title: A 14.7% Organic/Silicon Nanoholes Hybrid Solar Cell via Interfacial Engineering by Solution-Processed Inorganic Conformal Layer.
abstract: We demonstrated a high-performance Si-organic hybrid heterojunction solar cell utilizing low-temperature and liquid-phase-processed TiO2as an interlayer between poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and Si nanoholes to produce a conformal contact on the surface of the Si nanostructure. The hydrophilic TiO2/Si-nanohole surface enabled the PEDOT:PSS to flow into the spacing of the close-packed nanoholes. Scanning electron microscopy images were used to confirm the PEDOT:PSS nanohole filling induced by the TiO2. With forming gas annealing of the double-sided TiO2, high Voc(0.63 V) and Jsc(35.7 mA/cm2) values were obtained, yielding a high power conversion efficiency of 14.7%. The high Vocwas attributed to the surface passivation of Si by annealed TiO2. The X-ray photoelectron spectroscopy investigation at the TiO2/Si interface indicates the TiOxsignal decreased and the TiO2and SiOxsignals increased after annealing. The Si-O bonding found in the O 1s study appeared in the form of Si-O-Si bonding to serve surface passivation. The band alignment of the PEDOT:PSS/TiO2/n-Si hetero-interfaces was postulated and plotted. The Vbiin the system after annealing was assumed to be higher because of the reduction of bulk and surface states that yield high Voc. After annealing, the Vbiincreased from 0.805 to 0.905 V. The reduction of surface recombination velocity proved the passivation ability of TiO2after annealing. With proven surface passivation and conformal PEDOT:PSS/Si nanohole interfaces for enhanced contact, this Si-organic hybrid heterojunction solar cell with solution-processed TiO2interlayers has excellent potential for application as a high-efficiency and low-cost Si solar cell.
authors.forename: Yu-Tsu
authors.initials: YT
authors.lastname: Lee
authors.forename: Fang-Ru
authors.initials: FR
authors.lastname: Lin
authors.affiliation: Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Chutung 310, Taiwan, ROC.
authors.forename: Chien-Hsun
authors.initials: CH
authors.lastname: Chen
authors.forename: Zingway
authors.identifier: http://orcid.org/0000-0003-0247-7446
authors.initials: Z
authors.lastname: Pei
keywords: conformal interfacial layer; hybrid organic/inorganic heterojunction; solar cell; solution-processed TiO2; surface inversion; trap assisted tunneling