We present a new
concept for a wearable oxygen (O2)
sensor for transcutaneous O2 pressure (tcpO2) monitoring by combining the technologies of luminescent gas sensing
and wearable devices. O2 monitoring has been exhaustively
studied given its central role in diagnosing various diseases. The
ability to quantify the physiological distribution and real-time dynamics
of O2 from the subcellular to the macroscopic level is
required to fully understand mechanisms associated with both normal
physiological and pathological conditions. Despite its profound biological
and clinical importance, few effective methods exist for noninvasively
quantifying O2 in a physiological setting. The wearable
sensor developed here consists of three components: a luminescent
sensing film attached onto skin by a carbon tape, an organic light-emitting
diode (OLED) as a light source, and an organic photodiode (OPD) as
a light detector. All the components are solution-processable and
integrated on a plane in a bandage-like configuration. To verify the
performance, tcpO2 variations by pressure-induced occlusion
were measured in the lower arm and a thumb by the wearable sensor,
and the results were comparable to those measured by a commercial
instrument. In addition to its flexibility, other features of this
sensor render it a potential low-cost solution for the simultaneous
monitoring of tcpO2 in any part of a body.
The interfacial electronic structures of a bilayer of fullerene (C60) and zinc phthalocyanine (ZnPc) grown on vanadium pentoxide (V2O5) thin films deposited using radio frequency sputtering under various conditions were studied using X-ray and ultraviolet photoelectron spectroscopy. The energy difference between the highest occupied molecular orbital (HOMO) level of the ZnPc layer and the lowest unoccupied molecular orbital (LUMO) level of the C60 layer was determined and compared with that grown on an indium tin oxide (ITO) substrate. The energy difference of a heterojunction on all V2O5 was found to be 1.3~1.4 eV, while that on ITO was 1.1 eV. This difference could be due to the higher binding energy of the HOMO of ZnPc on V2O5 than that on ITO regardless of work functions of the substrates. We also determined the complete energy level diagrams of C60/ZnPc on V2O5 and ITO.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.