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Molecular semiconductors (MSCs) are known as ideal candidates for constructing room‐temperature spin‐charge interactive devices due to their long spin lifetimes and abundant photoelectric properties. These devices can achieve novel and valuable functionalities such as room‐temperature supply units of fully spin‐polarized current. Unfortunately, their performances (sub‐0.1 nA) remain unsatisfactory due to limited charge and spin injection efficiency, which can hardly be improved despite great efforts thus far. Herein, from the theoretical side, an interfacial tunnel layer with precisely‐controlled barrier in spintronic devices may simultaneously enhance spin and charge injection. Accordingly, a solution‐processed small molecule with smooth morphology and amorphous structure is introduced to form a uniform and well‐controllable barrier in molecular spin‐photovoltaic devices. By modulating the thickness to effectively control the barrier, both spin and charge injection efficiency increase by > 150%. Thus, the spin‐charge interactive functionalities as supply units of fully spin‐polarized current have also been significantly improved than the current record at room temperature, the output fully spin‐polarized current (>2 nA) is 1200%‐larger, and the output power increases by > 50 times. Moreover, the interface‐modified spintronic devices exhibit excellent stability even after 70 days of exposure to air, which is essential for practical applications in the future. [ABSTRACT FROM AUTHOR]

Metal halide perovskite light‐emitting diodes (PeLEDs) are gaining increasing attention as a promising candidate for the new‐generation display technology. Although tremendous progress has been witnessed in this field, the device performance of blue PeLEDs still lags far behind that of the green and red counterparts. In this work, an effective interfacial engineering is employed to boost the radiative recombination of blue perovskite film by introducing a multifunctional tetraethyl orthosilicate (TEOS) network on the grain‐growth substrate. Benefitting from the strong interaction between the TEOS molecule and perovskite nuclei, the perovskite crystallization dynamics are effectively regulated, contributing to significantly improved emitting film with uniformly distributed halogen and concentrated low‐dimensional domain. Additionally, the TEOS network can distinctly passivate the crystal defects at the buried perovskite interface owing to its adequate electron‐donating sites. Consequently, the target blue PeLEDs featuring a stable emission peak at 488 nm exhibit a champion external quantum efficiency of 17.3%, which is among the highest values to date. The results demonstrate the critical role of the surface molecular characteristics of the grain‐growth substrate in regulating the mixed‐halide blue perovskite crystallization. [ABSTRACT FROM AUTHOR]

Highlights from the article: Photovoltaic Devices: In Situ Observation of Crystallization Dynamics and Grain Orientation in Sequential Deposition of Metal Halide Perovskites (Adv. Funct. In article number 1902319, featuring a synchrotron-based in situ X-ray diffraction technique, Gang Chen and co-workers investigate the sequential deposition process of FAPbI SB 3 sb from a smooth PbI SB 2 sb film to a trilayer PbI SB 2 sb -FAI composite film and finally to the oriented perovskite film. The effects of the additive ions of Br SP - sp , Cl SP - sp , and MA SP + sp on the crystallization dynamics and grain orientation of the resultant perovskite films are also surveyed.

Metal halide perovskites have revolutionized the development of highly efficient, solution‐processable solar cells. Further advancements rely on improving perovskite film qualities through a better understanding of the underlying growth mechanism. Here, a systematic in situ grazing‐incidence X‐ray diffraction investigation is performed, facilitated by other techniques, on the sequential deposition of formamidinium lead iodide (FAPbI3)‐based perovskite films. The active chemical reaction, composition distribution, phase transition, and crystal grain orientation are all visualized following the entire perovskite formation process. Furthermore, the influences of additive ions on the crystallization speed, grain orientation, and morphology of FAPbI3‐based films, along with their photovoltaic performances, are fully evaluated and optimized, which leads to highly reproducible and efficient perovskite solar cells. The findings provide key insights into the perovskite growth mechanism and suggest the fabrication of high‐quality perovskite films for widespread optoelectronic applications. [ABSTRACT FROM AUTHOR]

Doping is an effective strategy to tune the electrical properties of organic semiconductors. Traditional solution‐processed doping methods, including "host‐dopant mixing‐doping" and "post‐fabrication doping" methods, present challenges for their use in applications in optoelectronic devices. This work reports about a novel method to prepare electrically doped films, the authors call orthogonal liquid‐liquid‐contact (OLLC) doping. In OLLC doping, dopant and polymer semiconductors are dissolved in water and an organic solvent, respectively, and electrical doping occurs during film formation at the orthogonal liquid‐liquid (aqueous‐organic) interface. A large free volume of polymer and dopant in their solutions enables diffusion for effective doping. Thanks to the high surface tension of water, nanometer‐thick polymer films form spontaneously on the aqueous surface and simultaneously get doped. The doped thin polymer films on the aqueous surface can be easily transferred to devices to facilitate hole collection/injection in organic photovoltaics and light‐emitting diodes with solution‐processed top electrodes. [ABSTRACT FROM AUTHOR]

The methylammonium (MA)‐free perovskite solar cells (PSCs) have drawn broad attention due to their excellent thermostability. However, the efficiency of these devices is inferior to most state‐of‐the‐art PSCs. Herein, the photovoltaic performance of the MA‐free PSCs is enhanced by constructing interfacial capping layers with a pair of alkylammonium halides, n‐propylammonium (PA) iodide and propane‐1,3‐diammonium (PDA) iodide. The structure and composition of the interfacial layers are comprehensively investigated and their correlation with the device performance is presented in terms of defect passivation efficacy, energy level alignment, and hydrophobicity for moisture resistance. The PSC devices based on the PAI and PDAI2 treated MA‐free perovskite films demonstrate better power conversion efficiencies (PCEs) and stabilities than the reference devices without the interfacial layers. Although the PAI‐treated devices exhibit the highest PCE of 21.1%, the PDAI2‐treated PSCs demonstrate the exceptional thermal and humidity stabilities. [ABSTRACT FROM AUTHOR]

In article number 1802250 Qing Lin, Ling Zhang, and co‐workers report an artificial "closed‐loop" structure for intravenous glucose‐responsive insulin delivery. An acid‐sensitive matrix forms the "inner core" and RBCm‐derived coating the "outer shell". Under hyperglycemic condition, the glucose internalized by the anchored glucose transporters is enzymatically converted into gluconic acid and subsequently triggers acid degradation of the "inner core" to secrete insulin. [ABSTRACT FROM AUTHOR]

An artificial "closed‐loop" system that mimics the glucose‐responsive insulin secretion of pancreas β‐cells can potentially improve the treatment efficacy for diabetes. Herein, a lipid bilayer‐coated polymeric nanoparticle (NP) with "core–shell" structure is designed. As far as it is known, it is the first and only intravenous nanoplatform utilizing enzymatic‐oxidation scheme to achieve glucose‐responsive insulin delivery so far. Ethoxy acetal–derivatized dextran nanoparticles (Ace‐DEX NPs) are constructed as "inner core" loaded with insulin, and coloading glucose oxidase (GOx) and catalase (CAT) endow the "inner core" excellent glucose‐sensitive ability. Red blood cell membrane (RBCm)‐derived coating is adopted as "outer shell." It collectively provides a closed microenvironment for GOx‐based enzymatic‐oxidation scheme and camouflages it from elimination. Above all, the anchored glucose transporters (GLUTs) on the "outer shell" are able to sense blood glucose levels and facilitate the transport of outer blood glucose getting inside. Under a hyperglycemic condition, the internalized glucose is catalytically converted into gluconic acid with the aid of the GOx and subsequently triggers acid degradation of the "inner core" to secrete insulin. By governing the blood glucose levels on an automatic and continuous basis, the RBCm‐Ace‐DEX NPs can effectively respond to hyperglycemia and turn to resting conditions under normoglycemia. Ethoxy acetal derivatized dextran nanoparticles (Ace‐DEX NPs) are constructed as "inner core" and red blood cell membrane (RBCm)‐derived coating is adopted as "outer shell". This glucose‐responsive nanoplatform can steadily circulate in the blood at normalglycemia. While under hyperglycemic condition, the glucose internalized by the anchored GLUTs is catalytically converted into gluconic acid with the aid of GOx and CAT and subsequently triggers acid degradation of RBCm‐Ace‐DEX NPs to secrete insulin. [ABSTRACT FROM AUTHOR]