Titan3

CCO and Mg:CCO nanoparticles were dispersed into 2-MOE to make 2 mg mL⁻¹ suspensions for materials characterization and fabrication of P3HT:PC₆₁BM OSCs, PFBT2Se2Th:PC₇₁BM OSCs, PTB7-Th:ITIC OSCs, and MAPbI₃ PSCs. Just prior to film preparation, the suspensions were placed into a bath sonicator (Branson 3510, Plano, TX, USA) for 90 min, then filtered through a 1 μm PTFE filter (Thermos scientific, Titan3, Houston, TX, USA), re-sonicated for 90 min, and again filtered through a 0.45 μm PTFE filter (Biomed Scientific, Seattle, WA, USA).

TEM images of gold NP aggregates on a holey carbon film (Agar Scientific AGS147) were taken in a FEI Titan3 scanning transmission electron microscope operated at 300 kV, in which a small probe (~0.1 nm in diameter) was rastered across the sample and the scattered electron beam collected by an annular detector (annular dark-field imaging). With a sufficiently high inner collection angle (>60 mrad) of the high-angle annular dark-field image, the scattered intensity is largely incoherent (there are no contrast reversals) and intensity may be readily interpreted: when the atomic columns of a crystal are aligned with the electron beam, the bright peaks correspond to the atomic columns. Low Z elements or thin regions appear darker and the vacuum is black (zero intensity). A Hitachi S-5500 in-lens field emission scanning electron microscope was used to acquire scanning electron microscopy images of gold NP aggregates deposited on a p-doped silicon wafer (Sigma-Aldrich 647764) and gold NP dimers on an ITO-coated coverslip (acceleration voltage 3 kV).

Scanning electron microscope images were taken by Zeiss Sigma. Optical images were taken with an optical microscope (Olympus DX51). Raman spectroscopy and photoluminescence with an excitation wavelength of 532 nm were carried out using a Renishaw inVia. The atomic force microscope images were collected on an NT-MDT Ntegra Spectra. The ReS₂/WS₂ was transferred onto the 300 nm SiO₂/Si for such measurements. X-ray photoelectron spectroscopy was performed on a Thermo Scientific, ESCALAB 250Xi. The measuring spot size was 500 μm and the binding energies were calibrated by referencing the C 1 s peak (284.8 eV). The TEM images were taken with an aberration corrected, high-resolution TEM (AC-HRTEM, FEI Titan3 (link)) operating at 80 kV. X-ray diffraction measurements were performed using a Rigaku MiniFlex600 with Cu–Ka radiation over the range of 2θ=10∼80°.

Aberration-corrected high-resolution scanning transmission electron microscopy (HR-STEM) images were collected using a double aberration-corrected FEI Titan3 (60–300) operating at 80 kV at Penn State. All high-resolution STEM images are captured with a high angle annular dark field (HADDF) detector. A beam current of 45 pA, beam convergence of 30 mrad, and camera length of 115 mm are used for image acquisition.