Donor Energy Levels Research Articles

Solvent Effects on Spin-Orbit Charge-Transfer Intersystem Crossing in Aryl-Substituted Boron-dipyrromethene Donor-Acceptor Dyads.

In heavy-atom-free organic molecules, the rate of triplet generation through charge recombination, as dictated by the El-Sayed rule, can be enhanced by 101-102 times compared with the rate of spontaneous spin flipping between π-π* orbitals. This mechanism is known as the spin-orbit charge-transfer intersystem crossing (SOCT-ISC). Within the framework of the SOCT-ISC mechanism, facilitating the generation of charge-separated (CS) states and suppressing the spin-allowed direct charge recombination to the ground state are pivotal for maximizing the efficiency of generating localized triplet states. Herein, a series of orthogonal aryl-substituted boron-dipyrromethene dyads were studied by time-resolved spectroscopy to unravel the multichannel competitive relationships in the SOCT-ISC mechanism. The energy level of the electron donor and the stabilization of the solvent effect to the charge-transfer state are reflected in the Gibbs free energy changes of the electron transfer and recombination reactions, leading to significantly different triplet quantum yields. Additionally, solvation-induced electronic coupling changes in excited states lead to the fact that the spin-allowed charge recombination rate cannot be well simply predicted by the Marcus inverted region but has to consider the specific excited-state dynamics in optimizing the proportion of triplet generation channels based on charge recombination.

Theoretical study on the synthetic pathway of H and N co-doped diamonds

To search for potential n-type diamonds with shallow donor energy levels and low formation energies, the reaction energies, geometries, formation energies, electronic properties of hydrogen (H) and nitrogen (N) co-doped diamond have been investigated by density functional theory (DFT) and hybrid density functional theory (HSE06). The results of the investigations on isolated H- and N-doped diamonds do not meet the criteria for shallow n-type donors, in agreement with previous findings. Subsequently, the effect of the addition of N atoms as a co-dopant with H is investigated, which varies with the H:N ratio and whether H is substitutional or interstitial. By the results of the electronic structure, it is found that only the HN4 co-doped diamond is likely to exhibit a shallow donor, with a shallow donor level of 0.147 eV and formation energy of 0.02 eV. Then, the stability of the HN4 defect is analyzed, and the HN4 defect is more stable compared to the H-N3 + N and H-N2 + N2 defects, and its decomposition energy is also very large. Further, the bond strain brought by HN4 defect is considered, showing that the local bond strain of the HN4 defect is intermediate between that of the boron (B) and N defects, which proves that the defect can be realized. Finally, a non-molecular synthetic route for the preparation of HN4 defect is proposed by combining H-N + N3V or N2 + H-N2 defects.

Charge engineering in black phosphorene with tunable electronic structures as efficient oxygen evolution electrocatalyst

The unique electronic structure of layered black phosphorus (BP) makes it an ideal candidate material for electrocatalytic oxygen evolution reaction (OER). Charge doping effectively improves the environmental stability and catalytic activity of BP by providing electron transfer channels and reducing charge transfer barrier. Therefore, based on the first principles calculation, this paper theoretically discusses how the intrinsic charge doping without introducing impurities changes the electronic structure and improves the catalytic activity of BP. It is found that charge engineering can effectively regulate and change the electronic structure and work function by stimulating the hybridization between different P-p orbitals, while maintaining the direct bandgap semiconductor characteristics of monolayer BP system. More importantly, in the catalytic process of OER, electrons and hole doping as free charges provide different donor and acceptor energy levels for the system depending on the doping concentration, and affect the adsorption capacity of monolayer BP to different reaction intermediates. At a certain doping concentration, the carrier mobility increases significantly, and the optimal Gibbs free energy and overpotential can be achieved in monolayer BP. These results provide new opportunities and possibilities for designing charge-engineered BP catalysts with adjustable electronic structure and excellent OER activity.

Specificity of electrophysical and gas-sensitive properties of nanocomposite ZnO–TiO2 films formed by solid-phase pyrolysis

ZnO–TiO2 thin films containing 0.5 mol%, 1.0 mol%, and 5.0 mol% ZnO were synthesized by oxidative solid-phase pyrolysis. The materials contained anatase and rutile phases with particle size of 6–13 nm, as confirmed using X-ray phase analysis and scanning electron microscopy. When a certain number of ZnO crystallites appeared in the TiO2 film structure in the temperature range of room temperature to 220 °C, a two-level response of the film resistance was observed, differing by approximately 10%, as obtained by electrophysical measurements. The two-level response correlates with the formation of two donor energy levels of 0.28 and 0.33 eV in the band structure of the ZnO–TiO2 films. The donor level with a higher activation energy corresponded to the Ti vacancy (V−Ti), and that with a lower activation energy corresponded to the Zn vacancy (V−Zn). Two levels of gas-sensitive properties were noted for 0.5ZnO–TiO2, 1ZnO–TiO2, and 5ZnO–TiO2 under the influence of 50 ppm NO2 at 250 °C. Such two-level responses can be ascribed to the pinning of the Fermi level on ZnO and TiO2 nanocrystallites. The mechanism of the beak-shaped and two-level responses of sensors based on composite nanomaterials when exposed to various gases was elucidated.

Charge transport and extrinsic absorption of two-dimensional defect-rich ZnIn2S4 semiconductor for below-bandgap photodetection

As a rediscovered ternary two-dimensional (2D) material, defect-rich Znln2S4 has great potential for energy-harvesting applications. However, the effect of defects on its physical properties and device performance remains elusive. Herein, we explored the influence of defects (S vacancies and In–Zn substitutions) in few-layer Znln2S4 on the charge transport and photoelectric performance. It is demonstrated that the defect-rich Znln2S4 device exhibits two-dimensional variable range hopping transport mechanism, with uniform charge transport along the channel and low contact resistance at the electrical contacts of Znln2S4/Au. Importantly, due to the contribution of the donor and acceptor energy levels inside the bandgap, the flake exhibits pronounced extrinsic absorption, leading to the competitive photodetector performance under sub-bandgap photo-excitation. Explicitly, the device exhibits a maximum responsivity of 4.08 × 104 A W−1, a photo-gain of >108 electrons per photon, and a specific detectivity of ∼1015 Jones under 532 nm laser excitation, with detection wavelength extending from 400 to 980 nm. Our findings underscore the significant potential of defect-engineering to enrich the functionalities of 2D semiconductors.

Cobalt-induced localized electronic reconstruction and global band structure adjustment enhance photo-Fenton-like activity in iron-based metal–organic frameworks

Modulations in interatomic localized electron density and occupation states are vital for facilitating efficient Photo-Fenton-like reactions in iron-based metal–organic frameworks (Fe-MOFs). Here, Co-doped Fe-MOFs (FeCox-MOFs) were synthesized through a one-step hydrothermal method, introducing Co(II) with a distinct Jahn-Teller effect and electronegativity. This led to local ligand deficiency, forming exposed Fe-O-Co clusters. This integration facilitated Co coordinatively unsaturated sites (CUSs) to partially acquire electrons from adjacent Fe CUSs, further optimizing the d-band center. As a result, the d-band centers of both Fe (-1.32 eV) and Co (-1.52 eV) CUSs in FeCo2/1-MOFs were higher than that of Fe sites (-1.87 eV) in Fe-MOFs, resulting in enhanced adsorption capability of persulfate (PMS). Notably, Co(II) underwent ligand-driven electron redistribution, populating antibonding orbitals (eg*) and increasing their energy, thereby elevating the conduction band. Concurrently, Co 3d orbitals served as donor energy levels, narrowing the band gap. With the tuned band structure, the eg* of Fe(III) sites experienced rapid electron population upon photoexcitation, expediting Co(III) reduction and enhancing PMS activation. This study provides a unique perspective on the catalytic application of FeCox-MOFs in photo-Fenton-like reactions.

G-C3N4@CPP/BiOClBr-OV biomimetic fractal heterojunction synergistically enhance carrier dynamics for boosted CO2 photoreduction activity

In recent years, there has been significant interest in generating high-value solar fuels via the photocatalytic reduction of CO2. Nonetheless, its large-scale application is impeded by low energy utilization efficiency and limited photocatalytic activity. This study employed carbonized pomelo peel (CPP), a waste biomass material, to successfully craft a CN@CPP/BOCB-OV ternary heterojunction abundant in N/O vacancy defects through secondary calcination and in-situ growth. The construction of the heterojunction and the emergence of defect-induced donor energy levels create a built-in interface electric field (IEF) and an interfacial electron transmission channel respectively, fortifying the separation and transport of photogenerated electrons. Crucially, following the incorporation of CPP, its distinctive 3D porous and heterojunction bionic flower structures expand the spectral absorption range. Acting as a superior electron acceptor, CPP reinforces the IEF, notably boosting carrier transport efficiency. Simultaneously, it operates as a hub for photothermal synergy and CO2 adsorption activation, achieving multi-site synergistic enhancement of photoreduction CO2 activity. Hence, the CN@CPP/BOCB-OV heterojunction demonstrates a substantial quantitative enhancement in CO2 photoreduction activity. Remarkably, it exhibits the capability to catalyze CO2 reduction even under infrared light excitation, which is of great significance for the cascade utilization of solar energy. Furthermore, employing DFT calculations, we elucidate the electron transfer mechanism at the heterojunction interface and outline potential pathways for photocatalytic CO2 reduction. The combination of waste biomass utilization, heterostructure construction and defect engineering provides a promising strategy for developing efficient heterostructure photocatalysts.

Accelerating Ce3+/Ce4+ Conversion in CeO2 via Mn doping to Endow Scaffolds with Chemodynamic Therapy Properties

CeO2 nanozymes have garnered significant attention in chemodynamic therapy due to their peroxidase-like activity and ability to deplete glutathione. However, their catalytic efficiency is constrained by the low conversion rate of Ce3+/Ce4+. To overcome this limitation, the electron transfer was accelerated by introducing the transition metal Mn atom as a valence electron donor through lattice charge transfer. In detail, we introduced Ce1-xMnxO2 into the poly-L-lactic acid (PLLA) scaffold fabricated by selective laser sintering. The conversion from Ce3+ to Ce4+ promoted the decomposition of H2O2 within the tumor microenvironment to generate hydroxyl radicals with high oxidative activity, consequently inducing oxidative stress. The conversion from Ce4+ to Ce3+ depleted intracellular antioxidant glutathione, disrupting redox balance in tumor cells. This continuous redox cycle ultimately triggered apoptosis in tumor cells. Using a first-principles Hubbard-corrected approximate density-functional method, the analysis of the electron band structure revealed the presence of donor energy levels within the bandgap of Ce1-xMnxO2, enabling electron transfer channels around 0.645 eV. Electrochemical experiments confirmed that Ce0.8Mn0.2O2 significantly reduced the activation overpotential from 0.907 V to 0.646 V, enhancing its redox capacity. As a result, the scaffold exhibited a threefold increase in tumor-killing rate. These findings highlight the immense potential of CeO2 nanozymes in enhancing chemodynamic therapy for effective tumor treatment.

Synergistic mediation of dual donor levels in CNS/BOCB-OV heterojunctions for enhanced photocatalytic CO2 reduction

Construction of CNS/BOCB-OV heterostructures with N/O vacancies leads to new donor energy levels that create a new pathway for interfacial charge transfer to improve charge separation and enhance photocatalytic activities for CO2 reduction.

Vaporization phosphorization-mediated synthesis of phosphorus-doped TiO2 nanocomposites for combined photodynamic and photothermal therapy of renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is a disease with high incidence and poor prognosis. The conventional treatment involves radiotherapy and chemotherapy, but chemotherapeutic agents are often associated with side effects, i.e., cytotoxicity to nontumor cells. Therefore, there is an urgent need for the development of novel therapeutic strategies for ccRCC. We synthesized spherical P/TiO2 nanoparticles (P/TiO2 NPs) by vaporization phosphorization (VP). X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) analyses confirmed that the anatase TiO2 surface was successfully doped with phosphorus and produced a large number of oxygen vacancies (OV). Serving as a photosensitizer, P/TiO2 NPs not only extended the photoresponse range to the near-infrared II region (NIR II) but also introduced a donor energy level lower than the TiO2 conduction band, narrowing the band gap, which could facilitate the migration of photogenerated charges and trigger the synergistic treatment of photodynamic therapy (PDT) and photothermal therapy (PTT). During NIR irradiation in vitro, the P/TiO2 NPs generated local heat and various oxygen radicals, including 1O2, ˙O2-, H2O2, and ˙OH, which damaged the ccRCC cells. In vivo, administration of the P/TiO2 NPs + NIR reduced the tumor volume by 80%, and had the potential to inhibit tumor metastasis by suppressing intratumor neoangiogenesis. The P/TiO2 NPs showed superior safety and efficacy relative to the conventional chemotherapeutic agent used in ccRCC treatment. This study introduced an innovative paradigm for renal cancer treatment, highlighting the potential of P/TiO2 NPs as safe and effective nanomaterials and presenting a compelling new option for clinical applications in anticancer therapy.

Oxygen-doped colloidal GaN quantum dots with blue emission

Gallium nitride quantum dots (GaN QDs), as a third-generation semiconductor material, are usually synthesized through a vapor deposition method at an elevated temperature (typically ≥800 °C). Thermal injection method is rarely reported for the synthesis of GaN QDs due to the lack of active precursors and the require of harsh reaction conditions. Here, we report the fabrication of oxygen doped colloidal GaN QDs via rapid thermal injection. By screening the reaction temperature and solvent, well-dispersed GaN QDs with a size of 3.8 nm were obtained in octadecylamine (ODA) at 360 °C. The synthesized GaN QDs show blue emission, the maximum emission wavelength is about 440 nm, and the photoluminescence quantum yield is 14.3%. Furthermore, we reveal the donor-acceptor mechanism of blue emission from GaN QDs. During the growth of GaN QDs, oxygen atoms occupy some nitrogen sites and produce a shallow oxygen donor energy level (ON). A part of the ON can be combined with the adjacent gallium vacancy (VGa) to form a VGa-ON acceptor, whose energy level is about 0.98 eV above the valence band of GaN QDs. The transition of excited electrons from the donor (ON) to the acceptor (VGa-ON) is responsible for the blue emission of GaN QDs.

Synthetic pathway of shallow n-type donor: Theoretical study of Li and B co-doped diamonds

To find potential n-type diamonds with shallow donor energy levels and low formation energies, the thermodynamic and electronic properties of Lithium-Boron (LiB) co-doped diamonds have been investigated using density functional theory (DFT) and hybrid density functional theory (HSE06). The structure, formation energy, electronic property and the potential synthesis pathway are analyzed. The results of the single Li defect is not a suitable candidate for a shallow n-type donor, as it distorts the diamond lattice and forms clusters, in agreement with previous work. The calculated ionization energy of Lii2-B defect (0.29 eV) and the impurities formation energy (0.196 eV) is much lower than that of Lii defect. It suggests that the introduction of B helps improve the solubility of Li in diamond. Further structural analysis has shown that the incorporation of B atoms inhibits the diffusion of Li atoms and simultaneously reduces the internal strain in the diamond, resulting in a significant reduction in the distance between the two lithium atoms from 2.061 Å to 1.629 Å. At last, a non-molecular synthesis pathway of Lii2-B co-doped diamond is proposed via prior generation of B-doped diamond at which Li atom is mobile which indicates there is a potential window-of-opportunity to prepare Lii2-B co-doped diamond to achieve n-type diamond.

Creating oxygen vacancies on porous tungsten oxide nanospheres via one-step muffle calcination for ultra-fast detection of ppb-level hydrogen sulfide sensors

Exploring the relationship between tungsten oxides with a controlled amount of oxygen vacancies and their gas-sensing properties with respect to hydrogen sulfide is interesting for developing excellent comprehensive gas-sensing performance materials with fast and accurate response. In this work, the WO3 nanoparticles with oxygen defective structure were synthesized by a straightforward one-step muffle calcining method. The WO3 nanoparticles prepared at the calcination temperature of 600 ℃ (Ov-WO3-600) display the high response value (2777) and ultra-fast response time (2 s) to 5 ppm hydrogen sulfide (H2S) at 100 ℃. Moreover, it also exhibits low practical detection limit (100 ppb), long-term stability, as well as remarkable admirable selectivity. The gas sensing mechanism can be explained by the fact that oxygen vacancies, as donor energy levels provide more electrons, increase the carrier mobility and narrow the band gap. This makes it easier for oxygen to capture electrons to form more adsorbed oxygen, which improves the gas sensing performance of WO3-based sensors. Hence, our study can offer guidance for the construction of fast and accurate sensing materials based on WO3.

Defect Emission and Its Dipole Orientation in Layered Ternary Znln2 S4 Semiconductor.

Defect engineering is promising to tailor the physical properties of 2D semiconductors for function-oriented electronics and optoelectronics. Compared with the extensively studied 2D binary materials, the origin of defects and their influence on physical properties of 2D ternary semiconductors are not clarified. Here, the effect of defects on the electronic structure and optical properties of few-layer hexagonal Znln2 S4 is thoroughly studied via versatile spectroscopic tools in combination with theoretical calculations. It is demonstrated that the Zn-In antistructural defects induce the formation of a series of donor and acceptor energy levels and sulfur vacancies induce donor energy levels, leading to rich recombination paths for defect emission and extrinsic absorption. Impressively, the emission of donor-acceptor pair in Znln2 S4 can be significantly tailored by electrostatic gating due to efficient tunability of Fermi level (Ef ). Furthermore, the layer-dependent dipole orientation of defect emission in Znln2 S4 is directly revealed by back focal plane imagining, where it presents obviously in-plane dipole orientation within a dozen-layer thickness of Znln2 S4 . These unique features of defects in Znln2 S4 including extrinsic absorption, rich recombination paths, gate tunability, and in-plane dipole orientation are definitely a benefit to the advanced orientation-functional optoelectronic applications.

Different Energetics at Donor:Acceptor Interfaces in Bilayer and Bulk‐Heterojunction Polymer:Non‐Fullerene Organic Solar Cells

To understand the limitations placed on the open‐circuit voltage of bulk heterojunction (BHJ) organic solar cells, the energy levels of neat donor and acceptor samples are often characterized and applied to study BHJ blends. However, energy levels derived from neat samples may not necessarily reflect those at the donor:acceptor interface in blends. The properties of organic semiconductors are sensitive to microstructural changes, with non‐fullerene acceptors (NFAs) in particular known to exhibit different thin‐film polymorphs. To investigate the influence of differences in molecular packing in neat and blend films, temperature‐dependent current–voltage characteristics are measured for bilayer (BL) and BHJ devices. Herein, the fullerene acceptor PC71BM is compared—whose energy levels are expected to be less sensitive to molecular packing—with the NFA ITIC, paired with the same donor polymer PTB7‐Th. It is found that the interfacial energy levels differ for BL and BHJ devices for the PTB7‐Th:ITIC system but remain the same for the PTB7‐Th:PC71BM system. Furthermore, X‐ray scattering measurements identify that ITIC exhibits a different packing mode in neat films and in BHJ blends. Such microstructure‐dependent differences between neat and blend samples need to be considered when studying energy losses in NFA BHJ solar cells.

Creating zinc-hyperdoped silicon with modulated conduction type by femtosecond laser irradiation

Silicon, as the earth-abundant semiconductor, has low cost and good compatibility with mature complementary metal-oxide-semiconductor technology. Therefore, instead of choosing the proper semiconductor with a specific bandgap energy, hyperdoping technique, which can introduce deep-level dopants and intermediate band into silicon, enable silicon to operate in infrared wavebands. Particularly, the hyperdoped silicon with transition metals, having low ionized impurity scatting, makes silicon a promising infrared detection material. In present work, zinc-hyperdoped silicon is fabricated by femtosecond pulsed laser irradiation. The doping concentration of zinc has exceeded 1019 cm−3, and even reached 1022 cm−3, which is about five orders of magnitude greater than the solid solubility of zinc in crystalline Si. The zinc-hyperdoped silicon shows sub-bandgap absorptance of 87.86 % at 1310 nm. Temperature-dependent Hall effect measurements prove that zinc doping results in acceptor energy level located at 0.520 eV above the valence band maximum. It is worth nothing that, zinc-oxygen related defect state results in donor energy level located at 0.252 eV below the conduction band minimum when lower laser fluence is used, which means the energy level of impurity is altered by the presence of undesignedly doped oxygen atoms, suggesting compound formation between the zinc atoms and oxygen atoms.

First principles calculation for N[sbnd]Si co-doping in diamond

The substituted N and NSix (x = 1, 2, 3, 4) complexes in diamond with possible structures are investigated in terms of the structural models, band structures, density of states, formation energies, ionization energies and binding energies by first-principles calculation. For NSix (x = 0, 1, 2) with stable structures, the electron distribution around N dopant is asymmetrical, and donor levels are deep. Meanwhile, the donor level position, the contribution to donor level, ionization energies are almost equal, since the contribution of Si atoms to the donor levels is almost ignorable. However, for the stable structure NSix with x = 3, the N atom is tetracoordinated, and the contribution of Si to the donor energy level increases. The NSi4 structure (Td symmetry is preserved) has a shallow donor level with an ionization energy of 0.35 eV in formation energy method and 0.44 eV in empirical Marker method. In addition, the formation energies and binding energies increase with the increased Si atoms. This work is helpful for understanding the doping features of NSi complexes in diamond.

Spin dynamics of exchange-coupled nitrogen donors in heavily dopedn-type15RSiC monocrystals: Multifrequency EPR and EDMR study

Semiconductor devices based on $15R$ silicon carbide (SiC) show improved properties compared to other polytypes. Here, we report the investigation of nitrogen-doped $15R$ SiC monocrystals with $({N}_{\mathrm{D}}--{N}_{\mathrm{A}})\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3}$ using multifrequency electron paramagnetic resonance (EPR) and electrically detected magnetic resonance (EDMR) spectroscopic methods in the microwave (MW) frequency range from 9.4 to 328.84 GHz and in the temperature range from 4.2 to 300 K. A single intensive $S$ line with $S=1/2$, at ${g}_{\ensuremath{\perp}}=2.0026(2)$, and ${g}_{\ensuremath{\parallel}}=2.0043(2)$ dominates the EPR spectrum in $15R$ SiC at $T<160$ K and was attributed to the exchange-coupled nitrogen (N) donors substituting quasicubic ``$k1$'' site having the deeper energy level in $15R$ SiC lattice. From the analysis of the temperature behavior of the integral intensity, magnetic field position, intensity, shape, and width of the $S$ line, it was concluded that at $T<90$ K, the exchange coupling occurs between localized donor electrons, while at $T=90\ensuremath{-}150$ K the interaction between exchange-coupled N donors and conduction electrons takes place. In the temperature interval from 20 to 160 K, the $S$-line EPR width was characterized by a two-phonon Orbach relaxation process with the activation energy of $\ensuremath{\sim}6.5$ meV corresponding to the valley-orbit splitting values for N donors in $15R$ SiC. The variable-range hopping regime obeying the ${T}^{1/4}$ law was found to take place at $T<20$ K leading to the appearance of the $S$ line in the EDMR spectrum at low temperatures. The appearance of the EDMR signal from exchange-coupled N donors is caused by the EPR-induced temperature-increase mechanism and the spin-flip hops process. The results obtained from MW conductivity measurements agree with EPR and EDMR data. The temperature variation of MW conductivity was described by several processes, including the electron-hopping process between N donor impurity atoms at $T<50$ K with activation energy ${\ensuremath{\varepsilon}}_{3}=1.5$ meV, electron transitions between Hubbard bands at $T=50--100$ K; the transition of the electrons from the donor energy levels to conduction band with ionization energy ${\ensuremath{\varepsilon}}_{1}=32$ meV at $T=100--200$ K and scattering of the conduction electrons by ionized donors occurred at the temperature higher than 200 K.

Determination of CN deep donor level in p-GaN with heavy Mg doping via a carrier statistics approach

An equilibrium carrier statistics approach with a partial ionization model is proposed to determine the energy level of CN deep donors in p-type GaN with heavy Mg doping. Unlike usual compensating centers that are assumed to be fully ionized under equilibrium, partial ionization of the CN donor was taken into consideration. The energy level of the CN donor is determined to be EV + (0.20 ± 0.01) eV at elevated temperatures (∼350 K) using such a partial ionization model. The donor level for an isolated C center at a low temperature limit is further calculated considering the doping and temperature effects, which is EV + (0.32 ± 0.01) eV. Furthermore, the ionization ratio of CN is found to be dependent on the C concentration and can then be estimated to be in the range of 0.3–0.8. Such a partial ionization characteristic of CN may capture/emit free carriers during device operation and should be taken into account when analyzing device reliability.

Long-Lived Multiple Charge Separation by Proton-Coupled Electron Transfer.

Multiple charge separation has been successfully realized by a proton-coupled electron transfer reaction in an organic cocrystal. Benefiting from the adjustable electronic energy level of the electron donor and acceptor through thermal-induced proton migration, distinct optical absorption behaviors combined with color changes to blue or green are observed in these charge-separated states. It is of interest to note that such charge-separated states exhibit a longer lifetime of over a month as a result of the excellent coplanarity and π-π interaction of the electron acceptors. Moreover, the enhanced absorption toward longer wavelengths endows the charge-separated state with near-infrared (808 nm) photothermal conversion for imaging and bacterial inhibition, whereby the conversion performance can be controlled by the degree of proton migration.