heterojunctions have been constructed and demonstrated for controlling optical, [1] electrical, [2] mechanical [3] and magnetic characteristics. [4] In particular, semiconductor heterojunctions as the core of light-emitting diodes (LEDs) have played vital roles in electric-driven lighting and display devices. The electric potential of a semiconductor heterojunction has a strong positive effect on charge carrier transport at the interface and can tune/ control the behaviors of light emitting. [5] The advances in lighting technology have greatly promoted the development of artificial intelligence, biotechnology and flexible optoelectronics. [6] At present, almost all LEDs are driven by external power supply through wire connecting electrodes. However, the high-efficiency heterojunction material driven by Newton force to achieve the stress light-emitting devices is still limited in the present research. Thus, the exploration of such a new type of light-emitting device without wires and electrodes not only supplies advanced heterojunction systems for light-emitting but also provides a prospective reference for the future multiapproach energy conversion with extended applications.As a special type of light source, mechanoluminescence (ML) materials are capable of generating photon emissions in response to mechanical stimuli. In comparison with LEDs based on electroluminescence (EL), ML provides sustainable light output by excitation of mechanical energy ubiquitously available in nature. During the past decade, ML materials have attracted widespread interests due to their promising applications in stress sensing, display, artificial skin, bioimaging, anti-counterfeiting, structure fatigue diagnosis, night surveillance and flexible optoelectronics. [7][8][9][10] However, the recent developments of highperformance ML materials are not as fast as other luminescence systems such as photoluminescence (PL)/EL, which is attributed to the lack of rational design of ML material systems guided by the in-depth theoretical exploration in the mechanism. ML materials known to date are typically homogenous structures, which offer limited space for optimizing the ML performance. Therefore, further improving the ML performance by exploiting heterostructures remains a challenge for present research. [11,12] In this work, we fabricate a class of ZnS/CaZnOS heterostructures, which flexibly tune the efficient and reproducible Actively collecting the mechanical energy by efficient conversion to other forms of energy such as light opens a new possibility of energy-saving, which is of pivotal significance for supplying potential solutions for the present energy crisis. Such energy conversion has shown promising applications in modern sensors, actuators, and energy harvesting. However, the implementation of such technologies is being hindered because most luminescent materials show weak and non-recoverable emissions under mechanical excitation. Herein, a new class of heterojunctioned ZnS/CaZnOS piezophotonic systems is presented, which disp...

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International audienceTremendous enhancement of optical emission efficiency was achieved in fluorosilicate glasses by growing lanthanide doped fluoride nanocrystals embedded in oxide glass matrix. The formation mechanism of the microstructure was elucidated by combining solid-state NMR, scanning TEM, EDX map, and large-scale molecular dynamics simulations. The results reveal that the growth of fluoride nanocrystals in fluorosilicate glass was originated from fluoride phase separation. Atomic level structures of phase separation of fluoride-rich regions in oxyfluoride glasses matrix were observed from both EDX maps and MD simulations, and it was found that, while silicon exclusively coordinated by oxygen and alkali earth ions and lanthanide mainly coordinated by fluorine, aluminum played the role of linking the two fluoride glass and oxide glass regions by bonding to both oxygen and fluoride ions. © 2016 American Chemical Society

We describe the use of a layer-by-layer hierarchical nanostructure to exploit the synergy of different lanthanide ions for converting single wavelength excitation into emissions spanning the whole spectral region. By lining up a set of lanthanide ions with matched energy levels in a core–shell nanostructure, we demonstrate well-defined cascades of energy transfer that gives access to optical emissions from a large collection of lanthanide ions (Tb3+, Eu3+, Dy3+, Sm3+, Nd3+, Yb3+, and Er3+) after excitation into a common sensitizer of Ce3+ featuring a broad absorption. Through optimization of the nanoparticle structure and surface coating, high quantum yields of up to 90% are achieved. Our results highlight that the controlled energy cascades at nanometer scale provide new opportunities for applications such as fighting against counterfeiting and sensing small molecules.

Multimode luminescence with tunable optical properties is reported in lanthanide(III) and manganese(II) co‐doped CaZnOS crystals. The materials display distinct emissions under excitations of X‐ray, ultraviolet, and near‐infrared photons as well as mechanical action, respectively. The excitation dependence of emission spectra stems from varying host‐to‐dopant and dopant‐to‐dopant energy transfer processes involved in different luminescence modes. By controlling intracrystal energy transfer through control of dopant concentration and combination, the emission spectra are precisely tuned across the visible to near‐infrared. These findings highlight a facile approach to constructing multimode luminescent materials with intrinsically encrypted emission characteristics for advanced anticounterfeiting applications.