1：Experimental Design and Method Selection:

The study involved designing a novel electron acceptor unit (BTI) and copolymerizing it with thiophene and bithiophene donors via Stille coupling to form polymers P1 and P

2：The polymers were characterized for thermal, optical, electrochemical properties, and used in device fabrication. Sample Selection and Data Sources:

Polymers P1 and P2 were synthesized and characterized; PC71BM was used as a blend material. Data were obtained from laboratory measurements.

3：List of Experimental Equipment and Materials:

Equipment included GPC for molecular weight, TGA for thermal stability, UV-vis spectrometer for absorption, CV for electrochemical properties, AFM for morphology, XRD for molecular packing, and Keithley 4200 SCS for electrical measurements. Materials included chloroform, chlorobenzene, and various chemicals for synthesis.

4：Experimental Procedures and Operational Workflow:

Polymers were synthesized, purified, and characterized. OFETs and phototransistors were fabricated in bottom-gate, bottom-contact configuration with Au electrodes, using spin-coating for film deposition. Electrical and photoresponse measurements were conducted under ambient conditions with NIR illumination.

5：Data Analysis Methods:

Mobility was calculated from transfer curves, photoresponsivity and photocurrent/dark-current ratio were defined and calculated from current measurements under illumination.