1：Experimental Design and Method Selection:

The study involved designing a photothermoelectric detector using EuBiSe3 single crystals with metal contacts. The photothermoelectric effect was leveraged for broadband detection without bandgap limitations. Methods included crystal synthesis, device fabrication, and characterization of photoresponse.

2：Sample Selection and Data Sources:

EuBiSe3 crystals were synthesized via a pyrometallurgical procedure, and needle-like crystals were selected for device fabrication. Data were collected from measurements using various laser sources across UV to terahertz wavelengths.

3：List of Experimental Equipment and Materials:

Equipment included field-emission scanning electron microscope (MERLIN Compact FE-SEM, Carl Zeiss), high-resolution transmission electron microscope (JEOL JEM-2010), powder X-ray diffractometer (Bruker D8 Advance), single crystal X-ray diffractometer (Supernova, Rigaku-Oxford Diffraction), Raman spectrometer (LabRAM HR Evolution, HORIBA Jobin Yvon), sourcemeter (Keithley 2602B), optical cryostat system (ST-100, Janis Research Co., Inc.), network signal analyzer (SR780, Stanford Research Systems), and IR camera (Dali Technology Co. LTD, DL700). Materials included EuBiSe3 crystals, gold electrodes, glass substrates, high-resistivity silicon substrates, and various lasers.

4：0). Materials included EuBiSe3 crystals, gold electrodes, glass substrates, high-resistivity silicon substrates, and various lasers. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Crystals were synthesized, characterized using SEM, TEM, XRD, and Raman spectroscopy. Devices were fabricated by depositing gold electrodes on crystal ends. Photoresponse was measured under illumination from lasers at different wavelengths, with incident power monitored. Scanning photovoltage, temporal response, and thermoelectric measurements were performed in various environments (air, vacuum, cryogenic).

5：Data Analysis Methods:

Data were analyzed using linear fitting for responsivity, exponential fitting for response times, and theoretical models for thermal decay length and noise-equivalent power. Statistical techniques included comparison with literature values.