Organic non-volatile memory devices were fabricated by employing organic field-effect transistors (OFETs) with poly(vinyl alcohol) (PVA) and poly(3-hexylthiophene) as a gate insulating layer and a channel layer, respectively. The 10-nm-thick nickel layers were inserted for better charge injection between the channel layer and the top source/drain electrodes. The fabricated PVA-OFET memory devices could be operated at low voltages (≤5 V) and showed pronounced hysteresis characteristics in the transfer curves, even though very small hysteresis was measured from the output curves. The degree of hysteresis was considerably dependent on the ratio of channel width (W) to channel length (L). The PVA-OFET memory device with the smaller W/L ratio (25) exhibited better retention characteristics upon 700 cycles of writing-reading-erasing-reading operations, which was assigned to the stability of charged states in devices.

Tandem polymer solar cells with MoO3/Ni/ZnO:PEOz interconnection layers exhibited PCE = 14.22% at the Ni thickness of 6 nm.

It is demonstrated that a heme protein (cytochrome c [Cyt c]) nanosphere plays a strong anchoring role in binding hydroxyl groups of poly(vinyl alcohol) (PVA) leading to outstanding high‐temperature (100 °C) retention characteristics of transistor‐type organic memory devices (TOMDs). The PVA:Cyt c layers are spin‐coated on indium tin oxide gate electrodes from aqueous solutions with various Cyt c contents up to 50 wt%, followed by the formation of poly(3‐hexylthiophene) (P3HT) channel layers and nickel/aluminum top source/drain electrodes in TOMDs. Results show that adding 20 wt% Cyt c improves the drain current of devices in the presence of good hysteresis characteristics, which are maintained even after exposure to high‐temperature conditions (100 °C). The excellent conservation of hysteresis characteristics is attributed to the formation of Cyt c nanospheres that act as an anchoring point to retard the relaxation of PVA chains via specific interactions (hydrogen bonding etc.) between amino groups in the Cyt c nanosphere surfaces and hydroxyl groups in the PVA chains. The optimized PVA:Cyt c layers (20 wt% Cyt c, thermal treatment at 100 °C) deliver excellent retention characteristics to TOMDs, whereas no memory function is measured in the case of the pristine PVA layers at 100 °C.

Making multijunctions in organic solar cells with solution‐processed polymeric bulk heterojunction (BHJ) layers, i.e., tandem polymer solar cells (PSCs), has been one of the state‐of‐the‐art approaches for the last two decades. Tandem PSCs can overcome the single‐junction Shockley–Queisser limit by improving light absorption as they can exploit the polymeric BHJ layers with poor charge carrier mobility as subcells with limited thickness. Herein, 13% efficient triple‐junction tandem PSCs with a nanocrated hybrid interconnection layer (hICL) can be achieved by controlling the BHJ thickness (60 nm) of middle subcells is demonstrated. The open‐circuit voltage and fill factor (FF) of the optimized triple‐junction tandem PSCs reach 2.14 V and 74.3%, respectively. The present approach of middle subcell thickness control, using the reproducible hICL‐based multilayer stacking technology, delivers a promising way to further extend the number of junctions leading to high efficiency tandem PSCs with enhanced open‐circuit voltages and FFs.