Additional file 1 of Elucidating the degradation pattern of a new cold-tolerant pectate lyase used for efficient preparation of pectin oligosaccharides

Additional file 1: Table S1. The primers for cloning the gene of pectate lyase ErPelPL1

N‑Doped Carbon Dots Embedded in Silica Nanoparticles with Multicolor Luminescence for Light-Emitting Devices

To overcome the aggregation-caused quenching of carbon dots (CDs) in the solid state, this work presented a facile approach for in situ synthesis of N-doped CDs (N-CDs) in silica particles with the assistance of a bifunctional organic base, tetramethylammonium hydroxide (TMAOH). In this approach, TMAOH first acted as a basic catalyst, which can dissociate into TMA+ and OH–, to direct the growth of TMA+-embedded SiO2 particles. The TMA+ in silica particles was then used as the precursor for in situ synthesis of N-CDs via pyrolysis, resulting in the formation of N-CD-embedded SiO2 (N-CDs/SiO2) particles. The N-CDs/SiO2 particles presented tunable emission color from blue to green and yellow, depending on the amounts of TMAOH used in the reactions. More importantly, the resulting N-CDs/SiO2 particles exhibited bright and stable emission in both solution and solid states, making them potentially useful in the fabrication of anti-counterfeiting labels and light-emitting devices

Exciton–Phonon Coupling and Low Energy Emission in 2D and Quasi-2D BA₂MA_<i>n</i>–1Pb_<i>n</i>I_3<i>n</i>+1 Thin Films with Improved Phase Purity

Phonon scattering with photogenerated excitons and free charges greatly affects optoelectronic properties of metal halide perovskites and governs their emission line width. Benefiting from the improved phase purity, we are able to analyze exciton–phonon coupling in 2D and quasi-2D BA2MAn–1PbnI3n+1 (n = 1–3) thin films using temperature-dependent photoluminescence (PL) spectroscopy. The layer thickness (n value) dependent coupling of free excitons with both acoustic and longitudinal optical (LO) phonons was extracted quantitatively by fitting the temperature-dependent PL line width and band gap. The low energy emissive signatures below free excitons at low temperature might belong to the emission of self-trapped excitons and bounded excitons in structural defects. Our findings provide a systematic picture for the layer thickness (n value) dependent exciton–phonon coupling in 2D and quasi-2D perovskite thin films and could be helpful for improving the optoelectronic performance of devices made by Ruddlesden–Popper perovskite thin films

Exciton–Phonon Coupling and Low Energy Emission in 2D and Quasi-2D BA₂MA_<i>n</i>–1Pb_<i>n</i>I_3<i>n</i>+1 Thin Films with Improved Phase Purity

Phonon scattering with photogenerated excitons and free charges greatly affects optoelectronic properties of metal halide perovskites and governs their emission line width. Benefiting from the improved phase purity, we are able to analyze exciton–phonon coupling in 2D and quasi-2D BA2MAn–1PbnI3n+1 (n = 1–3) thin films using temperature-dependent photoluminescence (PL) spectroscopy. The layer thickness (n value) dependent coupling of free excitons with both acoustic and longitudinal optical (LO) phonons was extracted quantitatively by fitting the temperature-dependent PL line width and band gap. The low energy emissive signatures below free excitons at low temperature might belong to the emission of self-trapped excitons and bounded excitons in structural defects. Our findings provide a systematic picture for the layer thickness (n value) dependent exciton–phonon coupling in 2D and quasi-2D perovskite thin films and could be helpful for improving the optoelectronic performance of devices made by Ruddlesden–Popper perovskite thin films

Aggregation-Enhanced Emission of Gold Nanoclusters Induced by Serum Albumin and Its Application to Protein Detection and Fabrication of Molecular Logic Gates

Exploring aggregation-enhanced emission (AEE) of gold nanoclusters (Au NCs) is beneficial for extending their applications in sensing and molecular information processing. Herein, we present the first report of a protein-induced AEE effect of Au NCs. When human serum albumin (HSA) is mixed with glutathione-capped Au NCs under appropriate pH conditions, the Au NCs undergo extensive aggregation and exhibit significantly enhanced emission, attributed to the electrostatic and hydrophobic interactions between HSA and the NCs. Such an AEE effect is specific to serum albumin over a variety of other proteins, which facilitates the development of a facile approach for HSA determination. This sensing method displays satisfactory recoveries of 96.0–98.7% when it is applied to HSA detection in artificial urine. Moreover, the AEE effect is suited to the fabrication of AND and INHIBIT logic gates by using HSA and pH/protein-binding drug as inputs and the emission as output

Phase Engineering of Hydrophobic Meso-Environments in Silica Particles for Technical Performance Enrichment

Hexadecyltrimethylammonium bromide (CTAB) was utilized to template the growth of mesoporous silica particles via ammonia-catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS) in the reaction solutions with varied volume fractions of ethanol (<i>f</i>_R). The use of 9,10-bis­(phenylethynyl) anthracene (BPEA) as a fluorescence probe unraveled a clear difference in interior structure between the CTAB micelles confined at different <i>f</i>_R. At <i>f</i>_R of 0.3, the confined CTAB micelles consisting of regularly and densely packed alkane chains, which created crystalline interiors, in which the doped BPEA molecules were effectively isolated in the monomeric form and well protected against aggressive attack from the surrounding environment. At <i>f</i>_R of 0.4 or 0.5, the confined CTAB micelles consisting of less regularly but densely packed alkane chains created glassy interiors, which enabled reversible aggregation of the doped BPEA in response to the surrounding environmental change, for instance, the ethanol content in the particle dispersion. At <i>f</i>_R of 0.6 or 0.7, the confined CTAB micelles consisting of loosely packed alkane chains created amorphous interiors, which offered sufficiently large free spaces to facilitate the material exchange with the surrounding environment, as evidenced by noticeable intake of the Pyronin Y molecules present in the particle dispersion. The revealed phase modulation of the interiors of surfactant micelles, confined in the pores of mesoporous particles, from crystalline to glassy and amorphous structures, which were scarcely reported in literature, will inspire rational design of mesoporous silica particles with desired technical performance according to the purposes of the practical application

Ternary Assemblies of TADF Core/TDBC-J-Aggregate Shell Nanoparticles and d/l‑Phenylalanine-Based Nanohelixes for Circularly Polarized Luminescence

Developing pure organic nanostructures with circularly polarized luminescence (CPL) response is of high interest for the community. As ordered nanoassemblies of a conjugated dye, the J-aggregate exhibits an ultra-narrow emission bandwidth, a high radiative rate, and a largely red-shifted emission but has been rarely employed for constructing a CPL system due to the minimized Stokes shift and the rigorous condition of assembling. In this work, we developed a simple strategy of ternary co-assembling to facilitate narrowband CPL response of cyanine J-aggregates, in which J-aggregate emitters were co-assembled as a shell of light harvester nanoparticles to form the core–shell structures in the nanoscale. Taking advantage of the core–shell energy transfer (FRET) and chiral transfer from assembled nanohelixes to J-aggregate emitters, the narrowband (fwhm <10 nm and centered at ∼585 nm) CPL response of TDBC-J was demonstrated with a dissymmetric factor glum of ±1 × 10–3. Our work provides a simple approach to facilitate narrowband CPL response from J-aggregates in an aqueous solution, which might be able to offer opportunities to achieve CPL response in a greatly red-shifted even near-infrared regime with potential applications

Tuning Hybridized Local and Charge-Transfer Mixing for Efficient Hot-Exciton Emission with Improved Color Purity

Delayed fluorescence (DF) emitters with high color purity are of high interest for applications in high-resolution displays. However, the charge transfer required by high emitting efficiency usually conflicts with the expected color purity. In this work, we investigated the S1/S0 conformational relaxation, spin–orbital coupling (SOC), and vibronic coupling of hot-exciton emitters while hybrid local and charge transfer (HLCT) state tuning was achieved by a structural meta-effect. The meta-linkage leads to suppressed S1/S0 conformational relaxation and weakened vibronic coupling, while the unsacrificed emitting efficiency is largely ensured by multiple rISC channels (Tn → Sm) with thermally accessible triplet–singlet energy gap (ΔEST) and effective SOC. We demonstrated that the unique excited-state mechanism provides opportunities to improve the emitting color purity of hot-exciton emitters without sacrificing emitting efficiency by HLCT state tuning with simple chemical structural modification, for which hot-exciton emitters might play a more important role for high-resolution organic light-emitting diode displays

Photoacid-Loaded Nanopores of Hollow Mesoporous Organosilica Capsules for Fluorescent Humidity Sensing

Humidity sensing has a wide application and receives intense attention from a broad spectrum of research areas. In this work, we demonstrated a robust humidity sensing strategy by loading photoacid HPTS (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt) into nanopores of hollow mesoporous organosilica (HMO) capsules. Taking advantage of the capillary condensation of nanopores, water vapor is enriched, which triggers the fluorescent color change of HPTS through intermolecular excited-state proton transfer (ESPT) for humidity sensing. The ESPT induced fluorescent color change behavior of HPTS loaded in nanopores was comprehensively investigated by using both steady and picosecond time-resolved fluorescence spectroscopy. The fabricated humidity sensors exhibit rapid response and recovery, qualified reversibility, and selectivity, which enable continuous monitoring of human respiration. Notably, the sensing performance, i.e., sensitivity and response range, can be effectively tuned by fabricating HMO capsules with properly sized nanopores, which provides an opportunity to design unique nanostructures of the humidity sensor for specific applications

Tuning Hybridized Local and Charge-Transfer Mixing for Efficient Hot-Exciton Emission with Improved Color Purity

Delayed fluorescence (DF) emitters with high color purity are of high interest for applications in high-resolution displays. However, the charge transfer required by high emitting efficiency usually conflicts with the expected color purity. In this work, we investigated the S1/S0 conformational relaxation, spin–orbital coupling (SOC), and vibronic coupling of hot-exciton emitters while hybrid local and charge transfer (HLCT) state tuning was achieved by a structural meta-effect. The meta-linkage leads to suppressed S1/S0 conformational relaxation and weakened vibronic coupling, while the unsacrificed emitting efficiency is largely ensured by multiple rISC channels (Tn → Sm) with thermally accessible triplet–singlet energy gap (ΔEST) and effective SOC. We demonstrated that the unique excited-state mechanism provides opportunities to improve the emitting color purity of hot-exciton emitters without sacrificing emitting efficiency by HLCT state tuning with simple chemical structural modification, for which hot-exciton emitters might play a more important role for high-resolution organic light-emitting diode displays