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Controlling the interplay between relaxation and charge/energy transfer processes in the excited states of photocatalysts is crucial for the performance of artificial photosynthesis. Metal‐to‐ligand charge‐transfer triplet states (3MLCT*) of ruthenium(II) complexes are broadly implemented for photocatalysis, but an effective means of managing the triplets for enhanced photocatalysis has been lacking. Herein, We proposed a strategy to considerably prolong the triplet excited‐state lifetime by decorating a ruthenium(II) phosphine complex (RuP‐1) with pendent polyaromatic hydrocarbons (PAHs). Systematic studies demonstrate that in RuP‐4 decorated with anthracene, sub‐picosecond electron transfer from anthracene to 3MLCT* leads to a charge‐separated state that can mediate the formation of the intra‐ligand triplet state (3IL) of anthracene, resulting in an exceptionally long excited‐state up to several milliseconds. This triplet management strategy enables impressive photocatalytic reduction of CO2 to CO with a turnover number (TON) of 404, an optimized quantum yield of 43 % and 100 % selectivity, which is the highest reported performance for mononuclear photocatalysts without additional photosensitizers. RuP‐4 also catalyzes photochemical hydrogen generation under argon. This work opens up an avenue for regulating the excited‐state charge/energy flow for the development of long‐lived 3IL multi‐functional mononuclear photocatalysts to boost artificial photosynthesis. [ABSTRACT FROM AUTHOR]

Decreasing perovskite nanocrystal size increases radiative recombination due to the quantum confinement effect, but also increases the Auger recombination rate which leads to carrier imbalance in the emitting layers of electroluminescent devices. Here, we overcome this trade‐off by increasing the exciton effective mass without affecting the size, which is realized through the trace Cd2+ doping of formamidinium lead bromide perovskite nanocrystals. We observe an ~2.7 times increase in the exciton binding energy benefiting from a slight distortion of the [BX6]4− octahedra caused by doping in the case of that the Auger recombination rate is almost unchanged. As a result, bright color‐saturated green emitting perovskite nanocrystals with a photoluminescence quantum yield of 96 % are obtained. Cd2+ doping also shifts up the energy levels of the nanocrystals, relative to the Fermi level so that heavily n‐doped emitters convert into only slightly n‐doped ones; this boosts the charge injection efficiency of the corresponding light‐emitting diodes. The light‐emitting devices based on those nanocrystals reached a high external quantum efficiency of 29.4 % corresponding to a current efficiency of 123 cd A−1, and showed dramatically improved device lifetime, with a narrow bandwidth of 22 nm and Commission Internationale de I'Eclairage coordinates of (0.20, 0.76) for color‐saturated green emission for the electroluminescence peak centered at 534 nm, thus being fully compliant with the latest standard for wide color gamut displays. [ABSTRACT FROM AUTHOR]

All‐inorganic metal halides with afterglow emission have attracted increasing attention due to their significantly longer afterglow duration and higher stability compared to their organic–inorganic hybrid counterparts. However, their afterglow colors have not yet reached the blue spectral region. Here, we report all‐inorganic copper‐doped Rb2AgBr3 single crystals with ultralong blue afterglow (>300 s) by modulating defect states through doping engineering. The introduction of copper(I) ions into Rb2AgBr3 facilitates the formation of bromine vacancies, thus increasing the density of trap states available for charge storage and enabling bright, persistent emission after ceasing the excitation. Moreover, cascade energy transfer between distinct emissive centers in the crystals results in ultra‐broadband photoluminescence, not only covering the whole white light with near‐unity quantum yield but also extending into the near‐infrared region. This 'cocktail' of exotic light‐emission properties, in conjunction with the excellent stability of copper‐doped Rb2AgBr3 crystals, allowed us to demonstrate their implementation to solid‐state lighting, night vision, and intelligent anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Colloidal semiconductor nanoplatelets (NPLs) have emerged as low‐cost and free‐standing alternates of traditional quantum wells. The giant heavy‐ and light‐hole splitting in NPLs allows for efficient optical spin injection. However, the electron spin lifetimes for prototypical CdSe NPLs are within a few picoseconds, likely limited by strong electron‐hole exchange in these quantum‐ and dielectric‐confined materials. Here how this hurdle can be overcome with engineered NPL‐heterostructures is demonstrated. By constructing type‐I CdSe/ZnS core/shell NPLs, dielectric screening inside the core is strongly enhanced, prolonging the electron spin polarization time (τesp) to over 30 ps (or 60 ps electron spin‐flip time). Alternatively, by growing type‐II CdSe/CdTe core/crown NPLs to spatially separate electron and hole wavefunctions, the electron‐hole exchange is strongly suppressed, resulting in τesp as long as 300 ps at room temperature. This study not only exemplifies how the well‐established synthetic chemistry of colloidal heterostructures can aid in spin dynamics control but also establishes the feasibility of room‐temperature coherent spin manipulation in colloidal NPLs. [ABSTRACT FROM AUTHOR]

Most of current metal halide materials, including all inorganic and organic–inorganic hybrids, are crystalline materials with poor workability and plasticity that limit their application scope. Here, we develop a novel class of materials termed polymeric metal halides (PMHs) through introducing polycations into antimony‐based metal halide materials as A‐site cations. A series of PMHs with orange‐yellow broadband emission and large Stokes shift originating from inorganic self‐trapped excitons are successfully prepared, which meanwhile exhibit the excellent processability and formability of polymers. The versatility of these PMHs is manifested as the broad choices of polycations, the ready extension to manganese‐ and copper‐based halides, and the tolerance to molar ratios between polycations and metal halides in the formation of PMHs. The merger of polymer chemistry and inorganic chemistry thus provides a novel generic platform for the development of metal halide functional materials. [ABSTRACT FROM AUTHOR]

The electronic structure of halide perovskites is central to their carrier dynamics, enabling the excellent optoelectronic performance. However, the experimentally resolved transient absorption spectra exhibit large discrepancies from the commonly computed electronic structure by density functional theory. Using pseudocubic CsPbI3 as a prototype example, here, it is unveiled with both ab initio molecular dynamics simulations and transmission electron microscopy that there exists pronounced dynamical lattice distortion in the form of disordered instantaneous octahedral tilting. Rigorous first‐principles calculations reveal that the lattice distortion substantially alters the electronic band structure through renormalizing the band dispersions and the interband transition energies. Most notably, the electron and hole effective masses increase by 65% and 88%, respectively; the transition energy between the two highest valence bands decreases by about one half, agreeing remarkably well with supercontinuum transient‐absorption measurements. This study further demonstrates how the resulting electronic structure modulates various aspects of the carrier dynamics such as carrier transport, hot‐carrier relaxation, Auger recombination, and carrier multiplication in halide perovskites. The insights provide a pathway to engineer carrier transport and relaxation via lattice distortion, enabling the promise to achieve ultrahigh‐efficiency photovoltaic devices. [ABSTRACT FROM AUTHOR]

It is known that ribonucleotide reductase M2 (RRM2) could be induced by hepatitis B virus (HBV) via DNA damage response. However, whether RRM2 is a potential biomarker for diagnosing and monitoring liver fibrosis in chronic hepatitis B (CHB) patients is still unclear. In this study, CHB patients from GSE84044 (a transcriptome data from GEO data set) were downloaded and RRM2 was selected as a hub gene. Interestingly, a positive correlation was found between serum RRM2 and liver fibrosis stage. The similar results were found in CHB patients with normal alanine aminotransferase (ALT). Notably, RRM2 could effectively differentiate preliminary fibrosis from advanced fibrosis in CHB patients with/without normal ALT. In addition, RRM2 had a better performance in diagnosing liver fibrosis than two commonly used noninvasive methods (aspartate aminotransferase‐to‐platelet ratio index and fibrosis index based on the four factors), two classic fibrotic biomarkers (hyaluronic acid and type IV collagen) as well as Mac‐2 binding protein glycosylation isomer, a known serum fibrosis marker. Moreover, CHB patients with high RRM2, who were associated with advanced fibrosis, had higher expressions of immune checkpoints. Overall, serum RRM2 may be a promising biomarker for diagnosing and monitoring liver fibrosis in CHB patients. [ABSTRACT FROM AUTHOR]

Epitaxial heterostructures of colloidal lead halide perovskite nanocrystals (NCs) with other semiconductors, especially the technologically important metal chalcogenides, can offer an unprecedented level of control in wavefunction design and exciton/charge carrier engineering. These NC heterostructures are ideal material platforms for efficient optoelectronics and other applications. Existing methods, however, can only yield heterostructures with random connections and distributions of the two components. The lack of epitaxial relation and uniform geometry hinders the structure–function correlation and impedes the electronic coupling at the heterointerface. This work reports the synthesis of uniform, epitaxially grown CsPbBr3/CdS Janus NC heterostructures with ultrafast charge separation across the electronically coupled interface. Each Janus NC contains a CdS domain that grows exclusively on a single {220} facet of CsPbBr3 NCs. Varying reaction parameters allows for precise control in the sizes of each domain and readily modulates the optical properties of Janus NCs. Transient absorption measurements and modeling results reveal a type II band alignment, where photoexcited electrons rapidly transfer (within ≈9 picoseconds) from CsPbBr3 to CdS. The promoted charge separation and extraction in epitaxial Janus NCs leads to photoconductors with drastically improved (approximately three orders of magnitude) responsivity and detectivity, which is promising for ultrasensitive photodetection. [ABSTRACT FROM AUTHOR]

As an analogue to thermally activated delayed fluorescence (TADF) of organic molecules, thermally activated delayed photoluminescence (TADPL) observed in molecule‐functionalized semiconductor nanocrystals represents an exotic mechanism to harvest energy from dark molecular triplets and to obtain controllable, long‐lived PL from nanocrystals. The reported TADPL systems have successfully covered the visible spectrum. However, TADF molecules already emit very efficiently in the visible, diminishing the technological impact of the less‐efficient nanocrystal‐molecule TADPL. Here we report bright, near‐infrared TADPL in lead‐free CuInSe2 nanocrystals functionalized with carboxylated tetracene ligands, which results from efficient triplet energy transfer from photoexcited nanocrystals to ligands, followed with thermally activated reverse energy transfer from ligand triplets back to nanocrystals. This strategy prolonged the nanocrystal exciton lifetime from 100 ns to 60 μs at room temperature. [ABSTRACT FROM AUTHOR]

Self‐assembly of nanocrystals into controlled structures while uncompromising their properties is one of the key steps in optoelectronic device fabrication. Herein, zigzag CsPbBr3 perovskite nanocrystals are demonstrated with a precise number of components with nanocube morphology, these can be successfully obtained through a dipole‐induced self‐assembly process. The addition of a trace amount of deionized water facilitates the transfer from CsPbBr3 nanocubes to intermediates of CsPb2Br5 and Cs3In2Br9, which then fastly release reaction monomers leading to further homogenous nucleation of CsPbBr3 nanocubes, followed by the formation of zigzag CsPbBr3 nanocrystals through a dipole‐induced self‐assembly process. Dipole moment along <110> axis is found to be the driving force for the assembly of nanocubes into zigzag nanocrystals. The zigzag CsPbBr3 nanocrystals exhibit desirable optical properties comparable to their nanocube counterparts and offer advantages for amplified spontaneous emission and lasing applications with low pump thresholds of 3.1 and 6.02 µJ cm−2, respectively. This study not only develops a strategy for producing highly controlled zigzag perovskite nanocrystals and provides insights on the dipole‐induced self‐assembly mechanisms, but also opens an avenue for their application in lasing. [ABSTRACT FROM AUTHOR]

Synthetic fluorescent protein chromophores have been reported for their singlet state fluorescence properties and applications in bioimaging, but rarely for the triplet state chemistries. Herein, we enabled their photo‐sensitizing and photo‐crosslinking properties through rational modulations. Extension of molecular conjugation and introduction of heavy atoms promoted the generation of reactive oxygen species. Unlike other photosensitizers, these chromophores selectively photo‐crosslinked aggregated proteins and uncovered the interactome profiles. We also exemplified their general applications in chromophore‐assisted light inactivation, photodynamic therapy and photo induced polymerization. Theoretical calculation, pathway analysis and transient absorption spectroscopy provided mechanistic insights for this triplet state chemistry. Overall, this work expands the function and application of synthetic fluorescent protein chromophores by enabling their triplet excited state properties. [ABSTRACT FROM AUTHOR]

It is well known that charge separation is crucial for efficient photocatalytic solar conversion. Although some covalent‐organic frameworks (COFs) exhibit visible‐light harvest, the large exciton binding energies reduce their photocatalytic efficiencies. Herein, we developed a novel method to post‐treat the olefin‐linked COFs with end‐capping polycyclic aromatic hydrocarbons (PAHs) for spontaneous charge separation. Interestingly, a type‐II heterostructure is constructed in our perylene‐modified COFs which displays drastically enhanced performance for photocatalytic CO2 reduction, with an efficiency of 8‐fold higher than that of unmodified COF. A combination of electrochemical, steady‐state, and time‐resolved spectroscopic measurements indicates that such drastically enhanced performance should be attributed to photoinduced spontaneous charge separation in the heterostructure. These results illustrate the feasibility of engineering the charge‐separation properties of crystalline porous frameworks at a molecular level for artificial photosynthesis. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs) can photocatalyze diverse organic reactions. However, reported QD‐photocatalysts often contain highly‐toxic elements Cd or Pb, and have not surpassed prototypical transition‐metal complexes in terms of their photoredox power or excited‐state energy. Here we report low‐toxicity ZnSe/ZnS core/shell QDs as potent visible photocatalysts to drive challenging organic transformations. To overcome the limitation of short excited‐state lifetime of the QDs, we functionalize their surfaces with benzophenone ligands which can rapidly extract electrons from photoexcited QDs and sustain long‐lived charge‐separated states. The benzophenone anions function as potent electron relay to drive dehalogenation of aryl chlorides and additive‐free polymerization of acrylates. Alternatively, the QDs are functionalized with biphenyl ligands to store energy in long‐lived, energetic triplets, enabling [2+2] homo‐cycloaddition of styrene and cycloaddition of carbonyls with alkenes. [ABSTRACT FROM AUTHOR]

The luminescence thermal quenching (LTQ) behavior is one of the detrimental effects which result in poor stability and hinder the practical applications of luminescent nanocrystals (NCs) severely. Suppressing the LTQ effect is fundamentally important, especially for the recent rising star lead halide perovskite NCs while related investigations are rare. Herein, taking CsPbBr3 NCs with high photoluminescence quantum yield (PLQY) as examples, a surface anchoring mechanism is proposed and the LTQ effect is successfully overcome. By introducing hybrid ligand system with large binding effect and steric hindrance, ligand desorption induces irreversible LTQ effect and the formation of surface atom vibration related transient traps is suppressed. As a result, 96.3% and 75.6% of the initial PL intensity are maintained up to 378 and 423 K, respectively, which are even superior to conventional core–shell NCs. Notably, after being treated under 333 K for 15 days, a PL intensity remnant of >88.4% is achieved. Such anti‐LTQ mechanism is also extended to blue perovskite NCs. Temperature‐tolerant stimulated emission and high temperature lasing phenomenon are fulfilled with considerable thermal stability. This work provides a new mechanism which can possibly help to solve the bottleneck toward practical luminescence applications for perovskite nanostructures. [ABSTRACT FROM AUTHOR]

A relatively new addition to the application portfolio of lead halide perovskites is to photosensitize molecular triplets for a variety of photochemical applications. Here we report visible‐light‐driven isomerization and cycloaddition of organic molecules sensitized by spectrally‐tunable perovskite nanocrystals. We first demonstrate with stilbene as the substrate molecule that photoisomerization can proceed efficiently and rapidly by either directly grafting carboxylated stilbene onto nanocrystal surfaces or using triplet–acceptor ligands as the energy relay. The relay approach is more generally applicable as it does not require anchoring‐group functionalization of substrate molecules, allowing us to facilely extend it to isomerization of a series of substituted stilbene molecules and ring‐closing isomerization of diarylethene, as well as intermolecular [2+2] cycloaddition of acenaphthylene. This study opens an avenue of energy‐transfer photocatalysis using perovskite nanocrystals. [ABSTRACT FROM AUTHOR]

Graphene with linear energy dispersion and weak electron–phonon interaction is highly anticipated to harvest hot electrons in a broad wavelength range. However, the limited absorption and serious backscattering of hot‐electrons result in inadequate quantum yields, especially in the mid‐infrared range. Here, we report a macroscopic assembled graphene (nMAG) nanofilm/silicon heterojunction for ultrafast mid‐infrared photodetection. The assembled Schottky diode works in 1.5–4.0 μm at room temperature with fast response (20–30 ns, rising time, 4 mm2 window) and high detectivity (1.6 × 1011 to 1.9 × 109 Jones from 1.5 to 4.0 μm) under the pulsed laser, outperforming single‐layer‐graphene/silicon photodetectors by 2–8 orders. These performances are attributed to the greatly enhanced photo‐thermionic effect of electrons in nMAG due to its high light absorption (~40%), long carrier relaxation time (~20 ps), low work function (4.52 eV), and suppressed carrier number fluctuation. The nMAG provides a long‐range platform to understand the hot‐carrier dynamics in bulk 2D materials, leading to broadband and ultrafast MIR active imaging devices at room temperature. [ABSTRACT FROM AUTHOR]

D‐π‐A type 4‐((9‐phenylcarbazol‐3‐yl)ethynyl)‐N‐dodecyl‐1,8‐naphthalimide (CZNI) with a large dipole moment of 8.49 D and A‐π‐A type bis[(4,4′‐1,8‐naphthalimide)‐N‐dodecyl]ethyne (NINI) with a negligible dipole moment of 0.28 D, were smartly designed and synthesized to demonstrate the evidence of a molecular dipole as the dominant mechanism for controlling charge separation of organic semiconductors. In aqueous solution, these two novel naphthalimides can self‐assemble to form nanoribbons (NRs) that present significantly different traces of exciton dissociation dynamics. Upon photoexcitation of NINI‐NRs, no charge‐separated excitons (CSEs) are formed due to the large exciton binding energy, accordingly there is no hydrogen evolution. On the contrary, in the photoexcited CZNI‐NRs, the initial bound Frenkel excitons are dissociated to long‐lived CSEs after undergoing ultrafast charge transfer within ca. 1.25 ps and charge separation within less than 5.0 ps. Finally, these free electrons were injected into Pt co‐catalysts for reducing protons to H2 at a rate of ca. 417 μmol h−1 g−1, correspondingly an apparent quantum efficiency of ca. 1.3 % can be achieved at 400 nm. [ABSTRACT FROM AUTHOR]

Long linear carbon chains are attracting intense interest arising from their remarkable properties, such as the tunable direct energy gap, the high mechanical hardness, and the high Raman response cross section, which would play a great role in their potential applications in future nanotechnology. Here the excitonic transitions and the associated relaxation dynamics of nanotube confined long linear carbon chains are comprehensively interrogated by using steady state and time‐resolved Raman spectroscopies. The exciton relaxation dynamics of the confined carbon chains occurs on a hundred of picoseconds timescale, in strong contrast to the host dynamics that occurs on a few picoseconds' timescale. A prominent time‐resolved Raman response is observed over a broad energy range extending from 1.2 to 2.8 eV, which includes the strong Raman resonance region around 2.2 eV. Strong coupling between the chain and the nanotube host is found from the dynamics at high excitation energies which provides clear evidence for an efficient energy transfer from the host carbon nanotube to the chain. The experimental study presents the first unique characterization of the long linear carbon chain exciton dynamics, providing indispensable knowledge for the understanding of the interactions between different carbon allotropes. [ABSTRACT FROM AUTHOR]

Single‐atom metal‐insulator‐semiconductor (SMIS) heterojunctions based on Sn‐doped Fe2O3 nanorods (SF NRs) were designed by combining atomic deposition of an Al2O3 overlayer with chemical grafting of a RuOx hole‐collector for efficient CO2‐to‐syngas conversion. The RuOx‐Al2O3‐SF photoanode with a 3.0 nm thick Al2O3 overlayer gave a >5‐fold‐enhanced IPCE value of 52.0 % under 370 nm light irradiation at 1.2 V vs. Ag/AgCl, compared to the bare SF NRs. The dielectric field mediated the charge dynamics at the Al2O3/SF NRs interface. Accumulation of long‐lived holes on the surface of the SF NRs photoabsorber aids fast tunneling transfer of hot holes to single‐atom RuOx species, accelerating the O2‐evolving reaction kinetics. The maximal CO‐evolution rate of 265.3 mmol g−1 h−1 was achieved by integration of double SIMS‐3 photoanodes with a single‐atom Ni‐doped graphene CO2‐reduction‐catalyst cathode; an overall quantum efficiency of 5.7 % was recorded under 450 nm light irradiation. [ABSTRACT FROM AUTHOR]

The MXenes attract great interest in catalytic and energy applications but suffer from inferior redox activity. An efficient strategy is presented to boost the intrinsic electrochemical activity of MXenes for electrocatalysis in various chemical environments by utilizing their plasmonic response to electromagnetic waves. The resulting significant thermoplasmonic effect lowers the endothermic enthalpy and potential barrier to the hydrogen evolution reaction (HER) in the Vis/near‐IR region. Simultaneous hot‐electron injection in a prolonged sub‐femtosecond to picosecond timescale also remarkably facilitates interfacial charge transfer and decreases the activation energy of the reaction. Both effects boost the HER activity of various types of MXenes over fivefold with improved kinetics and Faradaic efficiency over a broad pH range. [ABSTRACT FROM AUTHOR]

Three‐dimensional (3D) organic–inorganic hybrid perovskites have demonstrated excellent capability in solar fuel production, while the two‐dimensional (2D) counterparts are generally considered inferior candidates due to the high exciton binding energy and weak light absorption. Herein, contrary to our common understanding, we find that 2D perovskites can perform photocatalytic H2 production from HI splitting more efficiently than their 3D counterparts. We observed sharp difference between 2D perovskites crystals with organic phenylalkylammonium cations of different lengths and the 3D counterparts in their stabilization behavior in aqueous solution. Moreover, we show that the organic cations length of the 2D perovskites affects the nanostructures, optoelectronic properties, and the charge transfer process significantly, which determines the photocatalytic activity of the 2D perovskites. Among the 2D perovskites under investigation, phenylmethylammonium lead iodide with the shortest organic cations achieved the best solar‐to‐chemical conversion efficiency of ca. 1.57 %, which is the highest value ever reported for hybrid perovskites. [ABSTRACT FROM AUTHOR]

The design and synthesis of two semiconducting bis (4‐ethynyl‐bridging 1, 8‐naphthalimide) bolaamphiphiles (BENI‐COO− and BENI‐NH3+) to fabricate supramolecular metal–insulator–semiconductor (MIS) nanostructures for biomimetic hydrogen evolution under visible light irradiation is presented. A H2 evolution rate of ca. 3.12 mmol g−1⋅h−1 and an apparent quantum efficiency (AQE) of ca. 1.63 % at 400 nm were achieved over the BENI‐COO−‐NH3+‐Ni MIS photosystem prepared by electrostatic self‐assembly of BENI‐COO− with the opposite‐charged DuBois‐Ni catalysts. The hot electrons of photoexcited BENI‐COO− nanofibers were tunneled to the molecular Ni collectors across a salt bridge and an alkyl region of 2.2–2.5 nm length at a rate of 6.10×108 s−1, which is five times larger than the BENI‐NH3+ nanoribbons (1.17×108 s−1). The electric field benefited significantly the electron tunneling dynamics and compensated the charge‐separated states insufficient in the BENI‐COO− nanofibers. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) have been shown to be an excellent platform in photocatalysis. However, to suppress electron–hole recombination, a Pt cocatalyst is usually inevitable, especially in photocatalytic H2 production, which greatly limits practical application. Herein, for the first time, monodisperse, small‐size, and noble‐metal‐free transitional‐metal phosphides (TMPs; for example, Ni2P, Ni12P5), are incorporated into a representative MOF, UiO‐66‐NH2, for photocatalytic H2 production. Compared with the parent MOF and their physical mixture, both TMPs@MOF composites display significantly improved H2 production rates. Thermodynamic and kinetic studies reveal that TMPs, behaving similar ability to Pt, greatly accelerate the linker‐to‐cluster charge transfer, promote charge separation, and reduce the activation energy of H2 production. Significantly, the results indicate that Pt is thermodynamically favorable, yet Ni2P is kinetically preferred for H2 production, accounting for the higher activity of Ni2P@UiO‐66‐NH2 than Pt@UiO‐66‐NH2. [ABSTRACT FROM AUTHOR]

Triplet energy transfer from inorganic nanocrystals to molecular acceptors has attracted strong attention for high‐efficiency photon upconversion. Here we study this problem using CsPbBr3 and CdSe nanocrystals as triplet donors and carboxylated anthracene isomers as acceptors. We find that the position of the carboxyl anchoring group on the molecule dictates the donor‐acceptor coupling to be either through‐bond or through‐space, while the relative strength of the two coupling pathways is controlled by the wavefunction leakage of nanocrystals that can be quantitatively tuned by nanocrystal sizes or shell thicknesses. By simultaneously engineering molecular geometry and nanocrystal wavefunction, energy transfer and photon upconversion efficiencies of a nanocrystal/molecule system can be improved by orders of magnitude. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (NCs) hold strong promise for a variety of light‐harvesting, emitting, and detecting applications, all of which, however, could be complicated by multicarrier Auger recombination. Therefore, complete documentation of the size‐ and composition‐dependent Auger recombination rates of these NCs is highly desirable, as it can guide system design in many applications. Herein we report the synthesis and Auger measurements of monodisperse APbX3 (A=Cs and FA; X=Cl, Br, and I) NCs in an extensive size range (ca. 3–9 nm). The biexciton Auger lifetime of all the NCs scales linearly with the NC volume. The scaling coefficient is virtually independent of the cation but rather depends sensitively on the anion, and is 0.035, 0.085, and 0.142 ps nm−3 for Cl, Br, and I, respectively. In all of these nanocrystals the Auger recombination is much faster than in standard CdSe and PbSe NCs (ca. 1 ps nm−3). [ABSTRACT FROM AUTHOR]

A highly efficient Z‐scheme photocatalytic system constructed with 1D CdS and 2D CoS2 exhibited high photocatalytic hydrogen‐evolution activity of 5.54 mmol h−1 g−1 with an apparent quantum efficiency of 10.2 % at 420 nm. More importantly, its interfacial charge migration pathway was unraveled: The electrons are efficiently transferred from CdS to CoS2 through a transition atomic layer connected by Co–S5.8 coordination, thus resulting in more photogenerated carriers participating in surface reactions. Furthermore, the charge‐trapping and charge‐transfer processes were investigated by transient absorption spectroscopy, which gave an estimated charge‐separation yield of approximately 91.5 % and a charge‐separated‐state lifetime of approximately (5.2±0.5) ns in CdS/CoS2. This study elucidates the key role of interfacial atomic layers in heterojunctions and will facilitate the development of more efficient Z‐scheme photocatalytic systems. [ABSTRACT FROM AUTHOR]

Phase isomerism is a common and important phenomenon in inorganic materials, but the molecular isomerism of their nanocluster models is still rare. In this work, we report the first pair of isomeric titanium‐oxo clusters. Through combining pentagonal {Ti(Ti5)} building units in corner‐sharing or edge‐sharing forms, the two obtained Ti20‐oxo clusters take vertical and horizontal core configurations, respectively, which are both functionalized by the same organic ligands. More interestingly, the vertical type Ti20‐oxo core contains an identical {Ti8O14} moiety as anatase, making it the first molecular model of anatase TiO2. As a result, the vertical type cluster exhibits better photocatalytic H2 evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. Thus, this work provides a cluster isomer method to understand the structure–property relationship of import titanium oxide materials. Two isomeric Ti20‐oxo clusters with vertical and horizontal core configurations are reported, which show structure‐dependent photoactivities. The vertical type Ti20‐oxo cluster (left in the picture) is the first molecular model of anatase TiO2 (right), exhibiting better photocatalytic H2 evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. [ABSTRACT FROM AUTHOR]

Abstract: Titanium‐based coordination cages could be interesting for both supramolecular and photophysical chemistry. This work reports an unprecedented host–guest system, [Ti(H2O)6]@Ti8L12, which is comprised of the first Ti‐based coordination cube and the unusual titanium aquo species. Due to the abundant intra‐cube O−H⋅⋅⋅O hydrogen bonds, the [Ti(H2O)6]@Ti8L12 complex is rather stable both in solid and solution states, confirmed by X‐ray diffraction and ESI‐MS analysis. The encapsulated [Ti(H2O)6] species shows influence on the light absorption, photoluminescent, and photocurrent properties. Moreover, ultrafast transient absorption spectroscopy has been applied to study the photodynamics of both free and [Ti(H2O)6] guest encapsulated Ti8L12 cube, confirming that the host–guest system produces a slightly longer‐lived excited state. Therefore, this work presents the first [Ti8L12] cube with unusual [Ti(H2O)6] guest and also provides an interesting supramolecular model for the host–guest photophysical study. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites (RPPs) have emerged as a promising solar cell material. A group of novel RPPs with cyclohexane methylamine (CMA) as a spacer cation is presented. Unlike previously reported RPPs, the deposited films of (CMA)2(MA)n−1PbnI3n+1 (MA is CH3NH3+, n = 1, 2, 3, ...) exhibit multiple phases with reverse‐graded quantum well (QW) distribution; small n (n = 2) RPPs are located at the surface and large n (n ≥ 10) RPPs at the bottom. This has three advantages: (a) The outer, more moisture resistant, small n RPPs create a stable barrier that protects the vulnerable large n RPP lattice from being attacked by water molecules. (b) It forms a type‐II band alignment between different phases, which favors self‐driven charge transport. (c) The natural structure of graded QWs expands the range of photon collection. Attributed to these properties, the best efficiency of 15.05%, with high open‐circuit voltage (Voc) of 1.10 V for a first‐generation solar cell containing (CMA)2(MA)8Pb9I28, is achieved. A notable enhancement in short wavelength is observed in the Incident photon‐to‐current conversion efficiency spectra. This device shows significantly improved long‐term stability, retaining ≈95% of the initial efficiency after 4600 h exposure in ambient conditions with 40–70% relative humidity. [ABSTRACT FROM AUTHOR]

Review: 293 refs. [ABSTRACT FROM AUTHOR]