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Trap states in semiconductors usually degrade charge separation and collection in photovoltaics due to trap-mediated nonradiative recombination. Here, it is found that perovskite can be heavily doped in low concentration with non-ignorable broadband infrared absorption in thick films and their trap states accumulate electrons through infrared excitation and hot carrier cooling. A hybrid one-sided abrupt perovskite/TiO2 p-N heterojunction is demonstrated that enables partial collection of these trap-filled charges through a tunneling process instead of detrimental recombination. The tunneling is from broadband trap states in the wide depleted p-type perovskite, across the barrier of the narrow depleted TiO2 region (<5 nm), to the N-type TiO2 electrode. The trap states inject carriers into TiO2 through tunneling and produce around-unity peak external quantum efficiency, giving rise to near-infrared photovoltaics. The near-infrared response allows photodetecting devices to work in both diode and conductor modes. This work opens a new avenue to explore the near-infrared application of hybrid perovskites. [ABSTRACT FROM AUTHOR]

Carbon-based hole transport material (HTM)-free perovskite solar cells (PSCs) have shown much promise for practical applications because of their high stability and low cost. However, the efficiencies of this kind of PSCs are still relatively low, especially for the simplest paintable carbon-based PSCs, in comparison with the organic HTM-based PSCs. This can be imputed to the perovskite deposition methods that are not very suitable for this kind of devices. A solvent engineering strategy based on two-step sequential method is exploited to prepare a high-quality perovskite layer for the paintable carbon-based PSCs in which the solvent for CH3NH3I (MAI) solution at the second step is changed from isopropanol (IPA) to a mixed solvent of IPA/Cyclohexane (CYHEX). This mixed solvent not only accelerates the conversion of PbI2 to CH3NH3PbI3 but also suppresses the Ostwald ripening process resulting in a high-quality perovskite layer, e.g., pure phase, even surface, and compact capping layer. The paintable carbon-based PSCs fabricated from IPA/CYHEX solvent exhibits a considerable enhancement in photovoltaic performance and performance reproducibility in comparison with that from pure IPA, especially on fill factor (FF), owing mainly to the better contact of perovskite/carbon interface, lower trap density in perovskite, higher light absorption ability, and faster charge transport of perovskite layer. As a result, the highest power conversion efficiency (PCE) of 14.38% is obtained, which is a record value for carbon-based HTM-free PSCs. Furthermore, a PCE of as high as 10% is achieved for the large area device (1 cm2), also the highest of its kind. [ABSTRACT FROM AUTHOR]

Multimode luminescence relates to how charge carriers are transported and recombined in response to various physical excitations. It shows promising applications in many fields like advanced anti‐counterfeiting, information storage and encryption. Enabling a stable single compound with multimode luminescence is a unique technology but still remains a challenge. Herein, a versatile and high‐performance energy storage LiTaO3:0.01Tb3+,xGd3+ perovskite is discovered by utilizing the interplay of electron‐trapping defect levels and hole‐trapping Tb3+. It combines an excellent charge carrier storage capacity (≈7 and 12 times higher than state‐of‐the‐art BaFBr(I):Eu2+ and Al2O3:C), >1200 h storage duration, >40 h afterglow, efficient optically stimulated luminescence, persistent mechanoluminescence, and force‐induced charge carrier storage features. Particularly, it well responds to various stimuli channels, i.e., wide‐range X‐rays to 850 nm infrared photons, thermal activation, mechanical force grinding, or compression. To elucidate this multimode luminescence, charge carrier trapping and release processes in LiTaO3:0.01Tb3+,xGd3+ with various physical stimulations will be unraveled by combining the vacuum‐referred binding diagram construction, spectroscopy, thermoluminescence, and mechanoluminescence techniques. The versatile and high‐performance LiTaO3:0.01Tb3+,xGd3+ enables promising proof‐of‐concept multimode luminescence applications in advanced anti‐counterfeiting, flexible X‐ray imaging, continuous compression force sensing, and non‐real‐time recording. [ABSTRACT FROM AUTHOR]

A planar perovskite solar cell that incorporates a nanocarbon hole-extraction layer is demonstrated for the first time by an inkjet printing technique with a precisely controlled pattern and interface. By designing the carbon plus CH3NH3I ink to transform PbI2 in situ to CH3NH3PbI3, an interpenetrating seamless interface between the CH3NH3PbI3 active layer and the carbon hole-extraction electrode was instantly constructed, with a markedly reduced charge recombination compared to that with the carbon ink alone. As a result, a considerably higher power conversion efficiency up to 11.60 % was delivered by the corresponding solar cell. This method provides a major step towards the fabrication of low-cost, large-scale, metal-electrode-free but still highly efficient perovskite solar cells. [ABSTRACT FROM AUTHOR]

A planar perovskite solar cell that incorporates a nanocarbon hole-extraction layer is demonstrated for the first time by an inkjet printing technique with a precisely controlled pattern and interface. By designing the carbon plus CH3NH3I ink to transform PbI2 in situ to CH3NH3PbI3, an interpenetrating seamless interface between the CH3NH3PbI3 active layer and the carbon hole-extraction electrode was instantly constructed, with a markedly reduced charge recombination compared to that with the carbon ink alone. As a result, a considerably higher power conversion efficiency up to 11.60 % was delivered by the corresponding solar cell. This method provides a major step towards the fabrication of low-cost, large-scale, metal-electrode-free but still highly efficient perovskite solar cells. [ABSTRACT FROM AUTHOR]

Metal mixed‐halide perovskite has demonstrated considerable potential in the development of solution‐treated blue light‐emitting diodes (LEDs) with high external quantum efficiency, excellent color purity, and tunable wavelength. However, the severe phase segregation of mixed‐halide perovskite under bias voltage would lead to the spectral instability of LEDs. Therefore, suppressing phase segregation of Br/Cl perovskite towards spectrally stable blue perovskite LEDs (PeLEDs) is a big challenge. In this work, we systematically explore the influence of perovskite component, preparation conditions, and device structures on the spectral stability of PeLEDs. We have observed that the stable spectra increased the proportion of Cs in the A‐site cations, passivator, and the annealing temperature of perovskite films. Finally, we achieve a spectra‐stable and high‐performance blue PeLED under optimized conditions. Our findings provide important guidance for preparing spectrally stable PeLEDs. [ABSTRACT FROM AUTHOR]

Sputtering nickel oxide (NiOx) is a production‐line‐compatible route for depositing hole transport layers (HTL) in perovskite/silicon tandem solar cells. However, this technique often results in films with low crystallinity and structural flaws, which can impair electronic conductivity. Additionally, the complex surface chemistry and inadequate Ni3+/Ni2+ ratio impede the effective binding of self‐assembled monolayers (SAMs), affecting hole extraction at the perovskite/HTL interface. Herein, these issues are addressed using a recrystallization strategy by treating sputtered NiOx thin films with sodium periodate (NaIO4), an industrially available oxidant. This treatment improved crystallinity and increased the Ni3+/Ni2+ ratio, resulting in a higher content of nickel oxyhydroxide. These enhancements strengthened the SAM's anchoring capability on NiOx and improved the hole extraction at the perovskite/HTL interface. Moreover, the NaIO4 treatment facilitated Na+ diffusion within the perovskite layer and minimized phase separation, thus improving device stability. As a result, single‐junction perovskite solar cells with a 1.68 eV bandgap achieve a power conversion efficiency (PCE) of 23.22% for an area of 0.12 cm2. Perovskite/silicon tandem cells with an area of 1 cm2 reached a PCE of 30.48%. Encapsulated tandem devices retained 95% of their initial PCE after 300 h of maximum power point tracking under 1‐sun illumination at 25 °C. [ABSTRACT FROM AUTHOR]

A stable and compact fullerene electron transport layer (ETL) is crucial for high‐performance inverted perovskite solar cells (PSCs). However, traditional fullerene‐based ETLs like C60 and PCBM are prone to aggregate under operational conditions, a challenge recently recognized by academic and industrial researchers. Here, we designed and synthesized a novel cross‐linkable fullerene molecule, bis((3‐methyloxetan‐3‐yl)methyl) malonate‐C60 monoadduct (BCM), for use as an ETL in PSCs. Upon a low‐temperature annealing at 100 °C, BCM undergoes in situ cross‐linking to form a robust cross‐linked BCM (CBCM) film, which demonstrates excellent electron mobility and a suitable band structure for efficient PSCs. Our results show that PSCs incorporating CBCM‐based ETL achieve an impressive efficiency of 25.89 % (certified: 25.36 %), significantly surpassing the 23.25 % efficiency of PCBM‐based devices. The intramolecular covalent interactions within CBCM films effectively prevent aggregation and enhance film compactness, creating an internal encapsulation layer that mitigates the decomposition and ion migration of perovskite components. Consequently, CBCM‐based PSCs show exceptional stability, maintaining 97.8 % of their initial efficiency after 1000 hours of maximum power point tracking, compared to only 78.6 % retention in PCBM‐based devices after less than 820 hours. [ABSTRACT FROM AUTHOR]

Discovering bismuth based smart materials that can respond to thermal, mechanical, and wide range X-ray to infrared photon excitation remains a challenge. Such materials have various uses like in advanced information encryption. In this work, valence state change between Bi2+, Bi3+, and Bi4+, and the dual role of Bi3+ in trapping electrons and holes have been studied in Bi3+ or/and Ln3+ (Ln=Tb or Pr) doped LiScGeO 4 family of compounds by vacuum referred binding energy (VRBE) diagram construction, thermoluminescence, and spectroscopy. Electron release from Bi2+ has been evidenced. It can be used to experimentally determine the VRBE in the Bi2+ 2P 1/2 ground state and to realize Bi3+ negative quenching luminescence. Particularly, a new force induced charge carrier storage phenomenon has been discovered for non-real-time force recording. Wide range of emission tailorable afterglow, unique Bi3+ ultraviolet-A, white, and infrared afterglow have been demonstrated by using Bi3+ as a hole trapping and recombination center and using energy transfer processes from Bi3+ to Tb3+, Pr3+, Dy3+, or Cr3+. Proof-of-concept advanced anti-counterfeiting, information encryption, and X-ray imaging will be demonstrated. This work not only develops smart storage phosphors, but more importantly unravels the valence change between Bi2+, Bi3+, or Bi4+ and how it can affect the trapping and release of charge carriers with thermal, optical, or mechanical excitation. This work therefore can promote the discovery and development of Bi3+ based smart materials for various applications. Discovering bismuth based smart materials that can respond to thermal, mechanical, and wide range X-ray to infrared photon excitation remains a challenge. Such materials have various uses like in advanced information encryption. In this work, valence state change between Bi2+, Bi3+, and Bi4+, and the dual role of Bi3+ in trapping electrons and holes have been studied in Bi3+ or/and Ln3+ (Ln=Tb or Pr) doped LiScGeO 4 family of compounds by vacuum referred binding energy (VRBE) diagram construction, thermoluminescence, and spectroscopy. Electron release from Bi2+ has been evidenced. [Display omitted] [ABSTRACT FROM AUTHOR]

Designing an efficient modification molecule to mitigate non‐radiative recombination at the NiOx/perovskite interface and improve perovskite quality represents a challenging yet crucial endeavor for achieving high‐performance inverted perovskite solar cells (PSCs). Herein, we synthesized a novel fullerene‐based hole transport molecule, designated as FHTM, by integrating C60 with 12 carbazole‐based moieties, and applied it as a modification molecule at the NiOx/perovskite interface. The in situ self‐doping effect, triggered by electron transfer between carbazole‐based moiety and C60 within the FHTM molecule, along with the extended π conjugated moiety of carbazole groups, significantly enhances FHTM's hole mobility. Coupled with optimized energy level alignment and enhanced interface interactions, the FHTM significantly enhances hole extraction and transport in corresponding devices. Additionally, the introduced FHTM efficiently promotes homogeneous nucleation of perovskite, resulting in high‐quality perovskite films. These combined improvements led to the FHTM‐based PSCs yielding a champion efficiency of 25.58 % (Certified: 25.04 %), notably surpassing that of the control device (20.91 %). Furthermore, the unencapsulated device maintained 93 % of its initial efficiency after 1000 hours of maximum power point tracking under continuous one‐sun illumination. This study highlights the potential of functionalized fullerenes as hole transport materials, opening up new avenues for their application in the field of PSCs. [ABSTRACT FROM AUTHOR]

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]

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]

Deposition of a passivation layer on top of the perovskite is proven to be an effective method for improving the efficiency and long‐term stability of perovskite solar cells (PSCs). And the spin‐coating method is the most typical and popular method developed for this purpose. However, the spin‐coating method wastes substantial passivator materials, thus the quantitative relationship between the passivator amount and the device performance cannot be obtained. Herein, a quantitative deposition method is developed through drop‐on‐demand inkjet printing to investigate the influence of 2‐adamantylamine hydrochloride (2‐ADAHCl) deposition surface density on the device performance, which is found to have a significant impact on the device performance. A low deposition surface density of 1.1 µg cm−2 does not reach its optimum passivation capability. In contrast, an excess deposition surface density of 10.1 µg cm−2 would lead to energy level mismatch and large series resistance at the perovskite/hole transport layer (HTL) interface, thus resulting in inferior device properties. At an optimum deposition surface density of 2.5 µg cm−2, perovskite surface defects are greatly suppressed, and the interfacial contact between perovskite and HTL is improved. Finally, PSCs with a high efficiency of 24.57% are achieved with improved operational and environmental stabilities. [ABSTRACT FROM AUTHOR]

Se‐functionalized small molecule acceptors (SMAs) exhibit unique advantages in constructing materials with near‐infrared absorption, but their photovoltaic performance lags behind that of S‐containing analogs in organic solar cells (OSCs). Herein, two new Se‐containing SMAs, namely Se‐EH and Se‐EHp, are designed and synthesized by regulating bifurcation site of outer alkyl chain, which enables Se‐EH and Se‐EHp to form different 3D crystal frameworks from CH1007. Se‐EH displays tighter π–π stacking and denser packing framework with smaller‐sized pore structure induced by larger steric hindrance effect of outer alkyl chain branched at 2‐position, and a higher dielectric constant of PM6:Se‐EH active layer can be obtained. OSCs based on PM6:Se‐EH achieved very high PCEs of 18.58% in binary and 19.03% in ternary devices with a high FF approaching 80% for Se‐containing SMAs. A more significant alkyl chain steric hindrance effect in Se‐EH adjusts the molecular crystallization to form a favorable nanofiber interpenetrating network with an appropriate domain size to reduce rate of sub‐ns recombination and promote balanced transport of carriers. This work provides references for further design and development of highly efficient Se‐functionalized SMAs. [ABSTRACT FROM AUTHOR]

Tin‐based perovskite solar cells (TPSCs) have received increasing attention due to their low toxicity, high theoretical efficiency, and potential applications as wearable devices. However, the inherent fast and uncontrollable crystallization process of tin‐based perovskites results in high defect density in the film. Meanwhile, when fabricated into flexible devices, the prepared perovskite film exhibits inevitable brittleness and high Young's modulus, seriously weakening the mechanical stability. In this work, we design and synthesize a cross‐linkable fullerene, thioctic acid functionalized C60 fulleropyrrolidinium iodide (FTAI), which has multiple interactions with perovskite components and can finely regulate the crystallization quality of perovskite film. The obtained perovskite film shows an increased grain size and a more matched energy level with the electron transport material, effectively improving the carrier extraction efficiency. The FTAI‐based rigid device achieves a champion efficiency of 14.91 % with enhanced stability. More importantly, the FTAI located at the perovskite grain boundaries could spontaneously cross‐link during the perovskite annealing process, which effectively improves the conductivity and elasticity of grain boundaries, thereby giving the film excellent bending resistance. Finally, the FTAI‐based wearable device yields a record efficiency of 12.35 % and displays robust bending durability, retaining about 90 % of the initial efficiency after 10,000 bending times. [ABSTRACT FROM AUTHOR]

Tin‐based perovskite solar cells (TPSCs) have received increasing attention due to their low toxicity, high theoretical efficiency, and potential applications as wearable devices. However, the inherent fast and uncontrollable crystallization process of tin‐based perovskites results in high defect density in the film. Meanwhile, when fabricated into flexible devices, the prepared perovskite film exhibits inevitable brittleness and high Young's modulus, seriously weakening the mechanical stability. In this work, we design and synthesize a cross‐linkable fullerene, thioctic acid functionalized C60 fulleropyrrolidinium iodide (FTAI), which has multiple interactions with perovskite components and can finely regulate the crystallization quality of perovskite film. The obtained perovskite film shows an increased grain size and a more matched energy level with the electron transport material, effectively improving the carrier extraction efficiency. The FTAI‐based rigid device achieves a champion efficiency of 14.91 % with enhanced stability. More importantly, the FTAI located at the perovskite grain boundaries could spontaneously cross‐link during the perovskite annealing process, which effectively improves the conductivity and elasticity of grain boundaries, thereby giving the film excellent bending resistance. Finally, the FTAI‐based wearable device yields a record efficiency of 12.35 % and displays robust bending durability, retaining about 90 % of the initial efficiency after 10,000 bending times. [ABSTRACT FROM AUTHOR]

Recently, lead‐free Sn‐based perovskite light‐emitting diodes (PeLEDs) have attracted wide attention due to their near‐infrared emission and environmental friendliness. However, desired Sn2+ is easily oxidized to Sn4+ in the crystallization process, resulting in defects and intrinsically p‐doped properties in the perovskite films. The uncontrollable oxidation affects the charge injection balance and radiative recombination, leading to poor device performance. Herein, a bi‐functional conductive molecular, 2,7‐bis(diphenylphosphoryl)‐9,9′‐spirobifluorene (SPPO13) with two P═O functional groups, is used to interact with perovskite to passivate defects and suppress the oxidation of Sn2+. Moreover, the SPPO13 modification layer inserted between the perovskite emitter and the electron transport layer can regulate the carrier injection and transport, thus promoting the charge balance. As a result, the high‐performance near‐infrared CsSnI3 PeLEDs with a record external quantum efficiency (EQE) of 6.60% and ultra‐low efficiency roll‐off are achieved. The work provides a novel approach to regulate defect passivation and charge transport for efficient Sn‐based PeLEDs. [ABSTRACT FROM AUTHOR]

Metal halide perovskite light‐emitting diodes (Pero‐LEDs) have gained great attention due to their promising applications in lighting and displays. However, in their conventional three‐layered sandwich structure, some undeserved carrier behaviors, such as imbalanced carrier injection, severe carrier loss, and unstable recombination zone, limit the device's performance. Herein, a four‐layered design by inserting a nickel acetate (Ni(OAc)2) interlayer between the emitter and hole‐transport layer(HTL) to manage carrier behavior and improve radiative recombination efficiency is proposed. Specifically, the Ni(OAc)2 interlayer is poorly conductive and can partially block the hole injection, making the hole‐electron injection more balanced. And the Ni(OAc)2 interlayer avoids the direct contact between the perovskite emitter and hole transporter, reducing the interfacial carrier quenching. Moreover, the Ni(OAc)2 interlayer inhibits the electron‐migrated recombination at the hole transporter interface, confining the carrier recombination zone in the emitter layer. As a result, the corresponding Pero‐LEDs achieve a maximum external quantum efficiency (EQEmax) of 24.6% with good reproducibility, showing an average EQEmax of over 20%. [ABSTRACT FROM AUTHOR]

Perovskite films prepared by the solution process usually result in irregular grain orientation and rich buried interface defects, hindering the further improvement of device performance. Herein, multi‐fluorine‐containing C60‐ and C70 (higher fullerene)‐porphyrin derivatives, F60PD and F70PD, are synthesized and pre‐buried to modify the SnO2/perovskite heterointerface. The F70PD modification layer provides a better perovskite quality and more effective electron transporting capability compared to the corresponding F60PD, with the F70PD being more effective in regulating the perovskite growth, passivating the buried interface defects, and optimizing the interface energy level alignment. Consequently, the F70PD‐based device delivers superior efficiency and stability than the control and F60PD‐based devices. The F70PD‐based device yields a champion efficiency of 24.09% with negligible hysteresis. Meanwhile, due to the increased activation energy of ion migration, the F70PD‐based device maintains 80% of its initial efficiency after operating at the maximum power point for 1620 h. This study highlights the potential of designing higher fullerene materials for buried interface to further improve the perovskite solar cells' performance. [ABSTRACT FROM AUTHOR]

The non‐radiative recombination at the interfaces of perovskite solar cells (PSCs) is a crucial issue that limits the efficiency and stability of the devices. State‐of‐the‐art surface passivation strategies usually utilize alkyl ammonium halides to suppress the non‐radiative recombination of PSCs, but their high surface reactivity leads to the transformation into 2D perovskites under working conditions, limiting the passivation effect and the charge transport of PSCs. Herein, a non‐halide ionic salt 1‐naphthylmethylammonium formate (NMACOOH) is synthesized for surface passivation of perovskite films. In contrast to the traditional 1‐naphthylmethylammonium iodide, NMACOOH treatment hinders the formation of 2D perovskite and forms a thermally stable PbI2‐NMACOOH adduct on the perovskite surface. Surface characterization reveals that NMA+ can passivate the cation vacancies of the 3D perovskite while HCOO− passivates the metallic Pb0 and halide‐vacancy defects. Therefore, the non‐radiative recombination of PSCs is dramatically suppressed and a high open‐circuit voltage of 1.19 V is obtained. Finally, PSCs with high efficiency of 24.75% and improved long‐term stability (98% of the initial efficiency after 1800‐h storage) are obtained. Moreover, the NMACOOH‐passivated devices also show robust operational stability, retaining 83% of the initial efficiency after working for 658 h under continuous one‐sun illumination. [ABSTRACT FROM AUTHOR]

Developing X-ray charged dosimeters with excellent charge carrier storage capacity and stability is challenging. Such energy storage dosimeters have fascinating use in developing novel applications, for instance, in radiation detection, advanced multimode anti-counterfeiting, and flexible X-ray imaging of curved objects. Herein, novel LiTaO 3 :Ln3+,Eu3+ (Ln=Tb or Pr) perovskite dosimeters are developed by combining the vacuum referred binding energy (VRBE) diagram of LiTaO 3 and the optimization of dopant's concentration and compound synthesis condition. [Display omitted] • Eu3+ was evidenced as a good electron trapping centre. • Excellent LiTaO 3 :Ln3+,Eu3+ (Ln = Tb or Pr) dosimeters were rationally developed. • Charge carriers can be stored more than 1000 h. • New and advanced X-ray imaging application for curved objects was realized. • Promising and advanced anti-counterfeiting applications were demonstrated. Developing X-ray charged dosimeters with excellent charge carrier storage capacity and stability is challenging. Such energy storage dosimeters have fascinating use in developing novel applications, for instance, in radiation detection, advanced multimode anti-counterfeiting, and flexible X-ray imaging of curved objects. Herein, novel LiTaO 3 :Ln3+,Eu3+ (Ln = Tb or Pr) perovskite dosimeters are reported by combining the vacuum referred binding energy (VRBE) diagram of LiTaO 3 and the optimization of dopant's concentration and compound synthesis condition. Based on the VRBE diagram prediction, charge carrier capturing and de-trapping processes in Eu3+ and/or Ln3+ (Ln = Tb or Pr) doped LiTaO 3 will be studied to unravel the role of Eu3+ as a good electron trapping centre and to discover a record storage phosphor. The ratios of the thermoluminescence intensity of the optimized LiTaO 3 :0.005Tb3+,0.001Eu3+ to that of the state-of-the-art BaFBr(I):Eu2+, Al 2 O 3 :C, or NaLuF 4 :Tb3+ are 5.2, 8.8, or 2.8, respectively. The charge carriers can be stored more than 1000 h in LiTaO 3 :0.005Tb3+,0.001Eu3+. Proof-of-concept anti-counterfeiting application will be demonstrated by combining the colour-tailorable photoluminescence, afterglow, thermally, or optically stimulated luminescence in LiTaO 3 :0.005Tb3+,xEu3+ and LiTaO 3 :0.005Pr3+,0.001Eu3+. Multimode anti-counterfeiting application will be proposed by combining a high absolute X-ray scintillation light yield of 19000 ± 1800 ph/MeV of LiTaO 3 :0.005Tb3+,0.001Eu3+. Proof-of-concept flexible X-ray imaging application will be demonstrated by using the optimized LiTaO 3 :0.005Tb3+, 0.001Eu3+ dispersed in a silicone gel film. [ABSTRACT FROM AUTHOR]

Highlights: The modification of perovskite precursor by a series of phosphoryl chloride molecules can indeed improve the performance of perovskite LEDs (Pero-LEDs). The bis(2-oxo-3-oxazolidinyl) phosphinic chloride can not only regulate the phase distribution by controlling the crystallization rate but also passivate the defects of the quasi-2D perovskite. Highly efficient and reproducible Pero-LEDs are achieved with an maximum external quantum efficiency (EQEmax) of 20.82% and an average EQE (EQEave) of around 20% on 50 devices. Quasi-2D perovskites have attracted tremendous interest for application as light-emission layers in light-emitting diodes (LEDs). However, the heterogeneous n phase and non-uniform distribution still severely limit the further development of quasi-2D perovskite LEDs (Pero-LEDs). Meanwhile, the increased defect density caused by the reduced dimension and grain size induces non-radiative recombination and further deteriorates the device performance. Here, we found that a series of molecules containing phosphoryl chloride functional groups have noticeable enhancement effects on the device performance of quasi-2D Pero-LEDs. Then, we studied the modification mechanism by focusing on the bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOPCl). It is concluded that the BOPCl can not only regulate the phase distribution by decreasing the crystallization rate but also remain in the grain boundaries and passivate the defects. As a result, the corresponding quasi-2D Pero-LEDs obtained a maximum external quantum efficiency (EQEmax) of 20.82% and an average EQE (EQEave) of around 20% on the optimal 50 devices, proving excellent reproducibility. Our work provides a new selection of molecular types for regulating the crystallization and passivating the defects of quasi-2D perovskite films. [ABSTRACT FROM AUTHOR]

Highlights: Three bulky cation chlorides (PMACl, PEACl and NMACl) are used to modify the perovskite surface and form pure-anion 2D (PMA)2PbCl4, mixed-anion 2D (PEA)2Pb(IxCl4-x), and non-2D NMAI passivation layers, respectively. Intermolecular interactions between the bulky cations and the strength of cation-halide hydrogen bonds are critical to forming the three distinct passivation layers. Semi-transparent wide-bandgap perovskite solar cells (WBG-PSCs) with ITO as the back electrode show hysteresis-free PCE of 18.60% and VOC deficit of 0.49 V. Wide-bandgap (WBG) perovskite solar cells suffer from severe non-radiative recombination and exhibit relatively large open-circuit voltage (VOC) deficits, limiting their photovoltaic performance. Here, we address these issues by in-situ forming a well-defined 2D perovskite (PMA)2PbCl4 (phenmethylammonium is referred to as PMA) passivation layer on top of the WBG active layer. The 2D layer with highly pure dimensionality and halide components is realized by intentionally tailoring the side-chain substituent at the aryl ring of the post-treatment reagent. First-principle calculation and single-crystal X-ray diffraction results reveal that weak intermolecular interactions between bulky PMA cations and relatively low cation-halide hydrogen bonding strength are crucial in forming the well-defined 2D phase. The (PMA)2PbCl4 forms improved type-I energy level alignment with the WBG perovskite, reducing the electron recombination at the perovskite/hole-transport-layer interface. Applying this strategy in fabricating semi-transparent WBG perovskite solar cells (indium tin oxide as the back electrode), the VOC deficits can be reduced to 0.49 V, comparable with the reported state-of-the-art WBG perovskite solar cells using metal electrodes. Consequently, we obtain hysteresis-free 18.60%-efficient WBG perovskite solar cells with a high VOC of 1.23 V. [ABSTRACT FROM AUTHOR]

Interfacial defects are one of the main origins of the hysteresis effect and limit the efficiency and light stability of perovskite solar cells (PSCs). Herein, the authors propose to grant the hole‐transport materials' (HTMs) improved isotropic coordination and defect passivation through simple halogenation, enabling a robust perovskite/hole‐transport layer interface while avoiding the use of an external passivation layer. First‐principles simulations and experimental results show that the halogenated HTMs offer more isotropic coordination sites for Pb2+ ions than the halogen‐free ones, thus providing the enhanced passivating ability of defects regardless of their molecular orientation at the surface of perovskite films. Consequently, the PSCs based on the chlorinated spiro[fluorene‐9,9′‐xanthene]‐based HTM show suppressed nonradiative recombination, delivering a remarkable open‐circuit voltage (VOC) enhancement (from 1.07 to 1.14 V) and a minimal hysteresis index of as low as 0.07%. The corresponding cells also show much improved light stability, retaining 81% of the initial efficiency after 1000 h of continuous illumination at the maximum power point. This work demonstrates that a solid isotropic coordination capability of HTMs with Pb2+ is critical to forming a robust interface and improving the PSCs' light stability. [ABSTRACT FROM AUTHOR]

Pyrite (FeS 2 ) stands out from other metal sulfides due to its abundance, low toxicity and high specific energy density. However, the low utilization and short cycle life of FeS 2 caused by irreversible side reactions and dramatic structural changes during charge/discharge process seriously hinders its practical application. In this work, we designed FeS 2 nanochains to address these issues because this unique structure not only shortens the ion/electron diffusion distance, increases the electrode/electrolyte contact area, but also accommodates the strain associated with Li ion intercalation and deintercalation reactions. Compared with nanoparticles, the FeS 2 nanochains synthesized by magnetic - field - assisted aerosol pyrolysis could cycle up to 800 cycles at 0.5C, remained a discharge capacity of 342.4 mA h g −1 in the voltage range of 1.0 - 2.6 V and achieved a remarkable capacity fading rate of 0.02% per cycle, which is among the best values demonstrated so far for Li/FeS 2 cells. In - situ Raman experiments revealed that the irreversible side reactions could be suppressed through controlling the voltage window, which can be benefit for further improving the performance of Li/FeS 2 cells. [ABSTRACT FROM AUTHOR]

Developing X‐ray or UV‐light charged storage and mechanoluminescence (ML) materials with high charge carrier storage capacity is challenging. Such materials have promising utilization in developing new applications, for example, in flexible X‐ray imaging, stress sensing, or non‐real‐time recording. Herein, the study reports on such materials; Bi3+, Tb3+, Ga3+, or Ge4+ doped LiTaO3 perovskite storage and ML phosphors. Their photoluminescence, thermoluminescence (TL), and ML properties are studied. The charge carrier trapping and release processes in the Bi3+, Tb3+, Ga3+, or Ge4+ doped LiTaO3 are explained by using the constructed vacuum referred binding energy diagram of LiTaO3 including the energy level locations of unintended defects, Tb3+, Bi3+, and Bi2+. The ratio of the TL intensity after X‐ray charging of the optimized LiTaO3:0.005Bi3+,0.006Tb3+,0.05Ga3+, or LiTaO3:0.005Bi3+,0.006Tb3+,0.05Ge4+ to that of the state‐of‐the‐art BaFBr(I):Eu2+ is ≈1.2 and 2.7, respectively. Force induced charge carrier storage phenomena is studied in the Tb3+, Bi3+, Ga3+, or Ge4+ doped LiTaO3. Proof‐of‐concept compression force distribution sensing and X‐ray imaging is demonstrated by using optimized LiTaO3:0.005Bi3+,0.006Tb3+,0.05Ga3+ dispersed in a hard epoxy resin disc and in a silicone gel film. Proof‐of‐concept color‐tailorable ML for anti‐counterfeiting is demonstrated by admixing commercial ZnS:Cu+,Mn2+ with optimized LiTaO3:0.005Bi3+,0.006Tb3+,0.05Ge4+ in an epoxy resin disc. [ABSTRACT FROM AUTHOR]

The under‐coordinated defects within perovskite and its relevant interfaces always attract and trap the free carriers via the electrostatic force, significantly limiting the charge extraction efficiency and the intrinsic stability of perovskite solar cells (PSCs). Herein, self‐diffusion interfacial doping by using ionic potassium L‐aspartate (PL‐A) is first reported to restrain the carrier trap induced recombination via the reconstruction of energy level structure at SnO2/perovskite interface in conventional n‐i‐p structured PSCs. Experiments and theories are consistent with the PL‐A anions that can remain at the SnO2 surface due to strong chemical adsorption. During the spin‐coating of the perovskite film, the cations gradually diffuse into perovskite and endow an n‐doping effect, which provides higher force and a better energy level alignment for the carrier transport. As a result, they obtained 23.74% power conversion efficiency for the PL‐A modified small‐area devices, with dramatically improved open‐circuit voltage of 1.19 V. The corresponding large‐area devices (1.05 cm2) achieved an efficiency of 22.23%. Furthermore, the modified devices exhibited negligible hysteresis and enhanced ambient air stability exceeding 1500 h. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting diodes (Pero‐LEDs) with external quantum efficiencies (EQEs) of over 20% have been achieved in the last several years. However, the reproducibility of such high‐efficiency Pero‐LEDs is still low. The perovskite film quality, especially for the non‐radiative defects, is crucial in determining the device performance. These defects may lie in bulk grains, grain boundaries, and interfaces of the as‐formed perovskite films. Here, a polymer infiltrative treatment method is developed to realize effective and universal defect passivation. Specifically, poly(vinylidene fluoride) (PVDF) polymer chains are blended into the perovskite films before they are fully crystallizing. This infiltrative treatment method can regulate crystallization and passivate defects through the chemical interactions of perovskite lattices and PVDF. As a result, high‐quality perovskite films with void‐free surfaces and few‐defect crystals are obtianed. The corresponding Pero‐LEDs show a maximum EQE of 22.29% and an average EQE of 20.44 ± 0.73% based on a statistical analysis of 50 devices, exhibiting excellent reproducibility. The work provides better insights into controlling crystal growth and defect passivation via polymer‐assisted methods for efficient Pero‐LEDs. [ABSTRACT FROM AUTHOR]

To date, organic–inorganic hybrid perovskite solar cells (PSCs) have reached a certified efficiency of 25.7%, showing great potential in upscale industrial commercialization. However, a huge obstacle facing the industrialization of PSCs is the decreased efficiency and long‐term stability when upscaling the device area. To overcome these issues, blade‐coating methods have been developed to fabricate large‐area PSCs due to their capability to deposit uniform large‐area perovskite films. Ink engineering plays an important role in the blade‐coating, especially for crystallinity and defect control. In this review, the blade‐coating method to fabricate large‐area perovskite films is first introduced. Then, the perovskite ink engineering for blade‐coating PSCs is systematically summarized. Specifically, the effects of perovskite composition management and solvent engineering on perovskite film quality are discussed, and recent efforts in additive strategy to passivate perovskite defects are also summarized. Subsequently, recent advances in functional layer ink engineering and fully blade‐coated PSCs are summarized. Moreover, the applications of blade‐coating method in hole transporting material‐free carbon‐based PSCs are discussed. Finally, some suggestions and an outlook on this field are provided to help facilitate highly efficient and stable blade‐coated PSCs. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting diodes (Pero‐LEDs) have attracted significant attention due to their high color purity and solution processing, presenting potential applications for next‐generation solid‐state lighting and displays. Continued materials development has shown that passivating non‐radiative defects can improve device performance. In theory, CsPbBr3&Cs4PbBr6 should be a model emitter for Pero‐LEDs, as its lattice matching provides ideal passivation and efficient exciton confinement. However, the low charge transport of Cs4PbBr6 has so far hindered device performance. Herein, a dual‐phase regulation method to grow a CsPbBr3&Cs4PbBr6 perovskite layer that enables efficient electrical injection is developed. This leads to the realization that Pero‐LEDs with a maximum EQE of 22.3% with a luminance of 10,050 cd m−2, and the devices show a T50 of 59 h at 130 cd m−2. [ABSTRACT FROM AUTHOR]

Designing functional fullerenes with roles beyond defect passivation and electron‐transporting for perovskite solar cells (PSCs) is essential to the development of fullerenes and PSCs. Here, the authors design and synthesize a functional fullerene, FPD, composed of a C60 cage, a porphyrin ring, and three pentafluorophenyl groups. The structure features of FPD enable it can form chemical interactions with the perovskite lattices. These interactions enhance the defect passivation effect and prevent the decomposition of perovskite under irradiation. As a result, the FPD‐based device yields an improved power conversion efficiency of 23% with substantially enhanced operational stability (T80 > 1500 h). Furthermore, once got damaged, the FPD can prevent lead leakage by forming a stable and water‐insoluble complex (FPD‐Pb). Their findings provide a novel strategy to achieve high‐performance and eco‐friendly PSCs with functional fullerene materials. [ABSTRACT FROM AUTHOR]

Solution‐processed metal halide perovskites have the advantages of a tunable bandgap, excellent charge transport properties, and suitable exciton binding energy. They therefore emerge as promising semiconductors for efficient perovskite solar cells (PSCs) and bright perovskite light‐emitting diodes (PLEDs). In addition, these devices possess a similar planar–heterojunction architecture, thus novel dual‐functional perovskite light‐emitting solar cells (PLESCs) that can realize electrical‐to‐optical and optical‐to‐electrical conversion on one device are developed. To date, high‐performance PLESCs with 17.2% electroluminescence external quantum efficiency and 25.2% power conversion efficiency are achieved using a holistic optimization approach. However, a comprehensive review focusing on dual‐functional PLESCs with discussion on their development and limitations, remains lacking. Herein, the rapid progress in PLESCs, including 0D quantum dot, 2D Ruddlesden–Popper, and 3D bulk perovskite devices, is reviewed. First, the fundamental understanding of the device structure and working principle of PLESCs is overviewed. Second, the state‐of‐the‐art developments for simultaneously achieving high‐efficiency PSCs and PLEDs, focusing on defect passivation, interface optimization, energy level alignment, and dimensional control, are comprehensively summarized. Finally, the authors offer some perspectives for future trends in the development of promising PLESCs, which can provide guidelines for this emerging field. [ABSTRACT FROM AUTHOR]

Solution‐processed metal halide perovskites have the advantages of a tunable bandgap, excellent charge transport properties, and suitable exciton binding energy. They therefore emerge as promising semiconductors for efficient perovskite solar cells (PSCs) and bright perovskite light‐emitting diodes (PLEDs). In addition, these devices possess a similar planar–heterojunction architecture, thus novel dual‐functional perovskite light‐emitting solar cells (PLESCs) that can realize electrical‐to‐optical and optical‐to‐electrical conversion on one device are developed. To date, high‐performance PLESCs with 17.2% electroluminescence external quantum efficiency and 25.2% power conversion efficiency are achieved using a holistic optimization approach. However, a comprehensive review focusing on dual‐functional PLESCs with discussion on their development and limitations, remains lacking. Herein, the rapid progress in PLESCs, including 0D quantum dot, 2D Ruddlesden–Popper, and 3D bulk perovskite devices, is reviewed. First, the fundamental understanding of the device structure and working principle of PLESCs is overviewed. Second, the state‐of‐the‐art developments for simultaneously achieving high‐efficiency PSCs and PLEDs, focusing on defect passivation, interface optimization, energy level alignment, and dimensional control, are comprehensively summarized. Finally, the authors offer some perspectives for future trends in the development of promising PLESCs, which can provide guidelines for this emerging field. [ABSTRACT FROM AUTHOR]

Over the past several years, perovskite‐based luminescent materials and devices have attracted considerable research interest and achieved superior performance, including red/near‐infrared, green, and blue regions. Despite the abundant research progress in the above‐mentioned luminous regions, studies on cyan‐emitting perovskites are still lacking. However, cyan‐emitting perovskite materials are of great importance and have many promising applications, especially for high‐quality lighting and light communication. Herein, the recent research progress on perovskite with cyan emission is summarized, including the preparation methods and improvement on device performance. The preparation strategies are categorized into compositional engineering, dimensional engineering, and size engineering. The corresponding device performance is displayed too. Furthermore, the strategies of performance enhancement and future perspectives are proposed in the end. There is hope that this minireview can trigger more attention to this particular emitting region. [ABSTRACT FROM AUTHOR]

Fullerene-based electron-transporting layers (ETLs) significantly influence the defect passivation and device performance of inverted perovskite solar cells (PSCs). However, the π-cage structures of fullerenes lead to a strong tendency to self-aggregate, which affects the long-term stability of the corresponding PSCs. Experimental results revealed that [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM)-based ETLs exhibit a certain degree of self-aggregation that affects the stability of the device, particularly under continuous irradiation stress. To modulate the aggregation behavior, we replaced a methyl hydrogen of PCBM with a phenyl group to yield [6,6]-phenyl-C 61 -butyric acid benzyl ester (PCBB). As verified through X-ray crystallography, this minor structural modification results in more non-covalent intermolecular interactions, which effectively enhanced the electron-transporting ability of the PCBB-based ETL and led to an efficiency approaching 20%. Notably, the enhanced intermolecular forces of PCBB suppressed its self-aggregation, and the corresponding device showed significantly improved stability, retaining approximately 90% of its initial efficiency after 600 h under one-sun irradiation with maximum power point tracking. These findings provide a viable approach for the design of new fullerene derivatives to tune their intermolecular interactions to suppress self-aggregation within the ETL for high-performance PSCs. [ABSTRACT FROM AUTHOR]

Recently, metal halide perovskite light‐emitting diodes (Pero‐LEDs) have achieved significant improvement in device performance, especially for external quantum efficiency (EQE). And EQE is mostly determined by internal quantum efficiency of the emitting material, charge injection balancing factor (ηc), and light extraction efficiency (LEE) of the device. Herein, an ultrathin poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (UT‐PEDOT:PSS) hole transporter layer is prepared by a water stripping method, and the UT‐PEDOT:PSS can enhance ηc and LEE simultaneously in Pero‐LEDs, mostly due to the improved carrier mobility, more matched energy level alignment, and reduced photon loss. More importantly, the performance enhancement from UT‐PEDOT:PSS is quite universal and applicable in different kinds of Pero‐LEDs. As a result, the EQEs of Pero‐LEDs based on 3D, quasi‐3D, and quasi‐2D perovskites obtain enhancements of 42%, 87%, and 111%, and the corresponding maximum EQE reaches 17.6%, 15.0%, and 6.8%, respectively. [ABSTRACT FROM AUTHOR]

Fullerene derivatives, especially after purposely functionalization, have potential to efficiently passivate interfacial defects between perovskites and electron transport layers. In this work, a fullerene derivative with amine functional group, 2,5‐diphenyl C60 fulleropyrrolidine (DPC60), is synthesized and employed as an interfacial layer between a perovskite and SnO2 in planar perovskite solar cells (PSCs). The cis‐configuration and the specific amine group of DPC60 effectively enhance the chemical interaction between the perovskite and DPC60, promoting the passivation of perovskite defects at the interface. The suitable energy level of DPC60 and the improved conductivity of the SnO2/DPC60 film facilitate the electron extraction from the perovskite layer. As a result, PSCs incorporated with DPC60 reach a PCE of 20.4% with high reproducibility, which is much higher than that of the bare SnO2 based devices (18.8%). Furthermore, the hydrophobic DPC60 layer suppresses heterogeneous nucleation and improves the crystallinity of the perovskite film, resulting in better device stability, retaining 82% of its initial efficiency after 200 h of 1 sun continuous irradiation and thermal ageing (55 ± 5 °C). [ABSTRACT FROM AUTHOR]

We systematically review the progress of CsPb(I x Br 1− x) 3 solar cells in four aspects: phase stability, crystallization control, low-temperature preparation, and defect passivation. We propose challenges and future directions for developing highly efficient and stable devices. Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(I x Br 1− x) 3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(I x Br 1− x) 3 solar cells and outline possible directions to further improve the device performance. [ABSTRACT FROM AUTHOR]

Although it usually involves troublesome and time-consuming synthesis work, molecular structure tailoring has been the mainstream tool to adjust the optical absorption and bandgap of organic semiconductors. Herein, we provided a convenient and feasible method to prepare narrow bandgap small-molecule semiconductors by Lewis acid-base chemistry and the optical absorption was adjusted by the stoichiometry of Lewis acid-base reactions. In this work, three pyridine capped diketopyrrolopyrrole (DPP) molecules, i.e., DPPPy-Ph-F , DPPPy-Ph-3F , and DPPPy-Py-F , with medium bandgap were synthesized to coordinate with Lewis acid of B(C 6 F 5 ) 3 (BCF). By coordinating with BCF, as demonstrated by 1 H, 19 F, and 11 B NMR spectra, the bandgaps of these DPP molecules were depressed largely. For DPPPy-Ph-F , with two pyridine units flanking symmetrically, 2 eq of BCF converted the two pyridine nitrogens stoichiometrically to Lewis acid adducts, along with absorption bands red-shifted and bandgap depressed (1.89 vs . 1.80 eV). For DPPPy-Ph-3F , with two pyridine units flanked and trifluorobenzene capped, adding 2 eq of BCF was unable to convert the two pyridine nitrogens to BCF adducts completely, due to the strong electron-drawing ability of trifluorobenzene substituent on pyridine, reducing its basicity. After adding excess BCF to coordinate with nitrogens, the bandgaps of DPPPy-Ph-3F also decreased from 1.92 eV to 1.84 eV. For DPPPy-Py-F , with four pyridine units flanked, 4 eq of BCF were required to bind the pyridine nitrogens. Accordingly, the red-shift of absorption bands and the depression of optical bandgaps (1.96 vs . 1.75 eV) for DPPPy-Py-F were most striking among the three molecules. [ABSTRACT FROM AUTHOR]

Ink Engineering in Blade-Coating Large-Area Perovskite Solar Cells (Adv. Keywords: blade coating; ink engineering; large area; perovskite solar cells EN blade coating ink engineering large area perovskite solar cells 1 1 1 07/29/22 20220727 NES 220727 B Perovskite Solar Cells b Upscaling perovskite solar cells is a key factor for their industrialization. In article number 2200975, Zhanhua Wei and co-workers discuss the ink engineering in blade-coating large-area perovskite solar cells. [Extracted from the article]

Nitrogen-dopedgraphene (NG) is a promising conductive matrix material for fabricatinghigh-performance Li/S batteries. Here we report a simple, low-cost,and scalable method to prepare an additive-free nanocomposite cathodein which sulfur nanoparticles are wrapped inside the NG sheets (S@NG).We show that the Li/S@NG can deliver high specific discharge capacitiesat high rates, that is, ∼1167 mAh g–1at0.2 C, ∼1058 mAh g–1at 0.5 C, ∼971mAh g–1at 1 C, ∼802 mAh g–1at 2 C, and ∼606 mAh g–1at 5 C. The cellsalso demonstrate an ultralong cycle life exceeding 2000 cycles andan extremely low capacity-decay rate (0.028% per cycle), which isamong the best performance demonstrated so far for Li/S cells. Furthermore,the S@NG cathode can be cycled with an excellent Coulombic efficiencyof above 97% after 2000 cycles. With a high active S content (60%)in the total electrode weight, the S@NG cathode could provide a specificenergy that is competitive to the state-of-the-art Li-ion cells evenafter 2000 cycles. The X-ray spectroscopic analysis and ab initiocalculation results indicate that the excellent performance can beattributed to the well-restored C–C lattice and the uniquelithium polysulfide binding capability of the N functional groupsin the NG sheets. The results indicate that the S@NG nanocompositebased Li/S cells have a great potential to replace the current Li-ionbatteries. [ABSTRACT FROM AUTHOR]

Photoelectrochemical(PEC) solar water splitting represents a cleanand sustainable approach for hydrogen (H2) production andsubstantial research are being performed to improve the conversionefficiency. Hematite (α-Fe2O3) is consideredas a promising candidate for PEC water splitting due to its chemicalstability, appropriate band structure, and abundance. However, PECperformance based on hematite is hindered by the short hole diffusionlength that put a constraint on the active layer thickness and itslight absorption capability. In this work, we have designed and fabricatednovel PEC device structure with ultrathin hematite film depositedon three-dimensional nanophotonic structure. In this fashion, thenanophotonic structures can largely improve the light absorption inthe ultrathin active materials. In addition, they also provide largesurface area to accommodate the slow surface water oxidation process.As the result, high current density of 3.05 mA cm–2at 1.23 V with respect to the reversible hydrogen electrode (RHE)has been achieved on such nanophotonic structure, which is about threetimes of that for a planar photoelectrode. More importantly, our systematicanalysis with experiments and modeling revealed that the design ofhigh performance PEC devices needs to consider not only total opticalabsorption, but also the absorption profile in the active material,in addition to electrode surface area and carrier collection. [ABSTRACT FROM AUTHOR]

[Display omitted] • VRBEs in the Bi2+ 2P 1/2 ground state in NaYGeO 4 and NaLuGeO 4 were experimentally determined by thermoluminescence study. • Electron liberation from Bi2+ has been evidenced. • Fully control of Bi3+ trapping depth via conduction band engineering. • Rational design of new Bi3+-based afterglow phosphor. It is challenging to rational design persistent luminescence and storage phosphors with high storage capacity of electrons and holes after X-ray charging. Such phosphors have potential applications in anti-counterfeiting and X-ray imaging. Here we have combined vacuum referred binding energy diagram (VRBE) construction, photoluminescence spectroscopy, and thermoluminescence to study the trapping processes of charge carriers in NaYGeO 4. In NaYGeO 4 :0.004Bi3+ and NaYGeO 4 :0.004Bi3+,0.005Ln3+ (Ln = Tb or Pr), Bi3+ appears to act as a shallow electron trap, while Bi3+ and Ln3+ act as deep hole trapping and recombination centres. We will show how to experimentally determine the VRBE in the Bi2+ 2P 1/2 ground state in NaYGeO 4 and NaLuGeO 4 by thermoluminescence study. The electron trap depth produced by Bi3+ codopant in NaLu 1-x Y x GeO 4 :0.003Bi3+,0.008 Tb3+ can be adjusted, by increasing x, resulting in conduction band engineering. By combining Bi3+ as an electron trap and Bi3+ and Tb3+ as the hole traps, excellent X-ray charged afterglow phosphors were developed. The integrated TL intensity of the optimized NaYGeO 4 :0.004Bi3+ and NaYGeO 4 :0.003Bi3+,0.008Tb3+ after exposure to X-rays is about 4.5 and 1.1 times higher than that of the state-of-the-art BaFBr(I):Eu2+ storage phosphor. Intense initial Tb3+ 4f → 4f afterglow appears in NaYGeO 4 :0.003Bi3+,0.008Tb3+ and more than 40 h afterglow is measurable in NaYGeO 4 :0.004Bi3+ and NaYGeO 4 :0.003Bi3+, 0.008 Tb3+ after X-ray charging. We will show proof-of-concept anti-counterfeiting and X-ray imaging applications by using the developed afterglow phosphors and CsPbI 3 quantum dots. This work not only provides experimental evidence on the VRBE in the Bi2+ 2P 1/2 ground state in NaYGeO 4 , but also shows how to design and develop good afterglow phosphors for anti-counterfeiting and X-ray imaging by deeply studying and controlling the trapping processes of charge carriers in bismuth and/or lanthanides doped inorganic compounds. [ABSTRACT FROM AUTHOR]

Fullerene derivatives are considered excellent materials for the extraction and transportation of electrons in the production of efficient tin-based perovskite solar cells (TPSCs). However, it is not clear how the molecular structure of fullerene derivatives affects the efficiency and stability of TPSCs. In this study, the effects of fullerene derivatives, (6,6)-phenyl-C61-butyric acid hexyl ester (PCBH) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM), with different functional groups, on photovoltaic performance were investigated. The flexible alkyl chain of PCBH effectively improved the film morphology and stability, the electron extraction and transport capabilities, and the interface contact of fullerene and perovskite. As a result, the PCBH-based TPSC yielded a higher efficiency, of 9.21%, than the PCBM-based devices (7.54%). More importantly, the PCBH-based films exhibited higher stability and effectively suppressed the oxidation of Sn2+ by inhibiting oxygen permeation. Therefore, the PCBH-based devices exhibited significantly enhanced stability. This result indicates that optimizing the functional group of fullerene derivatives is crucial for improving the efficiency and stability of TPSCs. [ABSTRACT FROM AUTHOR]

A stable cyan-emitting perovskite was fabricated through the incorporation of two branched cations into methylamine-based halide perovskite, obtaining a stable and high PLQY of ~87.8%. Such superior optical merits endow the perovskite with high and stable performance in cyan and white LEDs. [Display omitted] • DMAPbBr 3 with hollow PbBr 3 − and high solubility (at least 2.0 M) was pre-synthesized. • Branched DMA+ and TmMA+ were adopted to form 2D/3D perovskites for the first time. • Both the effective blueshift (from 541 nm to 486 nm) and enhanced PLQY (from ~9.9% to ~87.8%) were achieved. • Stable cyan LED with improved durability and white LED with increased CRI (from ~73.1 to ~81.7) were fabricated. As an indispensable part of the visible light region, cyan emission (470 nm–500 nm) is of great importance in lighting, displays, and light communication. Metal halide perovskite materials have made significant progress in the field of luminescent materials and devices. However, the corresponding cyan emission through halide mixing is non-stable due to halogen migration and phase separation. Herein, we developed a steric stabilization approach to tune and stabilize the cyan emission of methylammonium (MA)-based perovskites. Dimethylammonium (DMA+) lead bromide, with the small DMA+ branched cation, was used as intermediate to react with MABr, forming blue-to-green emissive (MA) x (DMA)PbBr 3 +x compounds simular to the low-dimensional perovskites. Furthermore, protonated (trimethylsilyl)methylamine (TmMA), the larger branched cation, was adopted as an interlayer space to further reduce the perovskite dimension, tuning the emission to the cyan region. The combination of the two branched cations enabled us to achieve a champion photoluminescence quantum yield (PLQY) of ~87.8% (peak wavelength ~486 nm). Moreover, the as-synthesized double cations modified perovskites in combination with LED InGaN chip can be used to fabricate stable cyan emission LEDs with improved durability (over 1000 min) and white LEDs with increased color rendering index (from ~73.1 to ~81.7). [ABSTRACT FROM AUTHOR]

Formamidinium lead halide (FAPbX3) has attracted greater attention and is more prominent recently in photovoltaic devices due to its broad absorption and higher thermal stability in comparison to more popular methylammonium lead halide MAPbX3. Herein, a simple and highly reproducible room temperature synthesis of device grade high quality formamidinium lead bromide CH(NH2)2PbBr3 (FAPbBr3) colloidal nanocrystals (NC) having high photoluminescence quantum efficiency (PLQE) of 55-65% is reported. In addition, we demonstrate high brightness perovskite light emitting device (Pe-LED) with these FAPbBr3 perovskite NC thin film using 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) commonly known as TPBi and 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) as electron transport layers (ETL). The Pe-LED device with B3PYMPM as ETL has bright electroluminescence of up to 2714 cd/m2, while the Pe-LED device with TPBi as ETL has higher peak luminous efficiency of 6.4 cd/A and peak luminous power efficiency of 5.7 lm/W. To our knowledge this is the first report on high brightness light emitting device based on CH(NH2)2PbBr3 widely known as FAPbBr3 nanocrystals in literature. [ABSTRACT FROM AUTHOR]