Application of Low-Pressure Assisted Coating Method of PEDOT:PSS on Silicon Nanostructures to Form Thorough Organic/Inorganic Junction

摘要

This work explores low-pressure assisted (LPA) method to improve coverage of solution-processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOTPSS) coated on silicon nanostructures (SiNS) to form thorough junction of hybrid solar cells. Previously, spin-coating is the most common process. However, it suffers incomplete coating profiles. Here we develop a modified technique to overcome this problem. In the beginning, both Si nanowire (SiNW) and Si nanohole (SiNH) arrays, fabricated by metal-assisted chemical etching, are placed on a holder inside a chamber, which is evacuated with a pump. PEDOTPSS is also dropped on the same holder, which is first tilted to clearly separate SiNS and PEDOTPSS. Afterwards, pump out the air in wire gaps or nanoholes, and then tilt the holder to make PEDOTPSS flow toward SiNWs or SiNHs. Due to air vacancy in SiNS, PEDOTPSS can infiltrate into wire gaps or nanoholes fluently. Finally, PEDOTPSS covered SiNWs and SiNHs are combined with ITO coated glass to form Si/organic hybrid solar cells. The results show that NW device with LPA method, power conversion efficiency (PCE), FF, R_s and R_(sh) are 10.87%, 71.75%, 1.93 Ω cm~2, and 943 Ω cm~2. For NH devices with LPA method, PCE, FF, R_s and R_(sh) are 10.13%, 69.45%, 2,43 Ω cm~2, and 980 Ω cm~2.