Fig. 1. (Color online) Overview of various in-situ characterization techniques with different resolutions, from centimeter to nanometer, to study the dynamic structure-property relationship under manipulation.

Fig. 2. (Color online) In-situ optical microscopy for characterizations of organic crystalline films. (a) Schematic diagram of CoMiC-based analytical system along the entire flow path connecting flow pattern, crystallization, and thin-film properties (upper panel of (a)). Side-view in-situ image analysis of meniscus shape variation during the coating (lower panel of (a)). (b) In-situ microscopy images showing the variation of solution/thin-film boundary and crystallization process of doped TIPS-pentacene using the FM-CoMiC and the SHM-CoMiC^[22]. (c) Schematic diagram of top-view and side-view in-situ microscopy to investigate the relationship between 3D meniscus geometry and crystallization during solution shearing. (d) The top-, side-, and 3D-view microscopies for the visualization of the contact line/crystallization process and cross-sectional meniscus shape^[34].

Fig. 3. (Color online) In-situ AFM characterizations. (a) Evolutionary selection growth approach and time-lapse sequence of representative AFM images showing the morphological evolution of the precursors on the SiO₂ surface. Scale bar: 2 μm^[38]. (b) Schematic illustration of the experimental setup for in-situ AFM imaging with perfusion flow of the guest solution. (c) 1.0 × 1.0  µm² topographic images of the PCP surface taken at the indicated times under the perfusion flow of a 200 mM bpy solution with a constant flow rate. The high-resolution parts are 30 × 30 nm² phase images of the liquid–solid interface taken at lattice scale^[21].

Fig. 4. (Color online) (a) Device cross-section schematic showing the working principle of (left) OFETs, (middle) EGOFETs, and (right) OECTs^[52]. (b) AFM images (10 × 10 µm²) of n-type films (upper) P-90 and (lower) BBL. The films were immersed in 0.1 M NaCl at different conditions^[16]. (c) Instrumentation schematic of in-situ ESM using dual-amplitude resonance tracking centered around the contact resonance frequency. Schematics of different electrochemical transistor operating modes in the AFM experiment (lower). (d) Topography and ESM amplitude images of a typical P3HT film in 20 mM KCl. (e) AM–FM stiffness map (frequency) with a line-flattened processing^[20]. (f) In-liquid SDM setup for the nanoscale electrical characterization of a functional EGOFET. (g) Constant height electric force images expressed in capacitance gradient (64 × 13 pixels) at 180 nm. (h) Conductivity maps of the central part of the channel. (i) Topographic and mechanical phase of a different region of the channel measured in intermittent contact mode. Constant height electrical image of the same region for the transistor in-operando^[37].

Fig. 5. (Color online) In-situ X-ray characterization techniques. (a) Conceptual representation of the in-situ solution-shearing system. (b) Scattering regions captured by the high-speed GIWAXS detector for a representative solution-sheared TIPS-pentacene thin film^[71]. (c) Schematic view of in-situ stretching GIXD experimental setup and in-situ measurements of the structure and strain of a π-conjugated semiconducting polymer under mechanical load^[72]. Schematic representation of (d) nano-GIXD setup, (e) bottom contact OFET stack, and (f) typical diffraction patterns at polymer channel and electrode position^[73].

Fig. 6. (Color online) In-situ ultraviolet photoelectron spectroscopy. (a) Experimental design to examine the behavior of PE and MWNT/PEDOT:PSS films before and after high-temperature annealing^[80]. (b) Schematic diagram of the photoelectron spectroscopy setup with UV He II as the photon source. Upon irradiation with energy hv, photoelectrons are injected from the organic semiconductor sample via the photoelectric effect. (c) Energy level diagram of an organic semiconductor showing electrons being photoejected from a HOMO level to a state above the vacuum level with a finite kinetic energy. (d) Schematic diagram showing the experimental design used for in-situ ultraviolet photoelectron spectroscopy measurements^[81].