1：Experimental Design and Method Selection:

The study employed a linker-free self-assembly approach using electrostatic interactions between negatively charged PSs and protonated NCNTs. This design aimed to achieve oriented immobilization for efficient electron transfer without insulating linkers. Methods included extraction of PSs from spinach, hybridization with CNTs, and characterization using spectroscopic and electrochemical techniques.

2：Sample Selection and Data Sources:

PSs were extracted from fresh spinach leaves. NCNTs were synthesized as described elsewhere. Control samples included PEI-CNT and SDS-CNT for linker-mediated comparisons. Data were obtained from laboratory experiments and instrument measurements.

3：List of Experimental Equipment and Materials:

Equipment included an automatic squeezer (HP-MWF12, Hurom), homogenizer (Wise Tis HG-15A, Witeg Labortechnik GmbH), centrifuges, sonicator, potentiostat (IVIUM Technologies), microscope (LEICA DMI30000 B, Leica Microsystems), zeta potential analyzer (ELSZ-1000, Otsuka Electronics), TEM (FEI Tecnai F20, Thermo Fisher Scientific), FT-IR spectrometers (Bruker IF66/S and Hyperion 3000), Raman spectrometer (ARAMIS, Horiba Jobin Yvon), UV-vis spectrophotometer (UV-1800, Shimadzu Corp.), and fluorescence spectrophotometer (F-7000, Hitachi). Materials included spinach, Triton X-100, PEI, SDS, Nafion, buffers, and chemicals for electrochemical analysis.

4：Experimental Procedures and Operational Workflow:

PSs were extracted by squeezing spinach, filtering, centrifuging, and treating with Triton X-100 to isolate from thylakoids, followed by dialysis. Hybrids were formed by mixing PSs with NCNT, PEI-CNT, or SDS-CNT suspensions under stirring, then centrifuging and rinsing. Electrodes were prepared by mixing hybrids with Nafion, loading onto glassy carbon electrodes, and performing photoelectrochemical measurements in a three-electrode system with Ag/AgCl reference and Pt counter electrodes under illumination.

5：Data Analysis Methods:

Data were analyzed using UV-vis, FT-IR, Raman, PL, EIS, and chronoamperometry. PL quenching and lifetime were measured to assess charge transfer. EIS data were fitted with equivalent circuit models to determine charge transfer resistance. Photocurrent densities were calculated from chronoamperometry results.