Metal Complex Dye for Long Wavelength Photoelectric Conversion
Solution Overview
Problem
Dye-sensitized solar cells face challenges in improving photoelectric conversion efficiency, particularly in the long wavelength side beyond 700 nm, where the efficiency is low, and there is a need for enhanced heat resistance and durability.
Innovation Solution
A photoelectric conversion element with a laminate structure incorporating a metal complex dye represented by a specific formula, featuring a nitrogen-containing tridentate ligand and bidentate ligand coordination, which enhances the Incident Photon-to-Current Efficiency (IPCE) even in the long wavelength region, achieved through the expansion of the conjugated system and stabilization of the one-electron oxidation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dye amount is reduced to improve efficiency, then photoelectric conversion efficiency improves, but heat resistance and durability may be compromised
Solution Approach 1:
The patent selects specific parameter combinations in the dye structure, particularly using stable metal centers (Ru, Os, Ir) with appropriate ligand fields that provide both high photoelectric conversion efficiency and thermal stability. The tridentate L1 ligand with acidic group and bidentate L2 ligand create a stable coordination environment that maintains durability while achieving high efficiency.
Solution Approach 2:
The composite dye structure with multiple ligands coordinated to a stable metal center creates a molecular architecture that inherently provides both high efficiency and durability. The synergistic interaction between L1 (with acidic group for stability), L2 (for light absorption), and Z1 (monodentate ligand) creates a dye that maintains reliability even at reduced concentrations.
2Use of energy by moving object
If IPCE is improved in long wavelength region, then light utilization efficiency increases, but device complexity increases
Solution Approach 1:
The patent achieves improved long wavelength IPCE by systematically varying parameters in the dye structure, such as introducing electron-donating or electron-withdrawing substituents (R1-R12) on the ligands, which tune the HOMO-LUMO energy gap to extend absorption into the long wavelength region. This parameter optimization improves light utilization without requiring complex device architectures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly improves photoelectric conversion efficiency and durability, achieving high IPCE and efficient light utilization in the long wavelength side, exceeding 700 nm, while maintaining high heat resistance and durability.
Implementation Method 1
photoelectric conversion efficiency, Incident Photon-to-Current Efficiency (IPCE)
Implementation Method 2
charge transfer layer, photoconductor layer having a layer of dye-adsorbed semiconductor fine particles
Data Source
AI summary
A photoelectric conversion element having a laminate structure including, provided on an electrically conductive support, a photoconductor layer having a layer of dye-adsorbed semiconductor fine particles, a charge transfer layer, and a counter electrode, wherein the dye is a metal complex dye represented by the following formula (1):M1L1L2Z1 (1)wherein, in formula (1), M1 represents a metal atom; Z1 represents a monodentate ligand; L1 represents a specific tridentate ligand; and L2 represents a specific bidentate ligand.