricity and its integration with the electrical industry is a critical direction. [5] Y. Meng There is an interconnected relationship between battery (Group) and solar cell array, so the following three situations are very likely to occur. Firstly, when the solar cell array has not operated at the maximum power point, its output voltage and current are very unstable, and the system output power cannot achieve the maximum value, which consumes local energy and reduces the overall output benefit of the device [6].…”

Divergent Synthesis of 5,7-Diazaullazines Derivatives through a Combination of Cycloisomerization with Povarov or Alkyne–Carbonyl Metathesis

“…A comparison of symmetrical (8) and unsymmetrical (6a) substituted diazaullazines, as well as π-expanded aza- (7) and diazaullazines (5a), reveal the impact of nitrogen doping, π-expansion, and the substitution pattern on the properties of these ullazine derivatives (Table 3) [29,30].…”

“…Ullazine contains 16-π-electrons, is isoelectronic to pyrene, and is a representative of polycyclic heteroaromatic hydrocarbons (PAHs) [1]. It has been known since its first synthesis in 1983 [2], but has gained much interest for applications in organic electronics during the last decade [1, [3][4][5][6][7] since Grätzel et al disclosed its promising application in dye-sensitized solar cells in 2013 [1]. The aromatic 14-π-electron resonance structure is a key factor, consisting of an electron-accepting iminium center surrounded by an electron-donating annulene.…”