Photosensitive Dye Research Articles

Cosensitization of a Tetraethylene Glycol‐Substituted Unsymmetrical Zinc Phthalocyanine Sensitized Solar Cells with D131 Auxiliary Dye Exhibited Enhanced Efficiency

AbstractAn asymmetric zinc phthalocyanine dye (ZnPcT3C), bearing three tetraethylene glycol donor groups and one carboxylic acid anchoring group, was synthesized as a photosensitizer dye for dye‐sensitized solar cells (DSSCs). The tetraethylene glycol (TEG), consisting of four ethoxy units, works as an amphiphilic long‐chain donor group that greatly helped in reducing the molecular aggregation. Carboxylic acid group, on the other hand, an acceptor, together with TEG in ZnPcT3C functions as a ‘push–pullʼ system suitable for DSSCs. Absorption spectra of ZnPcT3C in DMSO showed a strong sharp Q band in the infrared region 600–700 nm with (λmax = 682 nm) and a less intense soret band appeared in the region 300–400 nm with λmax = 340 nm. The zinc phthalocyanine (ZnPcT3C) exhibited molar extinction coefficient (ε) of 72,727 L mol−1cm−1. The emission was observed at λem = 695 nm upon excitation at 650 nm and exhibited a fluorescence decay of 2.82 ns. The ZnPcT3C dye sensitised solar cell (c = 1 mM) exhibited the power conversion efficiency (η) of 3.52% in chloroform in I−/I3 electrolyte under simulated 100% brightness. Cosensitization of ZnPcT3C with another auxiliary dye D131 in 1:1 ratio in a cocktail‐type DSSC attained the power conversion efficiency of twice as high as η = 6.27% in an identical condition. A mixture of D131 (λmax = 470 nm) dye with the ZnPcT3C phthalocyanine harvests sunlight across the visible spectra, enabling DSSCs to attain a large photocurrent and photovoltage, enhancing power conversion efficiency.

Investigation of the impact of internal acceptor and π-linker in 2, 5-di(2-thienyl)pyrrole based organic dye photosensitizer for DSSCs

The effect of π-linkers and internal acceptor group on the optoelectronic characteristics of D-π-A and D-A′-π-A dyes for dye-sensitized solar cells (DSSC) were examined. The DFT was used for estimating geometries and charge transport parameters, and the TD-DFT for calculating electronic excitations of these dyes. HOMO, LUMO, and HOMO-LUMO energy gap were also calculated for appreciating the suitable electron transfer, dye regeneration, and charge injection. For achieving the improved performance of dyes in DSSC, injection driving force (ΔGinj), short circuit current (JSC), the open circuit voltage (VOC), light harvesting efficiency (LHE), dye regeneration energy (ΔGreg), and Power conversion efficiency were also determined. For suitable Power conversion efficiency of the DSSCs, electron affinity (EA), hole and electron extraction potential, Ionization potential (IP), Total density of states, and Electrostatic potential (ESP) were also calculated. The result shows that the internal acceptor and π-linkers affect the photovoltaic parameters and a small variations in the dye architecture increase the efficiency of DSSCs. The dyes containing diphenyl π-linkers showed maximum power conversion efficiency for solar cell.

Rational Design of Facile and Low‐Cost Construction of Carbon‐Based Dye‐Sensitized Solar Cells using Garcinia Mangostana L. as a Photosensitizer

Research on solar cell devices is not only always related to how to obtain high power conversion efficiency (PCE), but also other factors need to be fully considered, such as the cost and their ecofriendliness. In this present research, a low‐cost and ecofriendly dye‐sensitized solar cell (DSSC) is being developed using a graphite‐based nanocomposite and an unusual plant extract (Garcinia mangostana L.) as the dye photosensitizer. A rational design on how to use graphite as a photoanode and counter electrode (CE) in DSSC is carried out by combining the graphite with ZnO and multiwalled carbon nanotube (MWCNT), respectively. It is observed that graphite acts as a matrix for ZnO and MWCNT to make these nanocomposites have very appropriate optoelectronics and catalytic properties compared to the control sample. Therefore, they could serve as an excellent photoanode and CE, respectively. It is also expected that the anthocyanin absorption in Garcinia mangostana L. dye which is found in the visible light range can efficiently absorb photons, thus supporting the enhancement of photovoltaic performance of the DSSC. The generated voltage (V) and current (I) from light irradiation using commercial lamps are higher compared to halogen lamps, indicating that the obtained DSSC has potential as indoor powered devices. It is believed that our study can shed light on the development of DSSC using low‐cost material graphite as the main component for the realization of low‐cost DSSC devices.

Discovering the potential of biomaterial-based mesoporous and magneto-luminescent nanohybrid (Nd-doped Hydroxyapatite/Fe3O4) for cancer theragnosis

Multimodality nanoplatforms play a crucial role in advancing medical interventions by integrating multiple functionalities into a single system. However, issues like intricate production processes and biocompatibility persist. Herein, a facile synthesis of a biomaterial-based mesoporous nanocarrier, HAp:Nd+SPIONs@mSiO2 is reported. The nanohybrid with ∼100 nm average size, comprised of Nd-doped hydroxyapatite (HAp:Nd) nanophosphor, Fe3O4 superparamagnetic iron oxide nanoparticles (SPIONs), and mesoporous silica, exhibiting magneto-luminescent properties. The nanohybrid showed NIR to NIR photoluminescence properties important for deep tissue imaging. The mesoporous nanohybrid was loaded with Indocyanine green (ICG), a photosensitizer and photothermal dye, as a model drug (∼6 μg/mg of nanoparticles) with a high absorption stability retaining >75 % drug until 24 h incubation in pH 6 and 7.4, respectively. Nanoparticles demonstrated dual functionality by generating heat through magnetic and photonic stimulation, as well as producing reactive oxygen species (ROS) upon excitation with 808 nm light. In vitro assays on aggressive triple-negative breast cancer cells (MDA-MB-231) showed the high biocompatibility of nanohybrid with and without ICG, while a significant toxicity was seen after irradiation of NIR light due to ROS production. Noticeably, the nanohybrids also exhibit the ability to monitor temperature changes via Nd3+ associated NIR luminescence. The nanoplatform integrates clinically relevant components like hydroxyapatite, SPIONs, mesoporous silica and ICG, highlighting its potential for translational applications. The developed nanohybrids, with combined NIR-mediated photothermal and photodynamic effects, magnetic photothermal capabilities, and NIR/MR imaging, offer promise in addressing cancer heterogeneity and improving conventional treatments with reduced side effects.

β-Cyclodextrin-Modified Cotton Fabric for Medical and Hospital Applications with Photodynamic Antibacterial Activity Using Methylene Blue

The use of cyclodextrins in textiles for the development of biofunctional fabrics represents an interesting alternative for the advancement of dental, medical, and hospital materials. Cyclodextrins can interact with the chemical groups present in cotton fibers, leading to the formation of a nanostructured surface with specific functional properties, including antibacterial activity. Although there are numerous antibacterial textile finishes, the use of methylene blue as a cyclodextrin host molecule for photodynamic applications in textile materials remains to be investigated. This is because methylene blue is a photosensitive dye capable of generating singlet oxygen (1O2) when illuminated, which inactivates the pathogenic microorganisms that may be present in wounds. The objective of this study was to develop a biofunctionalized and photoactivatable cotton fabric with antimicrobial properties for use in the cosmetic or medical industries. The materials obtained were characterized via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), the determination of cotton fabric functionalization dyeing variables, colorimetry, UV-VIS spectrophotometry, degradation of 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), photodegradation tests, and microbiological analysis. The results showed that the textile was functionalized with β-cyclodextrin, mainly evidenced by the appearance of the band at 1730 cm−1, indicating the formation of the ester group. Thus, when exposed to light, the non-functionalized material showed greater photobleaching, about 60%, compared to the material treated with cyclodextrin. This result was also reflected in the ABDA degradation kinetics, with the treated material showing 592.00% (first phase) and 966.20% (second phase) higher degradation than the untreated sample. Finally, the photodynamic activity was determined based on the antimicrobial properties of the textile, showing a reduction of more than 99% without exposure to light and 100% when exposed to light. It is believed that this study could open avenues for future research and the development of antimicrobial fabrics, as well as demonstrate the efficiency of the treatment with cyclodextrin in relation to photobleaching.

Synthesis, Crystal Structure, and Theoretical Screening of Solvatochromism and Light-Harvesting Performance of Hexamine V-Substituted Lindqvist-Based Photosensitizer for Photovoltaic Solar Cells.

In this paper, we employ density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches to predict the solvatochromism and light-harvesting properties of a newly synthesized hybrid hexamine (HMTA) vanadium-substituted Lindqvist-type (V 2 W 4 ) polyoxometalate (POM), (C7H15N4O)2(C6H13N4)2[V2W4O19]·6H2O, (HMTA-V 2 W 4 ) for application in dye-sensitized solar cells (DSSCs). Single crystal X-ray diffraction (XRD) and noncovalent interaction (NCI) analyses show a 3D-supramolecular packing stabilized by means of hydrogen bonds and van der Waals (vdW) and ionic interactions between highly nucleophilic cage-like HMTA surfactant, lattice water, and electrophilic V 2 W 4 polyanions. Experimental and theoretical UV/vis absorption spectra show large absorption in the visible region, which is strongly solvent polarity dependent. This solvatochromic behavior can be attributed to hydrogen bonding interactions between the V 2 W 4 polyanion and protic solvents. Furthermore, the energy level of semiconductor-like nature of HMTA-V 2 W 4 with high LUMO level matches well with the conduction band (CB) of TiO2, which is beneficial for the photovoltaic device performance. The photovoltaic empirical parameters are theoretically predicted to demonstrate a remarkably high open-circuit voltage (Voc) value (1.805 eV) and a photoelectric conversion efficiency (PCE) value up to 8.7% (FF = 0.88) along with superior light-harvesting efficiency (LHE) (0.7921), and therefore, the studied compound is expected to be a potential candidate as a photosensitizer dye for applications in DSSCs. The aim of this work was to broaden the range of applications of POMs, owing to their low-cost fabrication, leveraging and flourishing optoelectronic properties, and ever-improving efficiency and stability for use in future technology pointed to the development of clean and green renewable energy sources to solve the current energy crisis.

Study of photosensitizer dyes for high-performance dye-sensitized solar cells application: A computational investigation

Dye-sensitized solar cells (DSSCs) offer a promising, cost-effective alternative to conventional photovoltaic systems. Organic sensitizers, capable of capturing a broad spectrum of sunlight, are key components in DSSCs, but their development and testing are often time-consuming and expensive. Quantum chemical calculations, specifically Density Functional Theory (DFT), have emerged as valuable tools to evaluate potential dye candidates, streamlining the design process and reducing costs. This study investigated the molecular structures and photophysical properties of three common dye classes used in high-performance DSSCs: natural pigments, anthocyanidin pigments, and squaraine dyes. Employing DFT and time-dependent DFT (TD-DFT) at the B3LYP/6–31G level, key parameters such as the HOMO-LUMO energy gap, free energy differences for electron injection and dye regeneration, short-circuit current density, total reorganization energy, and open-circuit voltage were analyzed. Additionally, maximum absorption wavelengths and oscillator strength values were calculated. Our findings provide valuable insights into the optical and electrical properties of these natural dyes, aiding DSSC manufacturers in selecting optimal sensitizers. This research highlights the potential of computational methods in accelerating dye development and improving the overall efficiency of DSSC technology.

High energy throughput using photogalvanic solar techniques and environmentally benign chemical system

Solar energy is gradually becoming integrated into households, holding the potential to address energy requirements through technologies like PV cells. Ongoing research is actively exploring diverse methods of harnessing solar power, with Photogalvanic cells emerging as a particularly promising alternative to Photovoltaic cells. The advantage lies in the cost-effectiveness and simplified fabrication, coupled with the capability of power storage. The utilization of the economical Dioctyl sulfosuccinate sodium (DOSS) surfactant, widely employed in industry, has yielded impressive electrical performance. The present investigation presents a reliable photogalvanic system composed of the photosensitizer dye Quinoline Yellow, the reductant Cellobiose, and the surfactant Dioctyl sulfosuccinate sodium (DOSS), all in a highly alkaline solution with platinum and graphite electrodes. The platinum electrode employed is notably small, boasting a surface area of 0.03 cm2, which enhances the diffusion characteristics of the dye molecules, it is contributing to an enhanced electrical performance of the photogalvanic cell. The resulting photogalvanic cell demonstrates superior electrical performance, featuring a maximum potential of 870 mV, a maximum current of 8000 µA, power at PowerPoint of 695 µW, a fill factor of 0.11, and a conversion efficiency of 13.78 %. Spectrophotometric analysis has confirmed the stability of the dye within the electrolyte solution. Additionally, conductometric analysis has revealed that the surfactant Dioctyl sulfosuccinate sodium (DOSS) enhances the electrical conductivity of the electrolyte solution.

Optimization of the structural, optical, and photovoltaic characteristics of a novel ruthenium(III) complex as a photosensitizer for solar cells

A novel ruthenium(III) complex, [Ru(DAP)2(H2O)2]Cl3 (where DAP = 5,6-Diamino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione), was synthesized for potential application as a photosensitizer dye in solar cell. The ruthenium complex was made and precipitated as violet crystals by reaction of K2[RuCl5H2O] with the ligand DAP, in an aqueous ethanol (1:1; v/v)). Elemental analysis, magnetic, thermal, X-ray diffraction, electron scanning microscope and spectroscopic techniques were used for physico-chemical characterizations. Additionally, the electrochemical properties were studied by cyclic voltammetry and voltammogram showed different peaks with different oxidation potentials confirming an extraordinary electrochemical property for the complex. The fabrication of nanostructured films of ruthenium(III) complex was achieved through the thermal evaporation technique, and from which optical and electrical characterizations were studied and interpreted. A solar cell hybridizing organic and inorganic materials, incorporating a ruthenium(III) complex and silicon, was fabricated. The current-voltage characteristic of this cell was measured, and from which the photovoltaic parameters were estimated. The solar cell exhibits a filling factor of 0.40 and an efficiency of 3.58 %.

Photoimmunotherapy of Prostate Cancer With Antibody and Fab Fragments Targeting the Prostate Specific Membrane Antigen.

The standard treatment for localized prostate cancer involves surgical removal of the prostate with curative intent. However, when tumor cells persist in the operation site, there is high risk of local recurrence and tumor spread, leading to stressful follow-up treatments, impaired quality of life, and reduced overall survival. This study examined photoimmunotherapy (PIT) as a new treatment option for prostate cancer cells. We generated conjugates consisting of either a humanized antibody or Fab fragments thereof targeting the prostate specific membrane antigen (PSMA), along with our silicon phthalocyanine photosensitizer dye WB692-CB1. PSMA-expressing prostate cancer cells were incubated with the antibody dye or Fab dye conjugates and cell binding was measured using flow cytometry. Cells were irradiated with varying doses of red light for dye activation, and cytotoxicity was determined by erythrosin B staining and subsequent analysis using a Neubauer counting chamber. Specific cytotoxicity was induced with the antibody dye conjugate in the prostate cancer cells in a light dose-dependent manner. Treatment of the cells with the Fab dye conjugate resulted in lower cytotoxicity, which could be attributed to a reduced binding affinity and a reduced dye uptake of the Fab fragment. Our new antibody dye and Fab dye conjugates offer potential for future intraoperative PIT in patients with localized prostate cancer, with the aim to ensure complete removal of tumor cells from the surgical area, to avoid local recurrence, and to improve clinical outcome.

Graphite counter electrode modified Tropaeolin‐O photo‐sensitized photogalvanic cells for solar power and storage

AbstractAn optimization, photo‐stability, and hysteresis property of the Graphite counter electrode‐modified Tropaeolin‐O (TPO) photo‐sensitized photogalvanic (PG) cells has been investigated. A complex H‐shaped cell design, a costly and delicate saturated calomel electrode (counter electrode), and a heavy sensitizer molecule (dye having high molecular weight, low diffusivity, and low photo‐stability) have been exploited for fabricating most of the PG cells so far. All these factors are not suitable for the fabrication of durable and cheap PG cells. Therefore, in the present study, the highly conductive/catalytically active robust graphite electrode with TPO dye photosensitizer (having a low molecular weight, higher diffusivity, and higher photo‐stability) has been exploited with diffusion‐friendly low cost and a simple transparent cylindrical glass tube. The cheap and robust graphite counter electrode has been exploited for optimization and long‐term study of the TPO photo‐sensitized PG cells. The observed electrical output is potential 676 mV, current 2000 µA, and power 340.0 μW. The power, current, and efficiency, have been found quite independent of the illumination window size. The potential and current have been observed to be quite stable over a long time during illumination, and the same has been supported by the hysteresis study.

A Systemic Review on Photodynamic Therapy: Emerging Technology with Healing Process

Abstract: Photodynamic therapy (PDT) is a non-invasive treatment of cancer patients who take a photosensitizer and expose their tumours to light after administering it topically or intravenously. Understanding apoptosis under oxidative conditions makes PDT a more effective treatment. Tissue oxygen, tumour-selective photosensitizer dyes, and customised lighting are needed to create fatal reactive oxygen species (ROS) in cancer. PDT has decreased morbidity and improved survival and status of life when used in combination with other treatments, especially in early-stage malignant tumours. Using interstitial light delivery, PDT can cure large, hidden tumours that would otherwise necessitate extensive surgery. This overview describes the foundational historical work that has shaped the technique since the early 1900s. PDT's efficacy is also increased by innovative photosensitizers and tweaks that increase tumour selectivity. Adverse effects and treatment during therapy, as well as innovative PDT-based applications, are explored in this review. Finally, PDT research gaps and clinical trials have been identified as potential issues.

Development of natural dye photosensitizers for dye-sensitized solar cells: a review.

Dye-sensitized solar cell (DSSC) is a photovoltaic device that can be produced from natural source pigments or natural dyes. The selection of natural dyes for DSSC application is currently under research. The utilization of natural dye materials that are easy to obtain, cost-effective, and non-toxic can reduce waste during DSSC fabrication. Natural dyes can be extracted from plants through extraction and chromatography methods. The suitability and viability of utilizing natural dyes as photosensitizers in DSSCs can be predicted using appropriate software simulation by varying related parameters to produce high power conversion efficiency. In this context, the purpose of the review is to highlight the evolution of performance improvement in the development of DSSCs with consideration of natural dye extraction and software simulation. This review also focuses on the results of extracting natural dyes from herbal ingredients, which are still very limited in information, and several parts of herbal plants that can be used as natural dye sources in the future of solid-state DSSCs have been identified. Based on the results of this review, the highest efficiency was obtained for the DSSC that used chlorophyll pigments as natural dyes using Peltophorum pterocarpum leaves with 6.07%, followed by anthocyanin pigments as natural dyes using raspberries (black) fruits with 1.5%, flavonoid pigments as natural dyes using Curcuma longa herbs with 0.64%, and flavonoid pigments as natural dyes using Indigofera tinctoria flowers with 0.46%.

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens.

Antimicrobial resistance has emerged as a global threat to the treatment of infectious diseases. Antibacterial photodynamic therapy (aPDT) is a promising alternative approach and is highly suitable for the treatment of cutaneous bacterial infections through topical applications. aPDT relies on light-responsive compounds called photosensitizer (PS) dyes, which generate reactive oxygen species (ROS) when induced by light, thereby killing bacterial cells. Despite several previous studies in this area, the molecular details of targeting and cell death mediated by PS dyes are poorly understood. In this study, we further investigate the antibacterial properties of two water-soluble Sn(IV) tetrapyridylporphyrins that were quaternized with methyl and hexyl groups (1 and 2). In this follow-up study, we demonstrate that Sn(IV)-porphyrins can be photoexcited by blue light (a 427 nm LED) and exhibit various levels of bactericidal activity against both Gram-(+) and Gram-(-) strains of bacteria. Using localization studies through fluorescence microscopy, we show that 2 targets the bacterial membrane more effectively than 1 and exhibits comparatively higher aPDT activity. Using multiple fluorescence reporters, we demonstrate that photoactivation of 1 and 2 results in extensive collateral damage to the bacterial cells including DNA cleavage, membrane damage, and delocalization of central systems necessary for bacterial growth and division. In summary, this investigation provides deep insights into the mechanism of bacterial killing mediated by the Sn(IV)-porphyrins. Moreover, our approach offers a new method for evaluating the activity of PS, which may inspire the discovery of new PS with enhanced aPDT activity.

Light Management Investigation of Transparent DSSC based on Ln3+ ion doped BaO-ZnF2-B2O3-TeO2 Glass (Ln3+ = Dy3+/Sm37Eu3+) as UV Down-conversion Material

Solar irradiance to electrical energy conversion could be achieved via photoelectric effect using solar cells device. However, not all solar wavelengths could be captured and converted by the active layer of solar cell. The absorption limitation associated with the bandgap energy of solar cell active layer in the ultraviolet region (high photon energy) and infrared region (low photon energy) leads to 70% energy loss. Introducing a material that can convert higher photon energy to lower photon energy that is suitable with the bandgap energy of the solar cell provides a solution to this problem. In the present work, glass materials based on BaO, ZnF2, B2O3, TeO2, and Ln2O3 (Ln2O3 = Dy2O3, Sm2O3, and Eu2O3) were developed using conventional melt and quenching technique and applied as down-conversion (DC) element in dye-sensitized solar cell (DSSC). The absorption spectra of Z907 as dye photosensitizer was measured as well as the absorption spectra of DC glass. The DC glass emission spectra were also investigated to know the compatibility between the absorption of solar cell and the emission band of the DC glass. The current-voltage of the DSSC was measured while placing the DC glass on top of the solar cell device. The electrical parameters, such as power conversion efficiency, fill factor, short-circuit current, and open-circuit voltage, were then determined to analyze the effect of DC glass application on the performance of DSSC. DC glass with 1.5Eu produced an efficiency of 2.03%, showing the best result among other lanthanide ions.

Using single atom substitution strategy for constructing a novel Se-substituted hemicyanine dye with hydroxyl group as an ideal activatable photosensitizer dye scaffold

Photodynamic therapy (PDT) is an effective method to treat diseases, especially for tumor treatment, with remarkable characteristics including good therapeutic results and low drug resistance, which has attracted the attention of researchers. The performances of photosensitizer dye largely determine the tumor treatment results. However, most of the reported photosensitive dyes belong to the “always-on” photosensitive property, which cannot avoid the photodamage caused to normal tissues during tumor PDT. By contrast, activatable photosensitizers possess the desirable characteristic of controllable phototoxicity, ensuring tumor safety treatment. Until now, ideal photosensitizer dye scaffold is still lacking. Therefore, constructing a universal photosensitive dye scaffold is a vital issue to be solved urgently. In this work, inspired by the single atom substitution strategy, the oxygen atom in classical hemicyanine dye has been replaced by selenium (Se) atom to obtain a novel Se-substituted hemicyanine dye with hydroxy group, HCySe-OH, as a novel dye platform for constructing activatable photosensitizers. We found that HCySe-OH had high singlet oxygen (1O2) generation ability and longer absorption and emission in contrast to the classical O-substituted hemicyanine, endowing its better biomedical application. Additionally, HCySe-OH was successfully utilized to kill cancer cells and bacteria under 760 nm laser irradiation. More importantly, we believe that numerous smart activatable photosensitizers will be developed based on this platform, HCySe-OH.

Design of 1,8‐Naphthalimide‐Based Fluorescent Functional Molecules for Biological Application: A Review

Abstract1,8‐Naphthalimide fluorophore, as the classical skeleton for fluorescent functional molecules, has gained much attention in the chemistry and biomedical field due to its excellent fluorescent properties, photostability, and structural flexibility. The rational design of the substituents on the C‐4 position and N‐position of 1,8‐naphthalimide chromophore can provide specific functions for the molecules, such as fluorescence sensing, energy‐trapping, and targeting. This review presents the design progress of 1,8‐naphthalimide‐based fluorescence sensors for metal ions and biological molecules, and 1,8‐naphthalimide‐functionalized photosensitive dyes in the biological field over the past years. We summarize the general fluorescent molecular design strategies, recent developments of 1,8‐naphthalimide in innovative photosensitizers, and the challenges, wishing to promote new ideas in developing smart and functional molecules from 1,8‐naphthalimide derivatives.

Tumor oxygen microenvironment-tailored electron transfer-type photosensitizers for precise cancer therapy.

The oxygen level in a tumor typically exhibits complex characteristics, ranging from mild hypoxia to moderate and even severe hypoxia. This poses significant challenges for the efficacy of photodynamic therapy, where oxygen is an essential element. Herein, we propose a novel therapeutic strategy and develop a series of lipid droplet-targeting photosensitive dyes (Ser-TPAs), i.e., in situ synergistic activation of two different electron transfer-type reactions. Based on this strategy, Ser-TPAs can synergistically generate O2˙- and nitrogen radicals regardless of the oxygen content, which results in a sustained high concentration of strongly oxidizing substances in the lipid droplets of cancer cells. As such, Ser-TPAs exhibited inhibitory activity against tumor growth in vivo, resulting in a significant reduction in tumor volume (V experimental group : V control group ≈ 0.07). This strategy offers a conceptual framework for the design of innovative photosensitive dyes that are suitable for cancer therapy in complex oxygen environments.

Betanin dye extracted from ayrampo (Opuntia soehrensii) seeds to develop dye-sensitized solar cells.

Pigments extracted from ayrampo seeds of the Peruvian-native prickly pear (Opuntia soehrensii) were used in dye-sensitized solar cells with promising efficiencies. The performance of the solar cells was then improved via the addition of citric acid to stabilise the photosensitive dye, and an efficiency of 1.41% was achieved with current output remaining stable after 7 days. Upon testing in low-light conditions, the solar conversion efficiency of devices increased to 4%. This paper not only highlights the potential of natural sensitizers in DSSCs but also shows that simple extraction and gentle handling methods can contribute to the device performance.

Dynamic circularly polarized luminescence regulated by photosensitive achiral dichroic dyes in cholesteric liquid crystal medium

Herein, we have developed photosensitive ternary cholesteric liquid crystals (T-N*-LCs) by doping achiral dichroic dye PBCy and chiral inducer R/S-1 in 5CB. Under alternating UV and visible light treatment, different isomers of PBCy exhibited varying order parameter (SF) values in 5CB, resulting in T-N*-LCs showing a dynamic CPL switch from strong (SF = 0.18. glum = +0.45/-0.48) to weak (SF = 0.10. glum = +0.23/-0.21). This alteration allows for the regulation of the CPL signal of T-N*-LCs, while keeping the helical pitch and chiral spin of T-N*-LCs unchanged. Based on these phototunable CPL and fluorescence behaviors, a geminate mode device carrying different information could be prepared.