The primary challenge in the research of micro-nano materials and devices is identifying target samples with research value from a vast pool of specimens. Common research tools include metallurgical microscopes, AFM, STM and so on. Among them, STM features high resolution and can provide abundant micro-morphology information. However, its drawback lies in sample preparation: gold sputtering or electron beam bombardment will cause damage to samples. AFM has the advantage of easy operation and enables multi-dimensional surface observation combining morphology, magnetism, electric potential and other properties. Nevertheless, its disadvantages are that probe consumables are fragile and the scanning speed is relatively slow. Overall, non-destructive observation via microscopes is most suitable for preliminary characterization and rapid screening of samples!
The E3-iFL bright/dark field fluorescence imaging microscope is equipped with a white LED light source for bright field observation and high-power 385/450 nm LED excitation light sources dedicated to fluorescence imaging. It supports bright field imaging, dark field imaging, polarized light imaging and fluorescence imaging simultaneously. It can effectively observe and distinguish various 2D materials, quantum dots, perovskites, nanowires, Micro-LEDs, minerals such as feldspar/mica/quartz, as well as other micro-nano materials and devices. The maximum observable area is 2.23 mm*1.24 mm (under a 5X objective lens). The filters are mounted on a rotating wheel for quick switching of imaging modes. The standard 450 nm LED fluorescence imaging function collects spectra within the range of 500–1000 nm, and a 385 nm LED can be pre-installed as an option.
Working principle of dark field observation: Dark field observation uses a central light stop or dark field condenser, with a parabolic condenser commonly used. It blocks the central light beam from the light source and only allows light to irradiate the sample at an oblique angle. The sample reflects or scatters the incident light, and the scattered light enters the objective lens. As a result, the background in the field of view appears black, while only the sample outline is visible. Benefiting from the high contrast brought by this special observation method, it can reveal more sample details than conventional bright field observation when the sample background condition is poor, and clearly distinguish edges of samples with different layers.
Working principle of fluorescence observation: Fluorescence observation uses light of a specific wavelength (usually ultraviolet or blue-violet light) to excite fluorescent substances in the specimen under the microscope so that they emit fluorescence. The E3-iEL adopts high-power blue LEDs (450 nm/385 nm). The blue light is reflected by a beam splitter and focused onto the sample surface through the objective lens. The fluorescence and reflected light emitted by the sample pass through a filter set; the reflected light is blocked by the filter set, while the fluorescent signal enters the camera for imaging. The camera is a cooled microscope camera for fluorescence imaging, fitted with an 8.3-megapixel high-sensitivity CMOS sensor. It supports long exposure with an exposure time ranging from 10 ms to 5 min, and features a TE cooling structure with a minimum operating temperature of -10 °C.
Examples of fluorescence applications:
Molybdenum diselenide (MoSe₂), enabling clear observation of the edge details of the sample
OLEDMobile phone screen (screen off)
CdTe cadmium telluride solar cells. (a) Standard scribing scheme; (b) SEM image of the scribed line; (c) Bright-field micrograph under a 5× objective lens; (d) Fluorescence micrograph under a 5× objective lens.
The fluorescence microscopy function enables clear observation and identification of whether the laser scribing of cadmium telluride cells is uniform and free of damage. Fluorescently excited CdS/CdTe can be observed at P1, P2 corresponds to the metal film layer, and P3 corresponds to the underlying EVA transparent adhesive.
Working Principle of Polarized Observation: Polarized microscopic observation can be used to distinguish samples with birefringence properties. That is, when light passes through a substance, the speed, refractive index, absorptivity, polarization, amplitude and other properties of light vary with the irradiation direction. Such substances are optically "anisotropic", also known as birefringent bodies, such as crystals and fibers. The E3-iFL comes with two polarizers. The polarizer installed between the light source and the objective lens is the "polarizer". Natural light becomes linearly polarized light after passing through the polarizer, and the vibration direction of linearly polarized light is consistent with the polarization direction of the polarizer. The other polarizer installed between the objective lens and the eyepiece is the "analyzer", which is used to check whether a beam of light is polarized light. After polarized light passes through the analyzer, the intensity of transmitted light changes as the analyzer is rotated.
Polarization Application Examples:
OLED screen (off state). (a) Polarizer at 350°; (b) Polarizer at 260°.
Images of mineral thin sections taken at proper polarizing angles, showing brilliant colors
Rapid Sample Screening:
With the brightfield, darkfield and fluorescence functions integrated into the E3-iFL, you can quickly complete preliminary screening of samples on a single device, saving time and efficiently selecting suitable samples. Application example:
Molybdenum disulfide MoS₂
Molybdenum diselenideMoSe2
Product parameters：
*Specific parameters shall be subject to the quotation document.
