Predicting the efficiency of luminescent solar concentrators for solar energy harvesting using machine learning.

Building-integrated photovoltaics (BIPV) is an emerging technology in the solar energy field. It involves using luminescent solar concentrators to convert traditional windows into energy generators by utilizing light harvesting and conversion materials. This study investigates the application of machine learning (ML) to advance the fundamental understanding of optical material design. By leveraging accessible photoluminescent measurements, ML models estimate optical properties, streamlining the process of developing novel materials, offering a cost-effective and efficient alternative to traditional methods, and facilitating the selection of competitive materials. Regression and clustering methods were used to estimate the optical conversion efficiency and power conversion efficiency. The regression models achieved a Mean Absolute Error (MAE) of 10%, which demonstrates accuracy within a 10% range of possible values. Both regression and clustering models showed high agreement, with a minimal MAE of 7%, highlighting the efficacy of ML in predicting optical properties of luminescent materials for BIPV.

Three robust Cd(II) coordination polymers as bifunctional luminescent probes for efficient detection of pefloxacin and Cr2O72- in water.

The accurate and rapid detection of antibiotics and heavy-metal-based toxic oxo-anions in water media employing coordination polymers (CPs) as luminescent probes has attracted a lot of attention. Three new Cd(II)-based ternary CPs derived from first-presented L ligands, including [Cd(DCTP)(L)(OH)]n (1), [Cd(TBTA)(L)(OH)]n (2), and [Cd(NPHT)(L)(H2O)]n (3) (L = 2-((1H-imidazol-1-yl)methyl)-5,6-dimethyl-1H-benzo[d]imidazole, H2DCTP = 2,5-dichloroterephthalic acid, H2TBTA = tetrabromoterephthalic acid and H2NPHT = 3-nitrophthalic acid), were successfully assembled and characterized. 1 and 2 show 2D hcb layers, which can be further extended into a 3D supramolecular framework via classic hydrogen bonding interactions. 3 features a 1D double chain that ultimately spreads into a 2D network through weak hydrogen bonding interactions. With the advantages of high stability and excellent luminescent properties, the three CPs display high sensitivity, selectivity, and good anti-interference for the sensing of pefloxacin (PEF) and Cr2O72- ions (LOD values toward PEF: 3.82 × 10-7 mol L-1 for 1, 4.06 × 10-7 mol L-1 for 2, and 1.36 × 10-8 mol L-1 for 3, and toward Cr2O72- ions: 5.97 × 10-7 mol L-1 for 1, 5.87 × 10-7 mol L-1 for 2, and 8.21 × 10-8 mol L-1 for 3). These CPs are the first examples of bifunctional luminescent sensors to detect PEF and Cr2O72- in aqueous solutions. The luminescence quenching mechanisms are explored in detail.

A comprehensive dataset of photonic features on spectral converters for energy harvesting.

Building integrated photovoltaics is a promising strategy for solar technology, in which luminescent solar concentrators (LSCs) stand out. Challenges include the development of materials for sunlight harvesting and conversion, which is an iterative optimization process with several steps: synthesis, processing, and structural and optical characterizations before considering the energy generation figures of merit that requires a prototype fabrication. Thus, simulation models provide a valuable, cost-effective, and time-efficient alternative to experimental implementations, enabling researchers to gain valuable insights for informed decisions. We conducted a literature review on LSCs over the past 47 years from the Web of ScienceTM Core Collection, including published research conducted by our research group, to gather the optical features and identify the material classes that contribute to the performance. The dataset can be further expanded systematically offering a valuable resource for decision-making tools for device design without extensive experimental measurements.

A highly efficient lanthanide coordination polymer luminescent material for the multi-task detection of environmental pollutants.

It is challenging to explore novel-structure lanthanide coordination polymers (Ln-CPs) for sensing environmental pollutants. Herein, we designed and synthesized an organic bridging linker 3-(carboxymethoxy)-1-(carboxymethyl) pyrazole-4-carboxylic acid (H3ccpc), and then successfully prepared and characterized a novel Ln-CP, namely [Tb2(ccpc)2(H2O)6]·1.5H2O (ccpcTb). Structural analysis indicates that ccpcTb exhibits a two-dimensional structure, in which Tb ions are in an eight-coordinated environment. The photoluminescence performance of ccpcTb was discussed in detail. The ccpcTb displays bright green luminescence and behaves as a multi-responsive luminescent sensor toward Fe3+ ions, Cr2O72- ions and 2,4,6-trinitrophenol with high selectivity and low detection limits. Furthermore, the possible luminescence sensing mechanisms have been addressed in detail. The luminescence quenching mechanism of sensing Fe3+ and Cr2O72- is attributed to the energy competitive absorption, while that of sensing TNP is due to the synergistic effect of energy competitive absorption and photo-induced electron transfer.

Engineering highly dispersed AgI nanoparticles on hierarchical In2S3 hollow nanotube to construct Z-scheme heterojunction for efficient photodegradation of insecticide imidacloprid.

Increasing the exposure of active sites and improving the intrinsic activity are necessary considerations for designing a highly efficient photocatalyst. Herein, an In2S3/AgI stable Z-scheme heterojunction with highly dispersed AgI nanoparticles (NPs) is synthesized by the mild self-templated and in-situ ion exchange strategy. Impressively, the optimized In2S3/AgI-300 Z-scheme heterojunction exhibits superior photodegradation activity (0.020 min-1) for the decomposition of insecticide imidacloprid (IMD), which is extremely higher than that of pure In2S3 (0.002 min-1) and AgI (0.013 min-1). Importantly, the three-dimensional excitation-emission matrix (3D EEMs) fluorescence spectra, high-resolution mass spectrometry (HRMS), the photoelectrochemical tests, radical trapping experiment, and electron spin resonance (ESR) technique are performed to clarify the possible degradation pathway and mechanism of IMD by the In2S3/AgI-300 composite. The enhanced photocatalytic performance is attributed to the highly dispersed AgI NPs on hierarchical In2S3 hollow nanotube and the construction of In2S3/AgI Z-scheme heterojunction, which can not only increase active site exposure, but also improve its intrinsic activity, facilitating rapid charge transfer rate and excellent electron-hole pairs separation efficiency. Meanwhile, the practical application potential of the In2S3/AgI-300 composite is systematically investigated. This study opens a new insight for designing catalysts with high photocatalytic performance through a convenient approach.

An autonomous power temperature sensor based on window-integrated transparent PV using sustainable luminescent carbon dots.

The energy efficiency of buildings can be significantly improved through the use of renewable energy sources. Luminescent solar concentrators (LSCs) appear to be a solution for integrating photovoltaic (PV) devices into the structure of buildings (windows, for instance) to enable low-voltage devices to be powered. Here, we present transparent planar and cylindrical LSCs based on carbon dots in an aqueous solution and dispersed in organic-inorganic hybrid matrices, which present photoluminescent quantum yield values up to 82%, facilitating an effective solar photon conversion. These LSCs showed the potencial for being incorporated as building windows due to an average light transmittance of up to ∼91% and color rendering index of up to 97, with optical and power conversion efficiency values of 5.4 ± 0.1% and 0.18 ± 0.01%, respectively. In addition, the fabricated devices showed temperature sensing ability enabling the fabrication of an autonomous power mobile temperature sensor. Two independent thermometric parameters were established based on the emission and the electrical power generated by the LSC-PV system, which could both be accessed by a mobile phone, enabling mobile optical sensing through multiparametric thermal reading with relative sensitivity values up to 1.0% °C-1, making real-time mobile temperature sensing accessible to all users.

Spectroscopic properties and fluorescent recognition of dye sensitized layered lutetium-terbium hydroxides.

The layered rare earth hydroxides have attracted increasing interests due to their diverse chemical composition and tunable spectroscopic properties. In this paper, a novel Tb3+ activated layered lutetium hydroxide (LLuH:Tb) was fabricated, in which the inorganic NO3- ions were ion-exchanged with organic (ibuprofen or dodecylsulfonate) anions. After the ion-exchange reaction, the organic anions intercalated LLuH:Tb showed the distinct lamellar structure with the interlayer distance of about 2.56 nm, confirming the formation of inorganic/organic hybrid assembly. The dye ibuprofen-intercalated hybrid effectively promoted the characteristic 5D4 â†’ 7F5 green emission of Tb3+ in the host but failed to be exfoliated into nanosheet colloid. On the contrary, the dodecylsulfonate-intercalated hybrid was readily to be exfoliated into nanosheet colloid by dissolving in formamide solvent, but the green emission of Tb3+ was too weak to be observed. To take advantage of their respective merits and explore the practical uses, certain amounts of dye ibuprofen were directly added to the dodecylsulfonate-intercalated hybrid colloid. Excited with the ultraviolet light, the characteristic green fluorescence of Tb3+ was dramatically enhanced, indicating that the dye was a superior light-harvesting antenna to sensitize the activator Tb3+. The dye sensitized hybrid colloid was very stable at ambient temperature and exhibited excellent fluorescent recognition for Cu2+ ions over other metal ions in aqueous solution due to the large fluorescence quenching. The detection limit for Cu2+ ion reaches 7.63 × 10-7 mol/L, which is far lower than the limitation of Cu2+ in drinking water recommended by the World Health Organization (1.57 × 10-5 mol/L). The fluorescence enhanced/quenched sensor with excellent stability exhibits a high potential for the detection of Cu2+ in routine environmental water.

Sensitization of Mn2+ Luminescence by Eu2+: A Combined Study Using Optical Spectroscopy and Luminescence Dynamics Simulations.

Owing to the intriguing luminescent feature, Mn2+-doped materials have attracted a lot of attention. Unfortunately, their application potential is hampered by the parity-forbidden nature of Mn2+ 3d-3d transition, and the insufficient excitation light absorption is the main obstacle. Although the use of a sensitization strategy effectively addresses this issue, explicit knowledge of the sensitization mechanism is insufficient, severely limiting the improvement of Mn2+ luminescence performance in a wide range of materials. Herein, the sensitization of Mn2+ luminescence is investigated in Eu2+, Mn2+-codoped SrMgP2O7 which has the high luminescence efficiency upon UV excitation. The electronic transition properties of Eu2+ and Mn2+ are studied by VUV-UV-vis spectroscopy, and the sensitization mechanism is elucidated by luminescence dynamics simulations. Efforts are also made to evaluate the impact of temperature variation on the sensitization efficiency. Based on these discussions, the collaboration of high-efficiency Eu2+ → Mn2+ energy transfer via dipole-dipole interaction and suppression of Mn2+ luminescence loss results in the significant sensitization of Mn2+ luminescence in Eu2+, Mn2+-codoped materials, which are essentially associated with probable orbital hybridization and weak electron-vibration interaction, respectively. Current research provides a practical guideline for analyzing the luminescence sensitization effect in the donor-acceptor system, which facilitates the development of materials with unique optical features.

Two chemically robust Cd(II)-frameworks for efficient sensing of levofloxacin, benzaldehyde, and Fe3+ ions.

Two luminescent Cd(II)-organic frameworks [Cd2(L1)(tdc)2(H2O)]n (1) and [Cd(L2)0.5(tdc)]n (2) (L1 = 1,5-bis(1-(pyridine-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)pentane, L2 = 1,6-bis(1-(pyridine-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)hexane, and H2tdc = 2,5-thiophenedicarboxylic acid) were hydrothermally synthesized and characterized. 1 displays a rare binodal (3,4)-connected 2D cem-d network, while 2 exhibits a 3D mog (moganite) framework. The two MOFs are highly thermally durable and water-stable in a wide pH range from 3 to 12. Interestingly, 1 and 2 represent the first reported examples of multi-responsive probes based on MOFs for selectively detecting levofloxacin, benzaldehyde, and Fe3+ ions with reusability. The luminescence sensing mechanisms of the two CPs were explored in detail.

A robust 3D zinc(II)-organic framework for efficient dual detection of acetylacetone and Tb3+ ions.

There has been broad attention to the recognition and detection of ions and organic small molecules due to their essential roles in environmental systems. However, dual-functional probes have seldom been developed for sensing organic constituents and lanthanide ions. A new 3D pillared Zn(ii)-organic framework [Zn3(L)(DCTP)3]n (1) (L = 1,4-di(1H-benzo[d]imidazol-2-yl)butane and H2DCTP = 2,5-dichloroterephthalic acid) was hydrothermally synthesized and structurally characterized, and features a unique 3D 4,4,4,6-connected framework containing approximately 9.99 × 9.78 Å2 cubic channels. 1 displays excellent thermal and pH stability and can act as a novel "turn-on" fluorescent probe for highly selectively sensitizing Tb3+ ions through an "antenna effect". Furthermore, 1 is a dual-response fluorescent sensor for monitoring acetylacetone and Tb3+ ions with rapid response times (within 1 min), low limits of detection (LOD) (5.02 × 10-6/1.15 × 10-8 M, separately) and great anti-interference ability and recyclability towards the analytes. The related sensing mechanisms for detecting analytes are also investigated in detail.

A Copper(I)-Thioarsenate(III) Inorganic Framework Directed by [Ni(en)3]2.

One novel three-dimensional (3-D) copper(I)-thioarsenate(III) [Ni(en)3]Cu4As4S9 (1, en = ethylenediamine) has been solvothermally prepared with the utilization of the in situ formation of [Ni(en)3]2+ complex as structure-directing agent (SDA). 1 contains cubane-like [Cu8S12]16- clusters and rare tetrameric [As4S9]6- units, which are interconnected to generate the first example of a 3-D anionic framework [Cu4As4S9]n2n-, topologically identical to pyrite, and having large channels filled by [Ni(en)3]2+ complex cations. 1 is a potential wide-band-gap semiconductor with an energy gap of 1.91 eV that exhibits selectively photocatalytic degradation of methylene blue under visible-light irradiation. The density functional theory calculation, photocurrent response, and magnetic properties of 1 were also investigated.

Vanadoborates: cluster-based architectures, preparation and properties.

Crystalline polyoxovanadates (POVs) are a subclass of polyoxometalates with significance in chemical, physical and materials sciences. Recent studies revealed that the condensation of vanadate and borate fragments may yield a whole new class of POVs. These novel vanadoborates are typically prepared by high-temperature solid-state, boric acid flux or low-temperature hydrothermal techniques. The different connections of [VOx] (x = 4, 5, 6) and [BOx] (x = 3, 4) polyhedral units ultimately result in a fascinating variety of vanadoborate anionic clusters, which can be at the genesis of a myriad of one-dimensional (1-D), two-dimensional (2-D) and three-dimensional (3-D) polymeric architectures by way of either self-condensation or by forming covalent bonds with other metal ions or unsaturated metal complexes. This review summarizes, in a systematic structural approach, the most striking advances in the syntheses, structural features, and some properties of crystalline vanadoborates based on different [VxBy] and [VxByPz] clusters. It intends to provide meaningful and helpful guidance for the future preparation of new and functional vanadoborates.

Seven-Coordinate Tb3+ Complexes with 90% Quantum Yields: High-Performance Examples of Combined Singlet- and Triplet-to-Tb3+ Energy-Transfer Pathways.

Seven-coordinate, pentagonal-bipyramidal (PBP) complexes [Ln(bbpen)Cl] and [Ln(bbppn)Cl], in which Ln = Tb3+ (products I and II), Eu3+ (III and IV), and Gd3+ (V and VI), with bbpen2- = N,N'-bis(2-oxidobenzyl)-N,N'-bis(pyridin-2-ylmethyl)ethylenediamine and bbppn2- = N,N'-bis(2-oxidobenzyl)-N,N'-bis(pyridin-2-ylmethyl)-1,2-propanediamine, were synthesized and characterized by single-crystal X-ray diffraction analysis, alternating-current magnetic susceptibility measurements, and photoluminescence (steady-state and time-resolved) spectroscopy. Under a static magnetic field of 0.1 T, the Tb3+ complexes I and II revealed single-ion-magnet behavior. Also, upon excitation at 320 nm at 300 K, I and II presented very high absolute emission quantum yields (0.90 ± 0.09 and 0.92 ± 0.09, respectively), while the corresponding Eu3+ complexes III and IV showed no photoluminescence. Detailed theoretical calculations on the intramolecular energy-transfer rates for the Tb3+ products indicated that both singlet and triplet ligand excited states contribute efficiently to the overall emission performance. The expressive quantum yields, QLnL, measured for I and II in the solid state and a dichloromethane solution depend on the excitation wavelength, being higher at 320 nm. Such a dependence was rationalized by computing the intersystem crossing rates (WISC) and singlet fluorescence lifetimes (τS) related to the population dynamics of the S1 and T1 levels. Thin films of product II showed high air stability and photostability upon continuous UV illumination, which allowed their use as downshifting layers in a green light-emitting device (LED). The prototypes presented a luminous efficacy comparable with those found in commercial LED coatings, without requiring encapsulation or dispersion of II in host matrixes. The results indicate that the PBP environment determined by the ethylenediamine (en)-based ligands investigated in this work favors the outstanding optical properties in Tb3+ complexes. This work presents a comprehensive structural, chemical, and spectroscopic characterization of two Tb3+ complexes of mixed-donor, en-based ligands, focusing on their outstanding optical properties. They constitute good molecular examples in which both triplet and singlet excited states provide energy to the Tb3+ ion and lead to high values of QLnL.

Unique Two-Dimensional Indium Telluride Templated by a Rare Wheel-Shaped Heterobimetallic Mn/In Cluster.

A new indium telluride, [Mn4.78In2.22(ea)12]n[In9.79Mn0.21Te17]n (where Hea = ethanolamine), containing unprecedented nonsupertetrahedral [In9.79Mn0.21Te21] units is the first example of a two-dimensional indium telluride framework templated by a rare high-nuclearity wheel-shaped heterometallic [Mn4.78In2.22(ea)12]4.22+ cluster. The photocurrent response and magnetic properties were investigated.

Luminescence Thermometry on the Route of the Mobile-Based Internet of Things (IoT): How Smart QR Codes Make It Real.

Quick Response (QR) codes are a gateway to the Internet of things (IoT) due to the growing use of smartphones/mobile devices and its properties like fast and easy reading, capacity to store more information than that found in conventional codes, and versatility associated to the rapid and simplified access to information. Challenges encompass the enhancement of storage capacity limits and the evolution to a smart label for mobile devices decryption applications. Organic-inorganic hybrids with europium (Eu3+) and terbium (Tb3+) ions are processed as luminescent QR codes that are able to simultaneously double the storage capacity and sense temperature in real time using a photo taken with the charge-coupled device of a smartphone. The methodology based on the intensity of the red and green pixels of the photo yields a maximum relative sensitivity and minimum temperature uncertainty of the QR code sensor (293 K) of 5.14% · K-1 and 0.194 K, respectively. As an added benefit, the intriguing performance results from energy transfer involving the thermal coupling between the Tb3+-excited level (5D4) and the low-lying triplet states of organic ligands, being the first example of an intramolecular primary thermometer. A mobile app is developed to materialize the concept of temperature reading through luminescent QR codes.

White-Light Emitting Di-Ureasil Hybrids.

White-light emitting materials have emerged as important components for solid state lighting devices with high potential for the replacement of conventional light sources. Herein, amine-functionalized organic-inorganic di-ureasil hybrids consisting of a siliceous skeleton and oligopolyether chains codoped with lanthanide-based complexes, with Eu3+ and Tb3+ ions and 4,4'-oxybis(benzoic acid) and 1,10-phenanthroline ligands, and the coumarin 1 dye were synthesized by in situ sol⁻gel method. The resulting luminescent di-ureasils show red, green, and blue colors originated from the Eu3+, Tb3+, and C1 emissions, respectively. The emission colors can be modulated either by variation of the relative concentration between the emitting centers or by changing the excitation wavelength. White light emission is achieved under UV excitation with absolute quantum yields of 0.148 ± 0.015, 0.167 ± 0.017, and 0.202 ± 0.020 at 350, 332, and 305 nm excitation, respectively. The emission mechanism was investigated by photoluminescence and UV⁻visible absorption spectroscopy, revealing an efficient energy transfer from the organic ligands to the Ln3+ ions and the organic dye, whereas negligible interaction between the dopants is discerned. The obtained luminescent di-ureasils have potential for optoelectronic applications, such as in white-light emitting diodes.

High efficiency green OLEDs based on homoleptic iridium complexes with steric phenylpyridazine ligands.

A series of steric phenylpyridazine based homoleptic iridium(iii) complexes (1-3) have been synthesized with novel one-pot methods. Single X-ray structural analyses are conducted on complexes 1 and 2 to reveal their coordination arrangement. These complexes exhibit a very strong green phosphorescence emission with high quantum yields of over 64%. The relationship between photophysical properties and the substituent nature of the complexes is discussed by density functional theory (DFT) and time-dependent DFT. Self-quenching is significantly reduced for these complexes in solid even at very high concentrations because the sterically hindered bicyclo [2.2.2] oct-2-ene and m-substituted CF3 spacers in the phosphor molecules lead to minimum bimolecular interactions. Accordingly, the electroluminescence device based on complex 3 exhibits a maximum luminous efficiency of 64.1 cd A-1 with a high EQE of 25.2% at a high doping concentration of 15 wt%. Meanwhile, when neat 3 was adopted as the emitting layer, the non-doped green device gives a state-of-the-art EQE as high as 15.2% (40.1 cd A-1) along with CIE coordinates of (0.346, 0.599).

A novel 3-D cuprous iodide polymer with a high Cu/I ratio.

A novel 3-D cuprous iodide polymer [CuI(µ6-L)]n with a Cu/I ratio as high as 3 (1, H2L = 1,3-bis(2H-tetrazol-5-yl)benzene) has been hydrothermally synthesized. The 3-D framework of 1 is constructed by the linkages of rare 1-D cationic aggregates [CuI2+]n and anionic bi-tetrazolate bridges. 1 shows unusually thermochromic luminescent and photocatalytic properties, and its density functional theory calculation has also been studied.

Highly Efficient Luminescent Polycarboxylate Lanthanide Complexes Incorporated into Di-Ureasils by an In-Situ Sol-Gel Process.

In order to prepare efficient luminescent organic⁻inorganic hybrid materials embedded with a lanthanide (Ln3+) complex with polycarboxylate ligands, Ln3+-doped di-ureasils with 4,4-oxybis(benzoic acid) and 1,10-phenanthroline ligands were synthesized via an in-situ sol⁻gel route. The resulting hybrids were structurally, thermally, and optically characterized. The energy levels of the ligands and the host-to-ion and ligand-to-ion energy transfer mechanisms were investigated (including DFT/TD⁻DFT calculations). The results show that these Ln3+-based di-ureasil hybrids exhibit promising luminescent features, e.g., Eu3+-based materials are bright red emitters displaying quantum yields up to 0.50 ± 0.05. The luminescent color can be fine-tuned either by selection of adequate Ln3+ ions or by variation of the excitation wavelength. Accordingly, white light emission with CIE coordinates of (0.33, 0.35) under 310 nm irradiation was obtained.

A Series of Lanthanide-Germanate Oxo Clusters Decorated by 1,10-Phenanthroline Chromophores.

A series of lanthanide-germanate oxo clusters, [Ln8(phen)2Ge12(µ3-O)24T12(H2O)16]·2H2O [Ln = Dy (1a) and Er (1b); T = -CH2CH2COO- group; phen = 1,10-phenanthroline], [Ln8(phen)2Ge12(µ3-O)24T12(H2O)16]·2phen·16H2O [Ln = Sm (2a), Eu (2b), and Gd (2c)], and [Ho8(phen)2Ge12(µ3-O)24T12(H2O)14]·2phen·13H2O (3), have been hydrothermally synthesized from the reactions of bis(carboxyethylgermanium sesquioxide) and Ln2O3 with auxiliary phen chromophores. Compounds 1a and 1b consist of cage clusters [Ln8(phen)2Ge12(µ3-O)24T12(H2O)16] and free H2O molecules, where cage clusters are arranged in a CsCl type, while compounds 2a-2c consist of cage clusters [Ln8(phen)2Ge12(µ3-O)24T12(H2O)16], free phen, and free H2O molecules, where cage clusters are arranged in a NaCl type. Compound 3 consists of the one-dimensional neutral chain [Ho8(phen)2Ge12(µ3-O)24T12(H2O)14]n and free H2O molecules. These compounds provide the first examples of p-f heterometallic [Ge-O-Ln] oxo clusters decorated by phen chromophores. The photoluminescent and magnetic properties of all compounds have been investigated.