Dye-Sensitized Solar Cells Based on Cu(I) Complexes Containing Catechol Anchor Groups That Operate with Aqueous...

Area of Science:

• Materials Science
• Photovoltaics
• Coordination Chemistry

Background:

• Developing efficient and stable light-harvesting materials is crucial for advancing solar cell technology.
• Copper-(I) complexes offer potential as cost-effective alternatives to noble metal sensitizers in dye-sensitized solar cells (DSSCs).
• Phenanthroline-based ligands are widely explored for their ability to form stable metal complexes with tunable electronic properties.

Purpose of the Study:

• To design and synthesize novel phenanthroline-based ligands and their corresponding copper-(I) complexes.
• To investigate the photophysical, electrochemical, and photovoltaic properties of these new materials.
• To evaluate the performance of the synthesized copper-(I) complexes as sensitizers in n-type dye-sensitized solar cells (DSSCs).

Main Methods:

• Synthesis of catechol-functionalized phenanthroline ligands (L1, L1') and copper-(I) complexes (C1, C1', C2, C2').
• Characterization using steady-state and time-resolved spectroscopy, cyclic voltammetry, and density functional theory (DFT) calculations.
• Fabrication and testing of n-type DSSCs using the synthesized complexes, with performance evaluated by photoconversion efficiency (PCE) and incident photon-to-current efficiency (IPCE).

Main Results:

• A heteroleptic copper-(I) complex (C2) achieved a photoconversion efficiency (PCE) of 1.88% in n-type DSSCs, a 35-fold improvement over previous diimine-diphosphine copper-(I) based DSSCs.
• Efficient photoinduced charge injection and interfacial electron transfer were confirmed by IPCE and electrochemical impedance spectroscopy.
• The catechol anchors facilitated the use of aqueous electrolytes, leading to stable DSSC performance for over 10 days.

Conclusions:

• Novel phenanthroline-based copper-(I) complexes show significant promise for efficient and stable dye-sensitized solar cells.
• The dual chromophore system, involving catechol-TiO2 interaction and copper-(I) complex antenna, enhances solar cell performance.
• The development of stable DSSCs with aqueous electrolytes using these materials represents a significant advancement in photovoltaic research.