Qixuan Zhong

Silver bismuth sulfide (AgBiS2) quantum dots (QDs) are promising candidates for eco-friendly solution-based solar cells. However, structural defects in QDs hinder high efficiency. Controllable synthesis of AgBiS2 QDs remains challenging, often yielding crystals with surface and lattice defects that promote nonradiative recombination. Improving AgBiS2 QD quality before film formation is crucial, as synthesis-related imperfections often persist in devices and inherently limit effective passivation later on. This study presents a photoinduced surface reconstruction method for AgBiS2 QDs that achieves nearly perfect ionic ordering with lower lattice strain, leading to denser films and better band alignment with charge layers than the initial AgBiS2 QDs. Corresponding solar cells achieve a power conversion efficiency of 9.71%, exceeding 8.16% for untreated solar cells. By enhancing AgBiS2 QD quality at the source rather than relying solely on downstream passivation, this approach offers a complementary pathway to high-performance QD solar cells.

Reliable perception in complex and dynamically degraded environments remains a central challenge for both biological nervous systems and next‐generation embodied intelligent systems. Biological organisms mitigate uncertainty via complementary bimodal perception, where various sensory modalities jointly sustain adaptive behaviors. Inspired by the star‐nosed mole, we report an artificial visuo‐tactile afferent nerve based on an AgBiS ₂ quantum dot (QD)/IGZO heterojunction optoelectronic synaptic transistor. The artificial nerve supports sensory acquisition, neural‐like signal encoding, synaptic modulation, and adaptive actuation within a unified neuromorphic framework. Benefiting from interfacial carrier separation and persistent photoinduced charge dynamics, this synaptic transistor exhibits reconfigurable synaptic plasticity with intrinsically coupled bimodal synaptic modulation. External visuo‐tactile stimuli are first transformed into unified neuromorphic responses and subsequently mapped to threshold‐governed robotic behaviors, including directional motion, turning, and grasping. Device‐informed results demonstrate that device‐enabled bimodal cooperation enhances recognition robustness under degraded perceptual conditions. This work establishes a compact, physically grounded framework integrating bimodal perception and adaptive intelligence, with potential implications for next‐generation bioinspired neuromorphic systems.

Heteroatom doping of the ZnO electron injection layer (EIL) is widely applied to the fabrication of high‐performance quantum‐dot and perovskite light‐emitting diodes (PeLEDs), while group‐VA atomic dopant is rarely studied. Here, VA bismuth (Bi) with strong metallicity is screened as a substitution dopant to regulate the colloid size, surface terminal, and defect density of the ZnO precursor. The as‐fabricated Bi‐doped ZnO (ZnBiO) EIL shows enhanced conductivity, passivated trap states, more n‐type nature, and appropriate band alignment with FAPbI₃ (FA: formamidinium), contributing to smooth injection paths with minimal transport losses. Promoted by inhibited hydroxyl terminations of ZnBiO, the FAPbI₃ crystals grown into flat nanocylinder domains with higher crystallinity and area‐thickness ratio, leading to a champion PeLED efficiency of 22.3%, a high near‐infrared radiance of 684 W sr⁻¹ m⁻², and nearly an order of magnitude extended operational stability, which shows great promise of ZnBiO as the optimal EIL for various LED application scenarios beyond classical ZnMgO.

As the initial synthesized colloidal quantum dots (CQDs) are generally capped with insulating ligands, ligand exchange strategies are essential in the fabrication of CQD films for solar cells, which can regulate the surface chemical states of CQDs to make them more suitable for thin‐film optoelectronic devices. However, uncontrollable surface adsorption of water molecules during the ligand exchange process introduces new defect sites, thereby impairing the resultant device performance, which attracts more efforts devoted to it but remains a puzzle. Here, we develop a solvent‐engineering‐assisted ligand exchange strategy to revamp the surface adsorption, improve the exchange efficiency, and modulate the surface chemistry for the environmentally friendly lead‐free silver bismuth disulfide (AgBiS₂) CQDs. The optimized AgBiS₂ CQD solar cells deliver an outstanding champion power conversion efficiency (PCE) of up to 8.95 % and improved long‐term stability. Our strategy is less environment‐dependent and can produce solar cells with negligible performance variance for several batches across several months. Our work demonstrates the critical role of solvents for ligand exchange in the surface chemistry of CQDs and the realization of high‐performance photovoltaic devices in a highly reproducible manner.

As the initial synthesized colloidal quantum dots (CQDs) are generally capped with insulating ligands, ligand exchange strategies are essential in the fabrication of CQD films for solar cells, which can regulate the surface chemical states of CQDs to make them more suitable for thin‐film optoelectronic devices. However, uncontrollable surface adsorption of water molecules during the ligand exchange process introduces new defect sites, thereby impairing the resultant device performance, which attracts more efforts devoted to it but remains a puzzle. Here, we develop a solvent‐engineering‐assisted ligand exchange strategy to revamp the surface adsorption, improve the exchange efficiency, and modulate the surface chemistry for the environmentally friendly lead‐free silver bismuth disulfide (AgBiS ₂ ) CQDs. The optimized AgBiS ₂ CQD solar cells deliver an outstanding champion power conversion efficiency (PCE) of up to 8.95 % and improved long‐term stability. Our strategy is less environment‐dependent and can produce solar cells with negligible performance variance for several batches across several months. Our work demonstrates the critical role of solvents for ligand exchange in the surface chemistry of CQDs and the realization of high‐performance photovoltaic devices in a highly reproducible manner.

X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX₃ nanocrystals (NCs). However, the proton exchange between coordinated OAm and OA may induce the detachment of ligands, resulting in poor performance after cleaning or long-time storage. Herein, density functional theory calculations predict that primary amines (L-type ligands) can stabilize a PbBr_x-rich surface and yield a trap-free material with fully delocalized valence band maximum and conduction band minimum states, which can significantly improve the photophysical properties and stability of CsPbBr₃ NCs. Along this prediction, a room-temperature reprecipitation method using L-type ligands (OAm, n-octylamine, or undecylamine) as the sole capping ligand has been developed to synthesize high-quality CsPbBr₃ NCs with near-unity photoluminescence quantum yield and dramatically improved stability against purification and water treatment. The enhancement can be attributed to the strong binding of unprotonated amines to lead atoms and the effective surface passivation provided by the resulted PbBr_x-rich surface, which are highly consistent with the theoretical predictions. This work not only offers an approach to synthesize high-quality perovskite NCs but also provides an in-depth understanding of the surface modification of CsPbX₃ NCs for practical applications.

The practical applications of CsPbX3 nanocrystals (NCs) have been limited by their poor stability. Although much effort has been devoted to making core-shell nanostructures to enhance the stability of CsPbX3 NCs, it is still very difficult to coat CsPbX3 NCs with another material on a single-particle level. In this work, we report a facile one-pot approach to synthesize CsPbBr3@SiO2 core-shell nanoparticles (NPs), in which each core-shell NP has only one CsPbBr3 NC. The formation process has been carefully monitored. It has been found that the formation rates, determined by reaction temperature, precursor species, pH value, etc, of both CsPbBr3 and SiO2 are critical for the successful preparation of core-shell NPs. Thanks to the protection of SiO2 shell, the product shows much higher long-term stability in humid air and enhanced stability against ultrasonication treatment in water than that of naked CsPbBr3 NCs. This work not only provides a robust method for the preparation of core-shell nanostructures, but also sheds some light on the stabilization and applications of CsPbX3 NCs.