Regulation of excitation energy transfer in Sb-alloyed Cs_(4)MnBi_(2)Cl_(12) perovskites for efficient CO_(2) photoreduction to CO and water oxidation toward H_(2)O_(2)

Lead(Pb)-free halide perovskites have recently attracted increasing attention as potential catalysts for CO_(2) photoreduction to CO due to their potential to capture solar energy and drive catalytic reaction.However,issues of the poor charge transfer still remain one of the main obstacles limiting their performance due to the overwhelming radiative and nonradiative charge-carrier recombination losses.Herein,Pb-free Sb-alloyed all-inorganic quadruple perovskite Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12)(0≤x≤1)is synthesized as efficient photocatalyst.By Sb alloying,the undesired relaxation of photogenerated electrons from conduction band to emission centers of[MnCl6]^(4-)is greatly suppressed,resulting in a weakened PL emission and enhanced charge transfer for photocatalyst.The ensuing Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12) photocatalyst accomplishes efficient conversion of CO_(2)into CO,accompanied by a surprising production of H_(2)O_(2),a high valueadded product associated with water oxidation.By optimizing Sb^(3+) concentration,a high CO evolution rate of 35.1μmol g^(-1)h^(-1)is achieved,superior to most other Pb and Pb-free halide perovskites.Our findings provide new insights into the mixed-cation alloying strategies for improved photocatalytic performance of Pb-free perovskites and shed light on the rational design of robust band structure toward efficient energy transfer.

Photo-induced carbon dioxide reduction on hexagonal tungsten oxide via an oxygen vacancies-involved process

Although converting the greenhouse gasses carbon dioxide(CO_(2))into solar fuels is regarded as a convenient means of solar energy storage,the intrinsic mechanism on how the high chemical inertness linear CO_(2)molecules is activated and converted on a semiconductor oxide is still elusive.Herein,by creating the oxygen vacancies on the typical hexagonal tungsten oxide(WO3),we realize the continuous photoinduced CO_(2)reduction to selectively produce CO under light irradiation,which was verified by isotope labeling experiment.Detailed oxygen vacancies evolution investigation indicates that light irradiation can simultaneously induce the in-situ formation of oxygen vacancies on hexagonal WO3,and the oxygen vacancies promote the adsorption and activation of CO_(2)molecules,leading to the CO_(2)reduction to CO on the hexagonal WO3via an oxygen vacancies-involved process.Besides,the existence of water further promotes the formation of CO_(2)reduction intermediate,further promote the CO_(2)photoreduction.Our work provides insight on the mechanism for converting CO_(2)into CO under light irradiation.

ESIPT-based AIE luminogens:Design strategies,applications,and mechanisms

In this review,we present a systematic and comprehensive summary of the recent development and applications of excited-state intramolecular proton transfer-based(ESIPT-based)aggregation-induced emission luminogens(AIEgens),a type of promising materials that inherit the advantages of ESIPT and AIE,such as large Stokes shift,excellent photostability,and low self-quenching.We first summarize the backbones that have been used to construct the ESIPT-based AIEgens and classify the constructed ones based on the relation between ESIPT and AIE unit.According to the sensing mechanisms and design strategies,we have reviewed the applications of ESIPT-based AIEgens in bioimaging,drug delivery systems,organic lightemitting diodes,photo-patterning,liquid crystal,and the detection of metal cations,anions,small molecules,biothiols,biological enzymes,latent fingerprinting,and so on.We have also reviewed the recent advances in the development of new theoretical methods for investigating molecular photochemistry in crystals and their applications in ESIPT-based AIEgens.We discussed the remaining challenges in this field and the issues that need to be addressed.We anticipate that this review can provide a comprehensive picture of the current condition of research in this field,and promote researchers to make more efforts to develop novel ESIPT-based AIEgens with new applications.

Se-sensitized NIR hot band absorption photosensitizer for anti-Stokes excitation deep photodynamic therapy

Conventional anti-Stokes materials-involved deep photodynamic therapy(dPDT)requires much high-intensity irradiance due to low photosensitization efficiency.Herein,we proposed a"booster effector"approach to construct highly efficient hot band absorption phototherapeutics for low/biosafety power anti-Stokes light-triggered d PDT.Se,as"booster effector",was introduced into hot band absorption luminophores(HBAs),which not only significantly facilitated intersystem crossing,but also simultaneously enhanced hot band excitation efficiency atν808,as a result successfully enabling excellent photogenerated singlet oxygen capability of HBAs under ultra-low power anti-Stokes excitation(10 mW cm^(-2)in vitro).As far as we know,such low laser power-initiated photosensitization activity has never been reported in the existing anti-Stokes material systems.Importantly,FUC-Se ME can self-assemble into uniform nanospheres in water,greatly boosting cellular uptake(>25-fold larger than FUC-Se),and achieve superior cancer-killing effect(808 nm,10 mW cm^(-2),5 min,the half-maximal inhibitory concentration IC50=1.36μM).After further PEGylation with folate-attached polymer,the resultant FUC-Se ME@FA can effectively enrich at the tumor(signal-to-background ratio,10).Under safety irradiation(330 mW cm^(-2)),FUC-Se ME@FA effectively inhibits deep-seated tumor progression(the tumor growth inhibition rate,84%).This work provides a successful paradigm,possibly being more clinically beneficial than conventional anti-Stokes materials.

The unexpected“butterfly effect”of Pt-coordinated cyanine self-assembly for enhanced tumor photothermal therapy

J-aggregates of cyanine have shown great merits in tumor photothermal therapy(PTT)due to their distinct redshift absorption as well as superior photothermal conversion efficiency(PCE).However,due to the complexity of intermolecular interactions,especially the impact of steric hindrance on aggregation,exploring effective strategies to regulate the aggregation modes of organic materials remains challenging.Herein,steric hindrance-regulated J-aggregation of near-infrared(NIR)cyanine was reported based on Pt-coordinated cyanine self-assembly with unexpected“butterfly effect”.Two Pt-coordinated cyanine dimers CyR-Pt(R=Me and Et)were synthesized and spontaneously self-assembled into aggregates in aqueous solution.CyEt-Pt aggregates were loose and amorphous stacking.By replacing ethyl with methyl to reduce steric hindrance,a tiny change resulted in the generation of tightly stacked cyanine J-aggregates(thickness less than 3 nm)observed in CyMe-Pt self-assembly.Significantly,this unexpected“butterfly effect”enabled CyMe-Pt J-aggregates to effectively inhibit reactive oxygen species and greatly improve its photostability.Besides,CyMe-Pt J-aggregates with NIR-II absorption exhibited outstanding photothermal stability and higher PCE(η=37%)than CyEt-Pt disordered aggregates(η=20%).Evident tumor suppression performance of CyMe-Pt J-aggregates was validated under 980 nm laser irradiation,demonstrating its great potential in tumor PTT.