Artificial Light-harvesting Systems Research Articles

A sequential light-harvesting system with thermosensitive colorimetric emission in both aqueous solution and hydrogel.

Inspired by natural photosynthetic systems that feature both sequential energy transfer and temperature response, we herein report an artificial thermosensitive sequential light-harvesting system (LHS) based on an amphiphilic molecule TPEO. It self-assembles into fluorescent nanoparticles in water and shows tunable LCST behavior. By loading ESY as the first acceptor and NiR as the second acceptor into the nanoparticles, an artificial LHS with two-step FRET was successfully constructed. Interestingly, the system exhibits thermosensitive colorimetric fluorescence in both aqueous solution and hydrogel by taking advantage of a combination of LCST and sequential FRET.

A multifunctional organogel for constructing artificial light harvesting systems with excellent energy transfer efficiency

Fluorescent gels with excellent physical properties were synthesised using polyvinyl alcohol/telmisartan. An artificial light-harvesting system with high energy-transfer efficiency and antenna effect was constructed by adding acridine yellow G and rhodamine B.

An anti-freeze fluorescent organogel with rapid shape-forming properties for constructing artificial light harvesting systems used in extremely cold environments.

Using polyvinyl alcohol (PVA) and perylene-3,9-dicarboxylic acid (PDA) as raw materials, a new anti-freeze (-50 °C) fluorescent organogel with rapid shape-forming (2 h) properties was synthesised based on a certain proportion of the binary solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Then, an artificial light-harvesting system (ALHS) used in extremely cold environments was successfully constructed by mixing fluorescent dyes sulphorhodamine101 (SR101) and rhodamine 6G (R6G) into them as acceptors.

Double-cavity cucurbiturils: synthesis, structures, properties, and applications.

Double-cavity Q[n]s are relatively new members of the Q[n] family and have garnered significant interest due to their distinctive structures and novel properties. While they incorporate n glycoluril units, akin to their single-cavity counterparts, their geometry can best be described as resembling a figure-of-eight or a handcuff, distinguishing them from single-cavity Q[n]s. Despite retaining the core molecular recognition traits of single-cavity Q[n]s, these double-cavity variants introduce fascinating new attributes rooted in their distinct configurations. This overview delves into the synthesis, structural attributes, properties, and intriguing applications of double-cavity Q[n]s. Some of the applications explored include their role in supramolecular polymers, molecular machinery, supra-amphiphiles, sensors, artificial light-harvesting systems, and adsorptive separation materials. Upon concluding this review, we discuss potential challenges and avenues for future development and offer valuable insights for other scholars working in this area with the aim of stimulating further exploration and interest.

Biomimetic light-harvesting antennas via the self-assembly of chemically programmed chlorophylls.

The photosynthetic pigment "chlorophyll" possesses attractive photophysical properties, including efficient sunlight absorption, photoexcited energy transfer, and charge separation, which are advantageous for applications for photo- and electro-functional materials such as artificial photosynthesis and solar cells. However, these functions cannot be realized by individual chlorophyll molecules alone; rather, they are achieved by the formation of sophisticated supramolecules through the self-assembly of the pigments. Here, we present strategies for constructing and developing artificial light-harvesting systems by mimicking photosynthetic antenna complexes through the highly ordered supramolecular self-assembly of synthetic dyes, particularly chlorophyll derivatives.

A sequential artificial light-harvesting system based on a metallacycle for sensitive detection of biothiols

A cascaded artificial light-harvesting system based on the platinum(ii) metallacycle was constructed, which displayed high sensitivity and specificity for biothiols.

Carbazole-based artificial light-harvesting system for photocatalytic cross-coupling dehydrogenation reaction.

A carbazole-based artificial light-harvesting system (LHS) was successfully fabricated based on the supramolecular assembly of AIE-enhanced donor (CTD), water-soluble phosphate-pillar[5]arene (WPP5), and eosin Y (ESY) acceptor. The formed WPP5-CTD possessed remarkable AIE emission, featuring an ideal energy donor for light harvesting. After encapsulation of ESY, the energy of WPP5-CTD was efficiently transferred to ESY in WPP5-CTD-ESY, and the antenna effect was 38.5, which was much higher than that of recently reported LHSs. Notably, WPP5-CTD-ESY was successfully utilized as a photocatalyst to realize the cross-coupling dehydrogenation reaction of diphenylphosphine oxide and benzothiazole derivatives, suggesting great potential for aqueous photocatalytic applications of this LHS.

Switchover from singlet oxygen to superoxide radical through a photoinduced two-step sequential energy transfer process.

The competitive nature of type II photosensitizers in the transfer of excitation energy for the generation of singlet oxygen (1O2) presents significant challenges in the design of type I photosensitizers to produce the superoxide anion radical (O2˙-). In this study, we present an efficient method for the direct transformation of type II photosensitizers into type I photosensitizers through the implementation of an artificial light-harvesting system (ALHSs) involving a two-step sequential energy transfer process. The designed supramolecular complex (DNPY-SBE-β-CD) not only has the ability to generate 1O2 as type II photosensitizers, but also demonstrates remarkable fluorescence properties in aqueous solution, which renders it an efficient energy donor for the development of type I photosensitizers ALHSs, thereby enabling the efficient generation of O2˙-. Meanwhile, to ascertain the capability and practicality of this method, two organic reactions were conducted, namely the photooxidation reaction of thioanisole and oxidative hydroxylation of arylboronic acids, both of which display a high level of efficiency and exhibit significant catalytic performance. This work provides an efficient method for turning type II photosensitizers into type I photosensitizers by a two-step sequential energy transfer procedure.

A Supramolecular Artificial Light-Harvesting System with Excitation Energy and Electron Transfer

A Supramolecular Artificial Light-Harvesting System with Excitation Energy and Electron Transfer

Barbier Polymerization-Induced Emission towards Fully Substituted Polyethylene Analogues with Non-Traditional Intrinsic Luminescence.

The properties of polyethylene are highly dependent on the variety and quantity of substitutions. Generally, polyethylene can only be fully substituted with fluorine atoms, mainly e. g., polytetrafluoroethylene and nafion, because atomic radius of fluorine atom is small enough. The preparation of fully substituted polyethylene analogues (FSPEA) and their non-traditional intrinsic luminescence (NTIL) are attractive, especially for substitutions with relatively larger atomic radii than a fluorine atom. Here, Barbier polymerization-induced emission (PIE) is demonstrated as a universal method for the molecular design of NTIL type FSPEAs with intriguing aggregation-induced emission (AIE) behaviors. Through Barbier polymerization of diphenyldichloromethane and different peroxyesters in the presence of Mg in one pot, a series of FSPEAs, including polytriphenylethanol (PTPE), polydiphenylfurylethanol (PDPFE), polydiphenylthiophenylethanol (PDPTE) and polydiphenylnaphthylethanol (PDPNE) have been successfully prepared. Further potential applications for explosive detection, artificial light-harvesting system and white phosphor-converted light-emitting diode are investigated. Therefore, this work opens up a new approach for the molecular design of FSPEA with non-conjugated luminescence, which may cause inspirations to different research fields like polyolefin and luminescent materials.

Construction of artificial light-harvesting system based on host-guest interactions of sulfobutylether-β-cyclodextrin and its application in photocatalysis

Light-harvesting systems (LHSs) play an important role in natural photosynthesis for converting light energy into chemical energy, which paves a prospective way for the exploitation of renewable energy resources. In this work, two artificial light-harvesting systems with an efficient energy transfer were constructed successfully in the aqueous media based on sulfobutylether-β-cyclodextrin (β-CD) and curcumin (Cur) through host-guest interactions, in which two different fluorescence dyes, sulforhodamine (SR101) and Nile blue (NiB) were employed as energy acceptors. The obtained artificial LHSs can achieve an efficient energy transfer process from β-CD+Cur to SR101 or NiB with energy transfer efficiencies of up to 16.3% and 15.8%, respectively. The energy harvested by the acceptors (SR101 and NiB) was used for photocatalysis in the aqueous phase dehalogenation of the α-bromoacetophenone reaction with a yield of up to 80%.

Efficient artificial light-harvesting systems based on organic small microcrystals in aqueous suspension

Four efficient artificial light-harvesting systems have been developed in the present work. They assemble sodium dodecyl sulphate (SDS) with organic small molecule chromophores to synthesize microcrystals to mimic chlorophyll. In microcrystals, the chromophores are ordered through intermolecular dipole-dipole interactions, which results in efficient energy transfer. In the D-2/A-2 light-harvesting system, the donor concentrates excitation energy from 500 chromophores into a single acceptor with a relative high energy transfer efficiency (86%) and an antenna efficiency (33). The microcrystals exhibit high energy harvesting performance and act as an ideal framework for artificial light-harvesting systems.

Host-Guest Complexes of Pillar[5]arene as Components for Supramolecular Light-Harvesting Systems with Tunable Fluorescence.

A guest molecule containing a short alkyl spacer between the tetraphenylethylene group and the methylpyridinium group was designed and synthesized. After complexation with a water-soluble pillar[5]arene, the resulting host-guest complex can further self-assemble into fluorescence-emitting nanoparticles in water. By loading a commercially available dye Rhodamine 6G into the nanoparticles, an efficient artificial light-harvesting system with high donor/acceptor ratios (>400/1) was successfully constructed. The obtained systems show considerable antenna effects with values of more than 10 times. The system also exhibits tunable fluorescence emission behavior and can be used as a fluorescent ink for information encryption.

Three–step cascaded artificial light–harvesting systems with tunable efficiency based on metallacycles

It is still challenging to develop multi–step cascaded artificial light–harvesting systems (ALHSs) with tunable efficiency. Here, we designed novel cascaded ALHSs with AIE–active metallacycles as the light–harvesting antenna, Eosin Y (ESY) and sulforhodamine 101 (SR101) as conveyors, near–infrared emissive chlorin–e6 (Ce6) as the final acceptor. The close contact and fair spectral overlap between donor and acceptor molecules at each level ensured the efficient sequential three–step energy transfer. The excited energy was sequentially and efficiently funneled to Ce6 along the cascaded line MTPEPt1 → ESY → SR101 → Ce6. Additionally, a unique strategy for regulating the efficiency of ALHS was illustrated by adjusting hydrophilic and hydrophobic interactions.

Bio-templated energy transfer system for constructing artificial light-harvesting antennae, white light generation, and photonic nanowires

Developing environmentally friendly, sustainable, and biocompatible artificial light-harvesting systems has become an essential area of research to understand natural light-harvesting processes involving multistep resonance energy transfer and building efficient energy conversion systems related to energy and optoelectronic applications. In this direction, bio-scaffolded artificial energy transfer systems for panchromatic light collection and sequential energy transfer have fascinated the scientific community. In this review, we have discussed what the dynamic structure and intrinsic physical properties of biomolecules like deoxyribonucleic acid, proteins, and peptides can provide for the development of new optical devices, sustainable and environmentally friendly white emitting materials, and cascaded energy transfer systems for energy harvesting from light. In doing so, we have highlighted some of the recent advances in bio-scaffolds as a platform for the assembly of different types of donor–acceptor chromophores involved in fluorescence energy transfer.

Construction of aggregation-induced emission photosensitizers through host-guest interactions for photooxidation reaction and light-harvesting

In the present work, we have designed and synthesized a triphenylamine modified cyanophenylenevinylene derivative (TPCI), which can self-assembly with cucurbit[6]uril (CB[6]) and cucurbit[8]uril (CB[8]) through host-guest interactions to form supramolecular complexes (TPCI-CB[6]) and supramolecular polymers (TPCI-CB[8]) in the aqueous solution. The supramolecular assemblies of TPCI-CB[6] and TPCI-CB[8] not only exhibited high singlet oxygen (1O2) production efficiency as photosensitizers, but also realized the application in the construction of artificial light-harvesting systems due to the excellent fluorescence properties in the aqueous solution. The production efficiency of 1O2 has been effectively improved after the addition of CB[6] and CB[8] for TPCI, which were applied as efficient photosensitizers in the photooxidation reactions of thioanisole and its derivatives with the highest yield of 98% in the aqueous solution. The excellent fluorescence properties of TPCI-CB[6] and TPCI-CB[8] can be used as energy donors in artificial light-harvesting systems with energy acceptors sulforhodamine 101 (SR101) and cyanine dye 5 (Cy5), in which one-step energy transfer processes of TPCI-CB[6]+SR101 and TPCI-CB[8]+Cy5, and a two-step sequential energy transfer process of TPCI-CB[6]+SR101+Cy5 were constructed to simulate the natural photosynthesis system.

Protein-Based Model for Energy Transfer between Photosynthetic Light-Harvesting Complexes Is Constructed Using a Direct Protein-Protein Conjugation Strategy.

Photosynthetic organisms utilize dynamic and complex networks of pigments bound within light-harvesting complexes to transfer solar energy from antenna complexes to reaction centers. Understanding the principles underlying the efficiency of these energy transfer processes, and how they may be incorporated into artificial light-harvesting systems, is facilitated by the construction of easily tunable model systems. We describe a protein-based model to mimic directional energy transfer between light-harvesting complexes using a circular permutant of the tobacco mosaic virus coat protein (cpTMV), which self-assembles into a 34-monomer hollow disk. Two populations of cpTMV assemblies, one labeled with donor chromophores and another labeled with acceptor chromophores, were coupled using a direct protein-protein bioconjugation method. Using potassium ferricyanide as an oxidant, assemblies containing o-aminotyrosine were activated toward the addition of assemblies containing p-aminophenylalanine. Both of these noncanonical amino acids were introduced into the cpTMV monomers through amber codon suppression. This coupling strategy has the advantages of directly, irreversibly, and site-selectively coupling donor with acceptor protein assemblies and avoids cross-reactivity with native amino acids and undesired donor-donor or acceptor-acceptor combinations. The coupled donor-acceptor model was shown to transfer energy from an antenna disk containing donor chromophores to a downstream disk containing acceptor chromophores. This model ultimately provides a controllable and modifiable platform for understanding photosynthetic interassembly energy transfer and may lead to the design of more efficient functional light-harvesting materials.

Carbon dot-based artificial light-harvesting systems with sequential energy transfer and white light emission for photocatalysis

In this work, we designed and synthesized cationic carbon dots (CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system (LHS) by employing the energy-matching dyes eosin Y disodium salt (EY) and sulforhodamine 101 (SR101), which could regulate the white light emission (Commission Internationale de lʼEclairage (CIE) coordinate: (0.30, 0.31)) with the energy transfer efficiency (ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission (0.32, 0.28) can be constructed directly using CDs and dye solvent 43 (SR) with ΦET and antenna effect (AE) of 48.8% and 6.5, respectively. More importantly, CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of 90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.

Artificial stepwise light harvesting system in water constructed by quadruple hydrogen bonding supramolecular polymeric nanoparticles

Stepwise energy transfer is ubiquitous in natural photosynthesis, which greatly promotes the widespread use of solar energy. Herein, we constructed a supramolecular light harvesting system based on sequential energy transfer through the hierarchical self-assembly of M, which contains a cyanostilbene core flanked by two ureidopyrimidinone motifs, endowing itself with both aggregation-induced emission behavior and quadruple hydrogen bonding ability. The monomer M can self-assemble into hydrogen bonded polymers and then form supramolecular polymeric nanoparticles in water through a mini-emulsion process. The nanoparticles were further utilized to encapsulate the relay acceptor ESY and the final acceptor NDI to form a two-step FRET system. Tunable fluorescence including a white-light emission was successfully achieved. Our work not only shows a desirable way for the fabrication of efficient two-step light harvesting systems, but also shows great potential in tunable photoluminescent nanomaterials.

Near-Infrared Emissive Cascaded Artificial Light-Harvesting System with Enhanced Antibacterial Efficiency.

Combination of platinum(II) metallacycles and photodynamic inactivation presents a promising antibacterial strategy. Herein, a cascaded artificial light-capturing system is developed in which an aggregation-induced emission-active platinum(II) metallacycle (PtTPEM) is utilized as the antenna, sulforhodamine 101 (SR101) as a key conveyor, and the near-infrared emissive photosensitizer Chlorin-e6 (Ce6) as the final energy acceptor. The well-dispersed Ce6 in the proximity of energy donors not only avoids self-quenching in the physiological environment but also contributes to energy transfer from donor to acceptor, thereby significantly improving the 1 O2 generation ability of the light-harvesting system under white light irradiation. By integrating the platinum(II) metallacycle and 1 O2 , a more efficient synergistic antibacterial effect is achieved at low concentrations, along with a significant decrease in dark toxicity caused by PtTPEM.