Abstract
The facile in-situ fabricated interfacial layers for highly efficient and stable polymer solar cells (PSCs) have garnered extensive attention. Herein, low-temperature in-situ prepared ZnO derived from zinc acetylacetonate (Zn(acac)2) is used as electron extraction cathode interfacial layer (CIL) in inverted PSCs. The chemical component, optical features, electron mobility and charge transfer properties of the low-temperature in-situ obtained ZnO CIL are detailedly studied by X-ray photoelectron spectroscopy (XPS), ultraviolet visible (Uv–vis) spectra, space charge limited current (SCLC) and time-resolved photoluminescence (TRPL) measurements, respectively. The obtained ZnO layer demonstrates outstanding optical and electrical properties. Via fine-tuning the parameters of film processing, a record high power conversion efficiency (PCE) up to 11.65% is obtained for PBDB-T:IT-M-based PSCs, indicating ZnO significantly facilitates carrier transportation and induces fast charge transfer to electrode. The low-temperature in-situ prepared ZnO CIL can be further applied into the large-area and flexible PSCs.
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•Facile low-temperature in-situ synthesis is proposed to fabricate ZnO film.•ZnO is successfully used as cathode buffer layer in polymer solar cells (PSCs).•ZnO facilitates carrier transport and induces fast charge transfer to cathode.•A record efficiency up to 11.65% has been obtained for PBDB-T:IT-M-based PSCs.