Fluorescence Enhancement of Metal-Capped Perovskite CH3NH3PbI3 Thin Films

We fabricate nano-structural metal films to improve photoluminescence of perovskite films. When the perovskite film is placed on an ammonia-treated alumina film, stronger photoluminescence is found due to local field en- hancement effects. In addition, the oxide spacer layer between the metal （e.g., AI, Ag and Au） substrate and the perovskite film plays an important role. The simulations and experiments imply that the enhancement is related to surface plasmons of nano-structural metals.

TiO2-Loaded WO3 Composite Films for Enhancement of Photocurrent Density

Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers＇ separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.

Phase Transformation and Enhancing Electron Field Emission Properties in Microcrystalline Diamond Films Induced by Cu Ion Implantation and Rapid Annealing

Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.

Recent advances in film cooling enhancement:A review

Film cooling is an indispensable scheme in the design of highly-efficient cooling configurations to satisfy the thermal protection requirement of turbine hot section components.During the last few decades,vast efforts have been paid on the discrete-hole film cooling enhancement.In this paper,some of the recent literatures related to the passive strategies(such as shaped film cooling holes,upstream ramps,shallow trenches,mesh-fed slots)and the active strategies(such as the use of pulsation modulating device or plasma actuator)for film cooling enhancement are surveyed,with the aim at presenting an updated overview about the state of the art in advanced film cooling.In addition,some challenging issues are also outlined to motivate further investigations in such a broad topic.

Angular color uniformity enhancement of white light-emitting diodes by remote micro-patterned phosphor film

Angular color uniformity(ACU)is a key factor used to evaluate the light quality of white-light emitting diodes(LEDs).In this study,a novel double remote micro-patterned phosphor film(double RMPP film)was used to enhance the ACU of a remote phosphor(RP)down-light lamp.A conventional RP film and remote phosphor film with single micro-patterned film(single RMPP film)also were examined for comparison.The angular correlated color temperature(CCT)distributions and the optical performance of the films were experimentally measured.The measurement results showed that double RMPP film configuration exhibited better color uniformity with a CCT deviation of only 441 K,compared with 556 K for the single RMPP film configuration and 1390 K for the RP film configuration.A simulation based on FDTD and ray tracing combined method also confirmed the ACU improvement.In addition,compared with the conventional RP film,the luminous efficiency of single and double RMPP film configurations was increased by 6.68% and 4.69%,respectively,at a driving current of 350 mA.The enhancement of the ACU and luminous efficiency are due to the scattering and mixing effect of the micropatterned film.Moreover,the double RMPP film configuration had better CCT stability at different currents than the other two configurations.The results demonstrated the effectiveness and superiority of double RMPP film in white LED applications.

Enhancement of second-order harmonic generation in polarized BaTiO_3 thin films embedded with Ag nanoparticles

RECENTLY, much attention has been paid to optical properties of ferroelectric thin films. Be-

Facile and robust strategy to antireflective photo-curing coating through self-wrinkling

We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ～ 8%, with an efficiency anti- reflection of 4% ～ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ～ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle