Conjugated Naphthalenediimide-Pyridinium Salts in Donor-Acceptor Hybrid Materials for Enhanced Photochromic Properties.

As an emerging class of hybrid materials, donor-acceptor (D-A) hybrid crystals with photoactive organic and inorganic components have gradually become an ideal platform for photochromic materials. Wherein the most available organic components are electron-poor naphthalenediimide, pyridinium, and triazine derivatives, inorganic units are electron-rich polyoxometalates and metal halides. Herein, we introduced pyridinium moieties into the naphthalenediimide core by conjugated bonds so as to increase the electron deficiency of organic species for enhanced photochromic properties.

Organic Phosphonium Side-Chain Engineering in Metal Halide Glassy Scintillators for Enhanced X-Ray Dynamic Imaging.

X-ray imaging utilizing organic-inorganic hybrid metal halide (OIHMH) glassy scintillators has garnered significant attention. But their inferior radioluminescence makes achieving rapid image acquisition difficult, posing a persistent challenge for dynamic imaging. Herein, organic phosphonium halide side-chain engineering is proposed, introducing bulky aromatic rings at the alkyl chain ends, to improve the radioluminescence of OIHMHs.

A hot exciton organic glassy scintillator for high-resolution X-ray imaging.

Hot exciton organic scintillators offer promising prospects due to their efficient generation of bright triplet excitons and ultrafast response time, having potential applications in security detection and medical diagnostics. However, fabricating large-area, highly transparent scintillator screens still remains challenging, impeding the realization of high-resolution X-ray imaging. Herein, we firstly demonstrate a novel highly-transparent hot exciton organic glassy scintillator (>87% transmittance @ 450-800 nm), produced using a low-temperature melt-quenching method with 2',5'-difluoro-4,4,4'',4''-tetraphenyl-[1,1':4',1''-terphenyl]-4,4''-diamine (DTPA2F) powder.

Enhanced Stability of Melt-Processable Organic-Inorganic Hybrid Manganese Halides for X-Ray Imaging.

Mn-based metal halides scintillators with high photoluminescence quantum yield (PLQY) have recently emerged as promising large-size candidates for X-ray imaging but still remains as difficult challenge in stability and high processing temperatures. Here, three manganese halides are designed by introducing branched chains into organic cations and extending the carbon chains, namely (i-PrTPP)MnBr, (i-BuTPP)MnBr and (i-AmTPP)MnBr, successfully lowered the melting point of manganese halides to 120.2 °C.

Mechanochemical Synthesis of Cuprous Complexes for X-ray Scintillation and Imaging.

Cuprous complex scintillators show promise for X-ray detection with abundant raw materials, diverse luminescent mechanisms, and adjustable structures. However, their synthesis typically requires a significant amount of organic solvents, which conflict with green chemistry principles. Herein, we present the synthesis of two high-performance cuprous complex scintillators using a simple mechanochemical method for the first time, namely [CuI(PPh)R] (R = 4-phenylpyridine hydroiodide (PH, Cu-1) and 4-(4-bromophenyl)pyridine hydroiodide (PH-Br, Cu-2).

Polyoxometalate/-triazine hybrid heterostructures with ultrafast photochromic properties.

As an emerging class of hybrid complexes, donor-acceptor (D-A) hybrid heterostructures, which combine the advantages of both organic and inorganic photoactive components, provide excellent platforms for the fabrication of photochromic materials with enhanced photo-responsive performances. Herein, four novel hybrid heterostructures, namely HTPT·(PWO)·2NMP (1), (HTPT)·(PWO) (2), (HTPT)·(SiWO)·2Cl·2MeCN (3), and HTPT·(HPMoO)·Cl·3NMP (4) (TPT is tri(4-pyridyl)--triazine, NMP is -methylpyrrolidone), have been synthesized and characterized. Benefitting from the strong interactions (anion-π interactions) and matching electron energy levels between the donors and acceptors, some of them exhibited ultrafast photochromic behaviour even up to 1 second.

Donor-Acceptor Hybrid Heterostructures: An Emerging Class of Photoactive Materials with Inorganic and Organic Semiconductive Components.

Just as the heterojunctions in physics, donor-acceptor (D-A) heterostructures are an emerging class of photoactive materials fabricated from two semiconductive components at the molecular level. Among them, D-A hybrid heterostructures from organic and inorganic semiconductive components have attracted extensive attention in the past decades due to their combined advantages of high stability for the inorganic semiconductors and modifiability for the organic semiconductors, which are particularly beneficial to efficiently achieve photoinduced charge separation and transfer upon irradiations. In this review, by analogy with the heterojunctions in physics, a definition of the D-A heterostructures and their general design and synthetic strategies are given.

Photochromic Polyoxometalate/Perylenediimide Donor-Acceptor Hybrid Crystals with Interesting Luminescent Properties.

The self-assembly of electron-deficient protonated , '-dipyridyltetrachloroperylenediimide (4Cl-DPPDI) and electron-rich polyoxometalate acids HXMO (POMs; X = P or Si; M = W or Mo) resulted in four isomorphous donor-acceptor hybrid crystals - with segregated POM anions and one-dimensional racemic hydrogen-bonded 4Cl-DPPDI networks as electron-donor and -acceptor components, respectively. Because of the compact contacts between the POM anions and 4Cl-DPPDI tectons induced by anion-π interactions, besides enhanced photochromism, these four unique isostructural hybrids exhibited unusual room-temperature phosphorescence (RTP) emissions. More interestingly, owing to the facial compact contacts of two racemic 4Cl-DPPDI tectons induced by lone pair-π-assisted π-π interactions, they also showed unprecedented photon upconversion by triplet-triplet annihilation (TTA).

Photochromic and Room Temperature Phosphorescent Donor-Acceptor Hybrid Crystals Regulated by Core-Substituted Naphthalenediimides.

Donor-acceptor (D-A) hybrid crystals are an emerging kind of crystalline hybrid material composed of semiconductive inorganic donors and organic acceptors. Except for the intrinsic photochromism, recently we have reported that the anion-π polyoxometalate (POM)/naphthalenediimide (NDI) hybrid crystals could produce an interesting room temperature phosphorescence (RTP) quantum yield up to 7.2%.