第一原理理論研究具有全色域吸收之染料敏化劑及鈣鈦礦的熱降解機理(2/2)

Project Details

Description

Background: Dye-sensitized solar cells (DSCs) are promising inexpensive photovoltaic architectures capable of achieving large areas with transparency and flexibility. Dye sensitizers play critical roles in light-harvesting and electron injections. Perovskite solar cells (PSCs) were first reported in 2009 with 3% efficiency; within a few years, their efficiency reached over 20%.Motivations: Dye sensitizers with panchromatic absorption extending into the near-IR region are needed to enhance solar-to-electric power conversion efficiencies (PCEs). However, achieving panchromatic absorption by a single dye sensitizer remains challenged. The most crucial and challenging task is to improve the limited lifetimes of PSCs under their operating environments to ensure their long-term usage. Developing a robust understanding of the thermal degradation mechanism of PSCs is paramount to their future success as a commercial technology.Preliminary Results: (i). The near-IR absorption of Os-complexes activated by spin-orbit coupling through “heavy” Os atom and intensity borrowing from ancillary ligands is mainly 3MLCT transition. Moreover, the near-IR absorption of Os-complexes significantly contribute to the photocurrent of the cells. (ii). Ancillary ligands (Cl and PPh(OMe)2) of DX1 contribute slightly to the electronic transition and thus heavy Ru atom dominates the electronic transition leading to SOC-activated longer wavelength 3MLCT transitions. (iii). The reversibility of thermal degradation reactions of PSCs significantly affects the degradation routes.Methodology: Electronic transition energies were calculated through TDDFT including the perturbative spin-orbit coupling approach with a relativistic Hamiltonian based on the zeroth-order regular approximation (ZORA) using the Becke three-parameter Lee–Yang–Parr (B3LYP). For the PSC model, a slab model of the cation-halide-terminated (100) surface from the bulk structure with two layers. The cation-halide-terminated surface model was expanded to a 2 2 surface supercells. The reciprocal space integration was performed over a 4 4 1 Monkhorst–Pack k-point grid.Objectives: (i). Understand, enhance, and design the spin-forbidden transitions in the near-IR absorption for DX1-based metal complexes, (ii). Design metalloporphyrin-based sensitizers exhibiting MLCT and near-IR absorptions simultaneously, and (iii). Delineating thermal degradation reaction energy profile of FA-based perovskites to understand the thermal degradation kinetic mechanism of PSCs.
StatusFinished
Effective start/end date1/08/2231/10/23

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
  • SDG 11 - Sustainable Cities and Communities
  • SDG 13 - Climate Action
  • SDG 17 - Partnerships for the Goals

Keywords

  • Dye-sensitized Solar cells
  • Perovskite solar cells
  • Near-IR absorption
  • Panchromatic Absorption
  • Thermal Degradation of Perovskites
  • Spin-Orbit Coupling
  • Spin-Forbidden Transition

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