Rational Design and Synthesis of Robust Thiocyanate-Free Metal-Organic Dyes for High-Performance Dye-Sensitized Solar Cells

  • WONG, Wai Yeung (PI)

Project: Research project

Project Details

Description

The area of sustainable energy is a hot topic in the 21st century. As the most abundant, renewable and clean energy source on the Earth, solar energy is one of the best candidates for solving the worldwide energy crisis. Owing to their versatility, low cost and ease of fabrication of foldable and flexible large-area solar-energy conversion devices, dye-sensitized solar cells (DSSCs) have received surging academic and industrial attention as potential candidates for the future photovoltaic market. Since the seminal breakthrough by Grätzel and co-workers, ruthenium(II)-based photosensitizers become the benchmark for DSSCs. However, the thiocyanate ligands incorporated in most of these Ru(II) photosensitizers tend to render the sensitizers unstable under excessive thermal stress and/or light soaking. To commercialize DSSCs, both long term stability and efficiency should be further improved. Herein, we propose to design and develop a new suite of thiocyanate-free Ru(II) photosensitizers together with some non-classical organometallic dye molecules of Ir(III) and Pt(II) that would offer a good avenue towards fabricating high-efficiency and durable DSSCs. These metal-organic dyes will be studied in the appropriate nanostructured (nanocrystalline and nanowire) DSSC settings with both liquid-electrolyte and solid-state cells. With our strengths in synthetic chemistry, optimization of the dye component of the solar cell will be garnered through systematic variation of the ligands, metal, and other substituent groups in these metal complexes. The present work will fill in an innovative area of energy science and also provide a new impetus to the production of some robust metal-based photosensitizers with higher molar extinction coefficients and more red-shifted absorption bands relative to the benchmark compounds. While the development of DSSC dyes that can harvest solar radiation over a broad spectral range has yet proven difficult, molecular cosensitization approach using multiple dyes with complementary absorption properties is an emerging method to obtain panchromatic absorption, and should lead to higher energy-conversion efficiencies. Furthermore, high-efficiency DSSCs typically operate as dye-sensitized photoanodes (n-DSSCs), where photocurrents result from dye-sensitized electron injection into n-type semiconductors. Dye-sensitized photocathodes (p-DSSCs) perform the function in an inverse mode, where excitation of dye is followed by rapid electron transfer from a p-type semiconductor to the dye. It is therefore desirable to develop highly efficient p-n tandem DSSCs based on some of our good n-type metal-organic dyes. This new combination of both photoactive electrodes in a tandem cell will significantly improve the overall device performance.
StatusFinished
Effective start/end date1/01/1231/12/14

UN Sustainable Development Goals

In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):

  • SDG 7 - Affordable and Clean Energy

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