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Please find the data supporting the results presented in the figures in CSV and TXT formats:

The data supporting each figure is contained in the subfolder with the corresponding name, i.e.,

"Figure 1 - Lower bounds on secure key rates"
"Figure 3 - Coincidence-to-accidentals Ratios"
"Figure 4 - Density matrices"

FIGURE 1: Lower bounds on secure key rates for DIQKD
at 2.1 µm, 1.55 µm and 770 nm in free-space at daytime. Comparison of the lower bounds on the secure key rates R for DIQKD as functions of the number of photons per pulse µ and total channel efficiency η at different wavelengths simulated based on solar photon flux density data at sea level and infrared atmospheric transmission spectrum in
Ref [21] in the manuscript. This simulation is based on the theoretical results in Refs. [15, 22] of the manuscript, and solar background flux measured in Ref. [29] in the main manuscript.

FIGURE 3. Coincidence-to-accidentals Ratios (C_AR): Measured coincidence-to-accidental ratio (C_AR) as a function of the averaged single count rates between detectors 1 and 2, for the (a) type-0 and (b) type-2 sources. The insets show the plots on logarithmic scales. The ‘single’ counts include the detector dark count rates of 500 Hz in each arm.

FIGURE 4. Density matrix reconstruction: The complex valued elements of the reconstructed density matrices for (a) type0 SPDC source (b) type-2 SPDC source, respectively.