Tin(II) thiocyanate Sn(SCN)$_2$ as an ultrathin anode interlayer in organic photovoltaics

TL;DR

This paper demonstrates that ultrathin layers of tin(II) thiocyanate can serve as effective, transparent, and easily deposited anode interlayers in organic photovoltaics, significantly improving efficiency and reducing recombination losses.

Contribution

The study introduces Sn(SCN)$_2$ as a novel, solution-processable ultrathin interlayer material for OPVs, offering advantages over traditional materials like CuSCN.

Findings

Achieved up to 8.1% PCE with 7 nm Sn(SCN)$_2$ layer.

Demonstrated room-temperature solution deposition without annealing.

Reduced recombination losses due to exciton-blocking energy levels.

Abstract

We report the application of a coordination polymer semiconductor, tin(II) thiocyanate [Sn(SCN)$_2$] as an ultrathin anode interlayer in organic photovoltaics (OPVs). Sub-10 nm layers of Sn(SCN)$_2$ with high smoothness and excellent transparency having an optical band gap of 3.9 eV were deposited from an alcohol-based solution at room temperature without post-deposition annealing. Inserting Sn(SCN)$_2$ as an anode interlayer in polymer:fullerene OPVs drastically reduces the recombination loss due to the exciton-blocking energy levels of Sn(SCN)$_2$. At the optimum thickness of 7 nm, an average power conversion efficiency (PCE) of 7.6% and a maximum of 8.1% were obtained. The simple processability using common solvents gives Sn(SCN)$_2$ a distinct advantage over the more well-known copper(I) thiocyanate (CuSCN). The electronic and optical properties of Sn(SCN)$_2$ make it interesting for applications in large-area electronic devices.