UV−vis absorption measurements were performed with a Cary 5000 UV−vis−NIR spectrometer in solution. For photoluminescence (PL) measure-ments, a four-channel Thorlabs laser was used as the excitation light and a Kymera 328i spectrograph (Oxford Instruments, Andor) was used as the detector (<1600 nm). For PLQY measurement, a 935 nm laser, an integration sphere, and an Andor detector were used. The XRD data were collected using a Rigaku SmartLab powder diffractometer in the Bragg−Brentano geometry with Cu Kα radiation on drop-casted powder samples. The TEM images were obtained using a JEOL 2100F microscope operating at an accelerating voltage of 200 kV. TEM samples were prepared by dropping a diluted QD solution on ultrathin carbon grids. Scanning transmission electron microscopy (STEM) experiments were conducted using an FEI Titan G2 80-200 microscope at 200 kV equipped with a Cs-probe corrector and a HAADF detector. Elemental maps were taken by energy-dispersive X-ray spectroscopy (EDX) using four large-solid-angle symmetrical Si drift detectors. The XPS/UPS measurements were performed with a SPECS PHOIBOS 150 hemispherical analyzer under ultrahigh-vacuum conditions (10−10 mbar) with a monochromatic Kα X-ray source (1,486.74 eV). Current−voltage (I−V) measurements were performed with a Keysight Semiconductor Parameter Analyzer (B1500A) with the devices kept in a shield box. The EQE was measured using a Newport Cornerstone 260 monochromator, a Thorlabs MC2000 chopper, a Stanford Research SR570 transimpedance amplifier, and a Stanford Research SR830 lock-in amplifier. Calibrated Newport 818-UV and 818-IR photo- detectors were used as the reference. The nanosecond laser (520 nm) was used as incident light, which was modulated by a waveform generator (Agilent 33220A) at various frequencies with a 50% duty cycle to measure the 3dB bandwidth. For linear dynamic range measurements, a four-channel laser (Thorlabs) at 1310 nm was used as a light source at a frequency of 7 Hz modulated by an Agilent waveform generator. For the noise measurements, devices were connected with a Stanford Research SR830 lock-in amplifier directly.