An improved submicron gap thermophotovoltaic structure and method comprising an emitter substrate with a first surface for receiving heat energy and a second surface for emitting infrared radiation across an evacuated submicron gap to a juxtaposed first surface of an infrared radiation-transparent window substrate having a high refractive index. The devices, trays and methods allow multiple use of non-sterile medical devices with sterile medical devices for performing medical procedures requiring sterile conditions. The card is cooled and a second image is captured and digitized. In the general formula, R1 to R4 are each any one of hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, and a heterocyclic group.