Novel D-A-π-A type benzocarbazole sensitizers for dye sensitized solar cells

Control and regulation of the performance of fullerene-based dye-sensitized solar cells with a D-D-A structure by external electric fields

We investigated the modulating effect of an electric field (F_ext) on the photovoltaic properties of triphenylamine-based sensitizers with a D-D-A structure and compared the photovoltaic parameters at different electric field intensities. The results show that F_ext can effectively adjust the photoelectric properties of the molecule. From the change of the parameters that measures the degree of electron delocalization, it can be seen that the F_ext can effectively strengthen the electronic communication and promote the charge transfer process within the molecule. And the dye molecule under a strong F_ext has a narrower energy gap, more favorable injection, regeneration driving force and a larger conduction band energy level shift, which ensures that the dye molecule can exhibit larger V_oc and J_sc under a strong F_ext. The results of calculations on the photovoltaic parameters of dye molecules show that dye molecules can exhibit better photovoltaic performance under the action of F_ext, which provides beneficial predictions and prospects for the development of highly efficient DSSCs.

Synthesis of innovative triphenylamine-functionalized organic photosensitizers outperformed the benchmark dye N719 for high-efficiency dye-sensitized solar cells

Herein, we present a thorough photovoltaic investigation of four triphenylamine organic sensitizers with D-π-A configurations and compare their photovoltaic performances to the conventional ruthenium-based sensitizer N719. SFA-5-8 are synthesized and utilized as sensitizers for dye-sensitized solar cell (DSSC) applications. The effects of the donor unit (triphenylamine), π-conjugation bridge (thiophene ring), and various acceptors (phenylacetonitrile and 2-cyanoacetamide derivatives) were investigated. Moreover, this was asserted by profound calculations of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, the molecular electrostatic potential (MEP), and natural bond orbital (NBO) that had been studied for the TPA-sensitizers. Theoretical density functional theory (DFT) was performed to study the distribution of electron density between donor and acceptor moieties. The sensitization by the absorption of sensitizers SFA-5-8 leads to an obvious enhancement in the visible light absorption (300-750 nm) as well as a higher photovoltaic efficiency in the range of (5.53-7.56%). Under optimized conditions, SFA-7 showed outstanding sensitization of nanocrystalline TiO2, resulting in enhancing the visible light absorption and upgrading the power conversion efficiency (PCE) to approximately 7.56% over that reported for the N719 (7.29%). Remarkably, SFA-7 outperformed N719 by 4% in the total conversion efficiency. Significantly, the superior performance of SFA-7 could be mainly ascribed to the higher short-circuit photocurrents (Jsc) in parallel with larger open-circuit voltages (Voc) and more importantly, the presence of different anchoring moieties that could enhance the ability to fill the gaps on the surface of the TiO2 semiconductor. That could be largely reflected in the overall enhancement in the device efficiency. Moreover, the theoretical electronic and photovoltaic properties of all studied sensitizers have been compared with experimental results. All the 2-cyanoacrylamide derivative sensitizers demonstrated robust photovoltaic performance.

Novel photosensitizer for dye-sensitized solar cell based on ionic liquid–doped blend polymer electrolyte

The existing energy situation demands not only the huge energy in a short time but also clean energy. In this regard, an integrated photo-supercapacitor device has been fabricated in which photoelectric conversion and energy storage are achieved simultaneously. A novel carbazole-based dye is synthesized and characterized for photosensitizer. The silver-doped titanium dioxide (Ag-TiO2) is synthesized, and it is used as photoanode material. Different concentrations of tetrabutylammonium iodide (TBAI)-doped polyvinyl alcohol–polyvinylpyrrolidone (PVA-PVP) blend polymer electrolytes are prepared, and their conductivity and dielectric properties were studied. Reduced graphene oxide (r-GO) is synthesized by a one-pot synthesis method and confirmed using Raman spectroscopy for counter electrode material in dye-sensitized solar cell (DSSC) and supercapacitor electrodes. The DSSC having 4% Ag-TiO2–based photoanode showed the highest efficiency of 1.06% (among r-GO counter electrodes) and 2.37% (among platinum counter electrodes). The supercapacitor before integration and after integration exhibits specific capacitance of 1.72 Fg−1 and 1.327 Fg−1, respectively.

Light Harvesting and Optical-Electronic Properties of Two Quercitin and Rutin Natural Dyes

The photovoltaic properties of two dyes (quercitin (Q) and rutin (R)) were experimentally investigated. The results showed that Q had excellent photoelectric properties with J s c of 5.480 mA·cm−2, V o c of 0.582 V, η of 2.151% larger than R with J s c of 1.826 mA·cm−2, V o c of 0.547 V, and η of 0.713%. For a better understanding of the photoelectric properties of two molecules and illustrating why the performances of Q is better than R from the micro-level, the UV-VIs spectrum, Fourier transforms infrared (FT-IR) spectrum, and cyclic voltage current characteristics were experimentally investigated. What is more, density functional theory (DFT) and time dependent density functional theory (TD-DFT) have been implemented in theoretical calculation. Based on the calculated results, frontier molecular orbitals (FMOs), charge differential density (CDD), infrared vibration, first hyperpolarizability, projected density orbital analysis (PDOS), electrostatic potential (ESP), and natural bond orbital (NBO) were analyzed. Hole/electron reorganization energies ( λ h / λ e ), light harvesting efficiency (LHE), fluorescent lifetime (τ), absorption peak, and the vertical dipole moment ( μ n o r m a l ) were calculated, and the shift of conduction band edge of a semiconductor (ΔECB) has been analyzed, which has a close relationship with J s c and V o c . The results demonstrated that, due to the higher LHE, τ, μ n o r m a l , and red-shifted absorption peak, Q has better photoelectric properties than R as a promising sensitizer.