A structurally pure, near-infrared emissive Nd-(5,7-dichloro-8-hydroxyquinoline) 4 tetrakis complex has been synthesized. When incorporated as a dopant in the blue emissive, hole conducting polymer poly(N-vinylcarbazole), PVK, sensitized neodymium ion emission was observed following photo-excitation of the polymer host. OLED devices were fabricated by spin-casting layers of the doped polymer onto glass/indium tin oxide (ITO)/3,4-polyethylene-dioxythiophene-polystyrene sulfonate (PEDOT) substrates. An external quantum efficiency of 1 × 10 − 3 % and a near-infrared irradiance of 2.0 nW/mm 2 at 25 mA/mm 2 and 20 V was achieved using glass/ITO/PEDOT/ PVK:Nd-(5,7-dichloro-8hydroxyquinoline) 4 /Ca/Al devices.

Atomic force spectroscopy and microscopy (AFM) are invaluable tools to characterize nanostructures and biological systems. Most experiments, including state--of--the--art images of molecular bonds, are achieved by driving probes at their mechanical resonance. This resonance reaches the MHz for the fastest AFM micro--cantilevers, with typical motion amplitude of a few nanometres. Next--generation investigations of molecular scale dynamics, including faster force imaging and higher--resolution spectroscopy of dissipative interactions, require more bandwidth and vibration amplitudes below interatomic distance, for non--perturbative short--range tip--matter interactions. Probe frequency is a key parameter to improve bandwidth while reducing Brownian motion, allowing large signal-to--noise for exquisite resolution. Optomechanical resonators reach motion detection at 10 --18 m.Hz --1/2 , while coupling light to bulk vibration modes whose frequencies largely surpass those of cantilevers. Here we introduce an optically operated resonating optomechanical atomic force probe of frequency 2 decades above the fastest functional AFM cantilevers while Brownian motion is 4 orders below. Based on a Silicon--On--Insulator technology, the probe demonstrates high--speed sensing of contact and non--contact interactions with sub-picometre driven motion, breaking open current locks for faster and finer atomic force spectroscopy.

A new concept of atomic force microscope (AFM) oscillating probes using electrostatic excitation and piezoresistive detection is presented. The probe is characterized by electrical methods in vacuum and by mechanical methods in air. A frequency-mixing measurement technique is developed to reduce the parasitic signal floor. The probe resonance frequencies are in the 1 MHz range and the quality factor is measured about 53 000 in vacuum and 3000 in air. The ring probe is mounted onto a commercial AFM set-up and topographic images of patterned sample surfaces are obtained. The force resolution deduced from the measurements is about 10 pN Hz−0.5.

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