Inkjet-Printed Tin Oxide Hole-Blocking Layers for Organic Photodiodes

We investigated the fabrication of inkjet-printed SnO2 hole-blocking layers (HBLs) for organic photodiodes (OPDs). HBLs printed at different drop spacings were fabricated, and the effect of printing parameters on the layer quality was analyzed. These layers were incorporated into polymer:nonfullerene bulk-heterojunction OPDs, and their influence on the rectification, spectral responsivity, specific detectivity, and detection speed of the device was investigated. The OPDs fabricated with a drop spacing of 35 mu m corresponding to a thickness of 31 +/- 7 nm exhibited the best overall performance. These OPDs reached state-of-the-art performance with spectral responsivities of >0.5 A W-1, low dark current densities in the order of 5 nA cm(-2), bandwidths of >2 MHz, and peak specific detectivities of similar to 10(11) Jones at 740 nm.