Periodic Reporting for period 1 - TADF-LDS (Visually Attractive Photovoltaic Panels without Efficiency Loss)
Reporting period: 2021-09-01 to 2023-08-31
Aesthetics of solar cells have become more important in recent years and academic, and industrial implementation of photovoltaics can be boosted by the implementation of PV modules free of aesthetic constraints. To date, however, this has always been accompanied by negative consequences on cost and performance.
The proposed project involves two distinct and interrelated challenges and thereby aims to address the aesthetic constraints of PV panels that can limit the wide acceptance of PV panels in residential applications and solar-powered products. First, we design and synthesize a unique new class of lanthanide luminescent downshifting (LDS) based molecules, by fundamentally changing the spectral absorption range of sensitizer antennae ligands. We also emphasize that this new approach will also be applicable to organo-lanthanide emitters in other fields, such that our concept has the potential for a broad paradigm shift across other luminescence applications.
Alongside this, we introduce a viable technical approach based on LDS materials toward fabricating brightly coloured, graphically designed, and aesthetically pleasing customizable solar panels in a practical system, without compromising efficiency and in a cost-effective way. For this, we have initially pioneered a method for fabricating stand-alone LDS films in any colours and designs and laminated these onto solar cells to give highly appealing appearance. A key advantage of our method is that coloured layers can be retrospectively added to the desired solar cells/panels, which gives high flexibility in terms of colour, design patterns, shape, and applications. Furthermore, the LDS films can in principle be simply replaced many times during the lifetime of a PV module. This enables the panel appearance to be updated, avoids complicating highly-optimised manufacturing processes, and avoids issues of dye bleaching over time, issues which have been barriers to LDS applications in the past.
To meet these aims, the specific objectives of the project are achieved
1) Design, computational (DFT) screening, synthesis, structural and optical characterization of new TADF ligands and lanthanide complexes as a new class of efficient LDS materials. For ligand molecules, frontier molecular orbitals, singlet (S1) and triplet (T1) energies will be calculated to deduce the TADF characteristics. Synthetic protocols are developed for both ligands and lanthanide complexes. Photo-physical properties of the newly synthesized lanthanide emitters are investigated using UV-Vis absorption and steady-state and time-resolved photoluminescence (PL) spectroscopic measurements.
2) Protocols for optimized developing LDS films for solar panels to impart colour and designs in a cost-effective way. This involves printing of films and fixing films onto the the PV panels.
The developments and progress in any technologies begin from academic research. New advancements in the PV industry start from new materials, the researchers and industry working on different aspects getting the opportunity to explore new devices. Precisely our project aims to develop a novel class of luminescent downshifting materials (LDS) and explore the much neglected potential of LDS materials in improving the aesthetic appearance of solar panels. The proposed developments in this project will lead to the implementation of a highly innovative technology in the PV market
The proposed project involves two distinct and interrelated challenges and thereby aims to address the aesthetic constraints of PV panels that can limit the wide acceptance of PV panels in residential applications and solar-powered products. First, we design and synthesize a unique new class of lanthanide luminescent downshifting (LDS) based molecules, by fundamentally changing the spectral absorption range of sensitizer antennae ligands. We also emphasize that this new approach will also be applicable to organo-lanthanide emitters in other fields, such that our concept has the potential for a broad paradigm shift across other luminescence applications.
Alongside this, we introduce a viable technical approach based on LDS materials toward fabricating brightly coloured, graphically designed, and aesthetically pleasing customizable solar panels in a practical system, without compromising efficiency and in a cost-effective way. For this, we have initially pioneered a method for fabricating stand-alone LDS films in any colours and designs and laminated these onto solar cells to give highly appealing appearance. A key advantage of our method is that coloured layers can be retrospectively added to the desired solar cells/panels, which gives high flexibility in terms of colour, design patterns, shape, and applications. Furthermore, the LDS films can in principle be simply replaced many times during the lifetime of a PV module. This enables the panel appearance to be updated, avoids complicating highly-optimised manufacturing processes, and avoids issues of dye bleaching over time, issues which have been barriers to LDS applications in the past.
To meet these aims, the specific objectives of the project are achieved
1) Design, computational (DFT) screening, synthesis, structural and optical characterization of new TADF ligands and lanthanide complexes as a new class of efficient LDS materials. For ligand molecules, frontier molecular orbitals, singlet (S1) and triplet (T1) energies will be calculated to deduce the TADF characteristics. Synthetic protocols are developed for both ligands and lanthanide complexes. Photo-physical properties of the newly synthesized lanthanide emitters are investigated using UV-Vis absorption and steady-state and time-resolved photoluminescence (PL) spectroscopic measurements.
2) Protocols for optimized developing LDS films for solar panels to impart colour and designs in a cost-effective way. This involves printing of films and fixing films onto the the PV panels.
The developments and progress in any technologies begin from academic research. New advancements in the PV industry start from new materials, the researchers and industry working on different aspects getting the opportunity to explore new devices. Precisely our project aims to develop a novel class of luminescent downshifting materials (LDS) and explore the much neglected potential of LDS materials in improving the aesthetic appearance of solar panels. The proposed developments in this project will lead to the implementation of a highly innovative technology in the PV market
1) Design and computational (DFT) screening of various classes of organic donor-acceptor molecules to find lead TADF ligands: Donor-acceptor (D-A) systems containing chelating units are designed as TADF ligand molecules, the frontier molecular orbitals, singlet (S1), and triplet (T1) energies are calculated by DFT/TD-DFT to deduce the TADF characteristics. The lead TADF molecules with appropriate energy matching to sensitize Eu(III) efficiently were taken for developing Eu(III) complexes with TADF photosensitizers. First, three lead TADF ligands and their Eu(III) complexes were synthesized and structurally characterized. Photo-physical properties of the newly synthesized lanthanide emitters were investigated using Uv-Vis absorption, steady-state, and time-resolved photoluminescence (PL) spectroscopic measurements. The TADF ligand co-sensitized tris(β-diketonate)Eu(III) complexes showed bright red luminescence with an outstand-ing sensitization efficiency of 90-94% and Φtot of 79-85% in poly-(methyl methacrylate) encapsulated films. The excited state energy transfer mechanism is illustrated using DFT/TD-DFT calculations. This rational approach of efficiently sensitizing lanthanides with TADF ligands demonstrates their great potential for applications in imaging and optical communications.2
2) A complete literature survey on LDS materials and their effect on solar cells was carried out and drew the conclusion that the efficiency increase with an additional LDS layer in PV cells (typical-ly 0.2%- 4.0% relative increase) is not high enough to compensate the extra cost associated with its introduction. Further few reports on developing colored solar panels using LDS materials were also summarised. The work on establishing a protocol for developing a standalone LDS film for visually appealing solar panels using LDS materials was carried out by a colleague in the group. All the data were collected for this work, and results were analyzed, interpreted, and communicated as a perspective article. This work emphasized the importance of our new approach of focusing also on the aesthetics of solar panels, rather than only efficiency.
2) A complete literature survey on LDS materials and their effect on solar cells was carried out and drew the conclusion that the efficiency increase with an additional LDS layer in PV cells (typical-ly 0.2%- 4.0% relative increase) is not high enough to compensate the extra cost associated with its introduction. Further few reports on developing colored solar panels using LDS materials were also summarised. The work on establishing a protocol for developing a standalone LDS film for visually appealing solar panels using LDS materials was carried out by a colleague in the group. All the data were collected for this work, and results were analyzed, interpreted, and communicated as a perspective article. This work emphasized the importance of our new approach of focusing also on the aesthetics of solar panels, rather than only efficiency.
1) A luminescent strain-sensitive film was developed using the Eutta3DPEPO complex. The Eu(III) complex was synthesized and structurally characterized by NMR and HRMS. Systematic studies were carried out on the luminescent changes of the Eutta3DPEPO complex, luminescence intensity, decay kinetics, and luminescence quantum yields were measured by increasing and decreasing the strain load. These materials can find potential applications in structural health monitoring devices.
2) A highly luminescent triphenyl amine appended terpyridine (TPA-TPY) charge transfer ligand was synthesized as a new chelating ligand for sensitizing lanthanides. Theoretical calculations showed that the TPA-TPY ligand can act as an efficient co-photosensitizer for Eu(III). The (TPA-TPY)Eutta3 and (TPA-TPY)Euhfa3 complexes were synthesized and structurally characterized. The complexes showed characteristic Eu(III) centered luminescence around 611 nm. The potential application of this molecule as a luminescent sensor will be explored.
2) A highly luminescent triphenyl amine appended terpyridine (TPA-TPY) charge transfer ligand was synthesized as a new chelating ligand for sensitizing lanthanides. Theoretical calculations showed that the TPA-TPY ligand can act as an efficient co-photosensitizer for Eu(III). The (TPA-TPY)Eutta3 and (TPA-TPY)Euhfa3 complexes were synthesized and structurally characterized. The complexes showed characteristic Eu(III) centered luminescence around 611 nm. The potential application of this molecule as a luminescent sensor will be explored.