Achieving 15.75% efficiency in solar cells: Advanced surface engineering using Tetra-Tert-Butyl-Tercarbazol-Benzonitrile and organic layer integration in n-type silicon wafer and hybrid Planar-Si systems

This study investigates the progress in n-type solar cells utilizing implanted Tetra-Tert-Butyl-Tercarbazol-Benzonitrile (TTB-TB-BNZ) front surface fields and diffused Ag rear emitters. The n-type structure utilizes a systematic approach involving surface passivation, localized laser ablation, and screen printing, similar to commercial p-type solar cells. This design enables the conversion from p-type to n-type cell production. Ion implantation allows for accurate management of doping profiles, improving processing sequences and increasing efficiency. Analysis indicates that reduced post-implant annealing durations lead to a shallower doping profile, enhancing short-wavelength response. Its results in efficiencies reaching up to 15.75 % on large-area 200 cm2 n-type wafers. The study also examines hybrid planar-Si/organic heterojunction solar cells, emphasizing Tetra-Tert-Butyl-Tercarbazol-Benzonitrile (TTB-TB-BNZ) to improve photovoltaic efficiency. UV–visible and fluorescence spectroscopy indicate a maximum absorption wavelength of 360 nm and an emission wavelength of 420 nm. The concentration of TTB-TB-BNZ in (4,4′-di(9H-carbazol-9-yl)-1,1′-biphenyl) (CBP) films reaches its peak effectiveness at 40–50 %, leading to notable enhancements in light absorption and charge transport. The Si/PEDOT: PSS heterojunction solar cells incorporating TTB-TB-BNZ demonstrate a power conversion efficiency (PCE) of 15.75 %. This result underscores the potential for scalable fabrication methods to improve photovoltaic performance.